The Intriguing Problem Of The Younger Dryas—What Does It Mean And What Caused It?

This is a follow up posting to Younger Dryas -The Rest of the Story!

Guest post by Don J. Easterbrook
Dept. of Geology, Western Washington University.

The Younger Dryas was a period of rapid cooling in the late Pleistocene 12,800 to 11,500 calendar years ago. It followed closely on the heels of a dramatically abrupt warming that brought the last Ice Age to a close (17,500 calendar years ago), lasted for about 1,300 years, then ended as abruptly as it started. The cause of these remarkably sudden climate changes has puzzled geologists and climatologists for decades and despite much effort to find the answer, can still only be considered enigmatic.

The Younger Dryas interruption of the global warming that resulted in the abrupt, wholesale melting of the huge late Pleistocene ice sheets was first discovered in European pollen studies about 75 years ago. Terrestrial plants and pollen indicate that arboreal forests were replaced by tundra vegetation during a cool climate. This cool period was named after the pale yellow flower Dryas octopetella, an arctic wildflower typical of cold, open, Arctic environments. The Younger Dryas return to a cold, glacial climate was first considered to be a regional event restricted to Europe, but later studies have shown that it was a world-wide event. The problem became even more complicated when oxygen isotope data from ice cores in Antarctica and Greenland showed not only the Younger Dryas cooling, but several other shorter cooling/warming events, now known as Dansgaard-Oerscher events.

The Younger Dryas is the longest and coldest of several very abrupt climatic changes that took place near the end of the late Pleistocene. Among these abrupt changes in climate were: (1) sudden global warming 14,500 years ago (Fig. 1) that sent the immense Pleistocene ice sheets into rapid retreat, (2) several episodes of climatic warming and cooling between ~14,400 and 12,800 years ago, (3) sudden cooling 12,800 years ago at the beginning of the Younger Dryas, and (4) ~11,500 years ago, abrupt climatic warming of up to 10º C in just a few decades. Perhaps the most precise record of late Pleistocene climate changes is found in the ice core stratigraphy of the Greenland Ice Sheet Project (GISP) and the Greenland Ice Core Project (GRIP). The GRIP ice core is especially important because the ages of the ice at various levels in the core has been determined by the counting down of annual layers in the ice, giving a very accurate chronolgoy, and climatic fluctuations have been determined by measurement of oxygen isotope ratios. Isotope data from the GISP2 Greenland ice core suggests that Greenland was more than~10°C colder during the Younger Dryas and that the sudden warming of 10° ±4°C that ended the Younger Dryas occurred in only about 40 to 50. years.

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Figure 1. Temperature fluctuations over the past 17,000 years showing the abrupt cooling during the Younger Dryas. The late Pleistocene cold glacial climate that built immense ice sheets terminated suddenly about 14,500 years ago (1), causing glaciers to melt dramatically. About 12,800 years ago, after about 2000 years of fluctuating climate (2-4), temperatures plunged suddenly (5) and remained cool for 1300 years (6). About 11,500 years ago, the climate again warmed suddenly and the Younger Dryas ended (7).

Radiocarbon and cosmogenic dating of glacial moraines in regions all over the world and abrupt changes in oxygen isotope ratios in ice cores indicate that the Younger Dryas cooling was globally synchronous. Evidence of Younger Dryas advance of continental ice sheets is reported from the Scandinavian ice sheet, the Laurentide ice sheet in eastern North America, the Cordilleran ice sheet in western North America, and the Siberian ice sheet in Russia. Alpine and ice cap glaciers also responded to the abrupt Younger Dryas cooling in both the Northern and Southern hemispheres, e.g., many places in the Rocky Mts. of the U.S. and Canada, the Cascade Mts. of Washington, the European Alps, the Southern Alps of New Zealand, and the Andes Mts. in Patagonia of South America.

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Figure 2. Temperature fluctuations over the past 15,000 years showing the abrupt cooling during the Younger Dryas and other warming and cooling periods, the Oldest Dryas (cool), Bölllng (warm), Older Dryas (cool), Allerød (warm), InterAllerød (cool), and Younger Dryas (cool).

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Figure 3. Oxygen isotope record from the Greenland ice core showing an abrupt temperature drop 12,800 years ago, 1300 years of cool climate, and sudden warming 11,500 years ago.

The Younger Dryas had multiple glacial advances and retreats

The Younger Dryas was not just a single climatic event. Late Pleistocene climatic warming and cooling not only occurred before and after the YD, but also within it. All three major Pleistocene ice sheets, the Scandinavian, Laurentide, and Cordilleran, experienced double moraine-building episodes, as did a large number of alpine glaciers. Multiple YD moraines of the Scandinavian Ice Sheet have long been documented and a vast literature exists. The Scandinavian Ice Sheet readvanced during the YD and built two extensive end moraines across southern Finland, the central Swedish moraines, and the Ra moraines of southwestern Norway(Fig. 4). 14C dates indicate they were separated by about 500 years.

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Figure 4. Double Younger Dryas moraines of the Scandinavian Ice Sheet.

Among the first multiple YD moraines to be recognized were the Loch Lomond moraines of the Scotish Highlands. Alpine glaciers and icefields in Britain readvanced or re-formed during the YD and built extensive moraines at the glacier margins. The largest YD icefield at this time was the Scotish Highland glacier complex, but smaller alpine glaciers occurred in the Hebrides and Cairngorms of Scotland, in the English Lake District, and in Ireland. The Loch Lomond moraines consist of multiple moraines. Radiocarbon dates constrain the age of the Loch Lomond moraines between 12.9 and 11.5 calendar years ago.

Multiple Younger Dryas moraines of alpine glaciers also occur throughout the world, e.g., the European Alps, the Rocky Mts., Alaska, the Cascade Range, the Andes, the New Zealand Alps, and elsewhere.

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Figure 5. Double Younger Dryas moraines at Titcomb Lakes in the Wind River Range of Wyoming.

Implications

The multiple nature of YD moraines in widely separated areas of the world and in both hemispheres indicates that the YD consisted of more than a single climatic event and these occurred virtually simultaneously worldwide. Both ice sheets and alpine glaciers were sensitive to the multiple YD phases. The GISP2 ice core shows two peaks within the YD that match the glacial record. The absence of a time lag between the N and S Hemispheres glacial fluctuations precludes an ocean cause and is not consistent with the North Atlantic Deep Ocean Water hypothesis for the cause of the Younger Dryas, nor with a cosmic impact or volcanic origin.

Both 14C and 10Be production rates in the upper atmosphere changed during the YD. 14C and 10Be are isotopes produced by collision of incoming radiation with atoms in the upper atmosphere. The change in their production rates means that the Younger Dryas was associated with changes in the amount of radiation entering the Earth’s atmosphere, leading to the intriguing possibility that the YD was caused by solar fluctuations.

Why the Younger Dryas is important

What can we learn from all this? The ice core isotope data were hugely significant because they showed that the Younger Dryas, as well as the other late Pleistocene warming and cooling events could not possibly have been caused by slow, Croll-Milankovitch orbital forcing, which occurs over many tens of thousands of years. The ice core isotope data thus essentially killed the Croll-Milankovitch theory as the cause of the Ice Ages.

In an attempt to save the Croll-Milankovitch theory, Broecker and Dention (1990) published a paper postulating that large amounts of fresh water discharged into the north Atlantic about 12,800 years ago when retreat of the Laurentide ice sheet allowed drainage of glacial Lake Agassiz to spill eastward into the Atlantic Ocean. They proposed that this large influx of fresh water might have stopped the formation of descending, higher-density water in the North Atlantic, thereby interrupting deep-water currents that distribute large amounts of heat globally and initiating a short-term return to glacial conditions. If indeed that was the case, then the Younger Dryas would have been initiated in the North Atlantic and propagated from there to the Southern Hemisphere and the rest of the world. Since that would take time, it means that the YD should be 400-1000 years younger in the Southern Hemisphere and Pacific areas than in the Northern Hemisphere. However, numerous radiocarbon and cosmogenic dates of the Younger Dryas all over the world indicate the cooling was globally synchronous. Thus, the North Atlantic deep current theory is not consistent with the chronology of the Younger Dryas.

The climatic fluctuations before and after the Younger Dryas, as well as the fluctuations within it, and the duration of these changes are not consistent with a single event cause of the YD. Neither cosmic impact or volcanic eruptions could produce the abrupt, multiple climatic changes that occurred during the late Pleistocene.

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204 Responses to The Intriguing Problem Of The Younger Dryas—What Does It Mean And What Caused It?

  1. higley7 says:

    OK, I’ll bite.

    If the Younger Dryas warming ended 11,500 years ago, how did it end the Ice Age 17,500 years ago?
    Just asking.

  2. Wasn’t there a big drop in dust starting about 20,000 years ago. As it dropped sunshine should have gone up.

  3. Stephen Richards says:

    I guess the lessons we still need to learn from these episodes of very rapid cooling and warming is that we still do not understand our climate. It is very possible that we are now entering an ice age or a period of rapid warming or that we are still plodding along the same line as that which began just after the end of the YD cooling. Worrisome really !

  4. Ged says:

    @Higley7,

    Look at the graphs, especially figure 1. What is confusing you?

    You have abrupt warming around 15,000 BC to levels comparible to today, and high above the ice age. Then Younger Dryas hits around 13,500 BC and temps plummet right back to ice age level. And then suddenly it rapidly warms right back up around 11,500 BC.

    So the ice age ended around 17,500, and no later than 15,000 with rapid warming, then there was the strange sudden cold snap we call Younger Dryas, and then back to warming when that ended at 11,500 BC.

  5. You will find under scrutiny that most of the glacial readvances happened just before or just after the Younger Dryas. Most notably the Two Creek glaciation event that turned out to be Allerod The only exception to that may be several Loch Lomond advances in Scotland.

    You will also find that several biota proxies do show a clear change in conditions but not necesarily in lower temperatures.

    For instance Bjorck et al 2002

    http://www.geol.lu.se/personal/seb/Geology.pdf.pdf

    or Lucke and Brauer 2004

    http://www.sciencedirect.com/science/article/pii/S0031018204002597

    who confirm the relatively warm and dry summers. The aridness is also confirmed in the Greenland ice core accumulation rates, which makes it extra difficult for glaciers to advance.

    So it appears that the Younger Dryas is riddled with interpretation issues.

  6. Lars P. says:

    You miss the big picture: when I looked at the first figure I recognised it looks like a diagram of an engine where somebody turned first time the key and it rumbled a couple of times before it died.
    That’s the Younger Dryas break.
    Then at the second key turn it started rumbling happily. It is just the diagnose sheet that you look at.

    Joking aside, thanks for the post, it is very interesting, I love these posts on climate history.

  7. Stephen Wilde says:

    I suggest that the 1500 year (approximately) Dansgaard-Oerscher events of which the YD was just a pronounced version would be a result of changing phasing between solar and oceanic cycles.

    The solar periodicity seems to be around 500 years as per MWP to LIA to date and the thermohaline circulation is around 1000 years.

    Over time they drift in and out of phase sometimes offsetting and sometimes supplementing one another.

    During the glacial epochs they seem to largely supplement one another to cause violent climate swings whereas during interglacials they seem to offset one another leading to a more stable climate regime.

    The Milankovitch cycles would still be the main driver of ice ages and interglacials but the sun / ocean interactions would affect the timing of the changes between ice ages and interglacials.

  8. rbateman says:

    Event windows during which bodies external to the Solar System entered, affecting all planets. One or more of the current planets may not have been here before the Events.
    It would take some time for the Solar System to stabilize into what we know today.
    We have evidence today of free-wandering planitessimals, so it’s possible.
    Do we have legend or myth that speaks of great disaster?
    All the earliest stories from antiquity say yes.
    We just don’t know the details.

  9. agfosterjr says:

    First, many thanks for your contribution and for stressing solar input as opposed to meteoric. But I am mystified as to how Milankovitch cycles can be discarded when we have such clear correlation as seen in this graph: http://en.wikipedia.org/wiki/File:Vostok_420ky_4curves_insolation.jpg

    Another question, do not ocean currents have instantaneous effects as well as long term? That is, turn off Arctic downwelling, which can only exit through the North Atlantic, and replacement surface waters flowing northward must be immediately terminated. We don’t have to wait a thousand years for oceanic turnover. Thanks, –AGF

  10. Andrew says:

    Don-It’s true that events like the younger dryas do not appear to be orbitally forced, but good agreement has been shown between the rate of change of global ice volume and the near Arctic circle summer insolation. It is certainly clear that some “spikes” of rapid change exceed what would be expected from Milakovitch alone, but I wouldn’t be so quick to say that the Milankovitch theory of the glaciations is “dead” at all. The long term correlation is quite good. We just need to invoke other factors for some episodes that deviate from the right Milankovitch model.

  11. Carsten Arnholm, Norway says:

    “…and the Ra moraines of southwestern Norway(Fig. 4).”

    Fig. 4 shows Finland, not Norway.

  12. About the sudden warming at the onset of the Bolling ~14500 years Cal BP, there are even more problems here, since the major glacial retreat started a few thousend years earlier. The problem was recognised by Denton et al 2006 and they dubbed it the mystery interval.
    (Denton G.H., Broecker, W.S. and Alley, R.B., 2006: The mystery interval 17.5 to 14.5 kyrs ago, PAGES news, 2: 14-16.)

    So if there are more not understood problems here, is it possible that one or more of our fundamental suppositions is fundamentally wrong?

    Also that quote: ” Evidence of Younger Dryas advance of continental ice sheets is reported from the Scandinavian ice sheet, the Laurentide ice sheet in eastern North America, the Cordilleran ice sheet in western North America, and the Siberian ice sheet in Russia.

    There was no Siberian ice sheet during the last glacial maximum, see for instance Hubberten et al 2004 http://epic.awi.de/9052/1/Hub2004a.pdf fig 1 on page 3. That was the maximum extent of the Eurasian ice sheet, way before the Younger Dryas. Let alone that there were glacial advances.

    Really the interpretation of the last glacial transition and many others are troubled by interpretation issues of certain proxies. However my explaining post in an earlier thread was moderated away.

  13. Dennis Cox says:

    The article states:

    The climatic fluctuations before and after the Younger Dryas, as well as the fluctuations within it, and the duration of these changes are not consistent with a single event cause of the YD. Neither cosmic impact or volcanic eruptions could produce the abrupt, multiple climatic changes that occurred during the late Pleistocene.

    In point of fact, since the given astronomical model for the Younger Dryas Impact Hypothesis is the progressive disintegration of the progenitor of the Taurids, as described in The Structure, and Evolution of the Taurid Complex by D.I. Steel et al. and proposed in W.M. Napier’s Paleolithic Extinctions and the Taurid Complex, it should be noted that the YDIH as written does not propose a single event at all.

    The progenitor of the Taurid family of objects is thought to have entered the inner solar system, and a very short period elliptical orbit that crossed the orbits of all the planets of the inner solar system sometime between 20,000 and 30,000 YA. The astronomical data on the Taurids is as good as anything you can dig up with a shovel, and trowel. And that evidence indicates the 50 to 100 km wide Taurid Progenitor object immediately began to breakup as soon as it entered the inner solar system.

    The the Earth’s passage though the debris from the progressive breakup of the Taurid Progenitor would have resulted in devastating impact showers, and storms of varying intensity twice a year for thousands of years, both before, and after, the start of the Younger Dryas.

    The evidence so far is implying that the event at the start of the YD that produced a global impact layer comparable only to the Cretaceous/Tertiary boundary layer that marks the extinctions of the dinosaurs 65 million YA was only the worst of many annual cluster airburst events of varying intensity over a period that lasted for many millennia.

  14. crosspatch says:

    This might be some interesting reading as well:

    http://elpub.wdcb.ru/journals/rjes/v09/2007ES000250/2.shtml

  15. Peridot says:

    Very interesting and informative. Need more articles like this one.
    (On an irrelevant note, the Dryas octapetala grows wild, naturally, in Co Clare, Ireland and other places at or near sea level – also in my garden though I planted it there. However it is not pale yellow…it is always white-petalled).

  16. JohnH says:

    To a layman the Vostock ice core temperature plot seems to show at least seven sudden temperature spikes within the last 120,000 year cycle between major interglacial temperature peaks; raising the possibility that a common cause might be found for at least some of them?

  17. Jim Clarke says:

    What I find most interesting is that, according to the Greenland ice core (figure 1) Greenland has been about 3-5 degrees C warmer than it is now for most of the Holocene! All those gloom and doom studies about the rapidly melting Greenland ice sheet are maybe just picking up on the very beginning of a return to Holocene average!

    It is amazing to think that civilization actually took root and grew during a time when the Greenland ice sheet was trying to destroy the planet by being 3-5 degrees warmer. Good thing they didn’t know then what we think we know now. Would they have even bothered with Stonehenge, the pyramids and the Colosseum?

  18. P Wilson says:

    has no institution ever considered that there might be an irregular rotational hotspot in the earth’s core that gives more heat to the southern hemisphere during glaciations, and that it may be the cause of deglaciations? This is the case with some of Saturn’s moons Enceladus, where the southern tip is excessively warm, as a result of its core, and has more heat coming out of the southern cap, whilst the north is frozen. Geo-thermal events must have a considerable, if hitherto unstudied impact, particulary submarine.

    Its one of climatology’s great weaknesses that the entire earth is not studied, and only the atmposphere

  19. crosspatch says:

    You miss the big picture: when I looked at the first figure I recognised it looks like a diagram of an engine where somebody turned first time the key and it rumbled a couple of times before it died.
    That’s the Younger Dryas break.

    If you look at the Pleistocene 10Be levels in Figure 2 of the link I provided in my previous comment (Russian Journal of Earth Sciences) you see a rapid decline of 10Be (denoting increased solar activity) as it warms and then a very sudden and deep increase in 10Be production during the YD which would normally indicate a sudden and deep reduction in solar magnetic field activity. There is also, of course, another possible cause. To assume that 10Be production is a good proxy for solar magnetic activity one assumes that GCRs are constant. Maybe they aren’t. Maybe we are buffeted from time to time by “gusts” of dense cosmic rays or maybe sometimes pass through a “stream” of them where there are just more of them. The point is that it could be a combination of both things working at the same time. Maybe we get more GCRs hitting the atmosphere because the solar system is passing through an area with more GCRs and not because the sun changed. The GCRs are subject to being channeled by magnetic phenomena in the Galaxy.

    So while we do know that solar magnetic activity can modulate GCRs reaching Earth, to assume that is the ONLY thing that chances those numbers might be a bit naive. Maybe we are bombarded from time to time with what amounts to shock waves or gusts of these particles. Maybe we find ourselves in streams of them. But one things does seem clear: for most of the Pleistocene the 10Be production was much higher than it has been during the Holocene. Why? I guess we will find out “shortly”.

  20. This graph must be wrong because it doesn’t show the hockey stick. Has anyone found out if Michael Mann agrees with this graph? After all he is the expert of record.

  21. phlogiston says:

    The YD can be looked at as a cool interval or two successive warm intervals, the first short, the second long (the Holocene). The 2 warm periods of different length paradigm makes more sense. Just before the YD were deep glacial conditions and the YD was just a drop back to current glacial “normality” after an abortive jump to interglacial conditions. The first spike was an abortive interglacial, the second a “successful” one.

    Indeed, if we remind ourselves that these very short abortive interglacial spikes occurred regularly throughout the glacial period, then the YD cool interval disappears as an anomaly, it is just an abortive interglacial spike that just happened to occur shortly before the “successful” interglacial rize which – unlike the abortive spikes – held on stably to the interglacial attractor rather than falling away from it.

    Further, if we consider glacial and interglacial being alternate attractors in a nonlinear/nonequilibrium climate system, then abortive interglacial spikes and the less frequent interglacial rises which “stick” are an expected and normal behaviour.

    Thus the YD is not in any way a “problem” except a problem of imagination and paradigm of the observer. The need for every upward or downward wiggle of earths climate history to have some discreet and unique external forcing comes from ignorance of quasi-chaotic systems and a deficient paradigm. It is even slightly absurd to imagine the climate system to be so passive.

    Earth’s climate can change BY ITSELF.

    OK it might be entrained in a simple or complex way by external periodic forcing, but it is not slavishly forced. Hunting for the magic celestial rhythm is futile.

  22. Werner Weber says:

    In the articles, the sea level during the younger dryas is not mentioned (maybe I missed it). Looking at http://en.wikipedia.org/wiki/File:Post-Glacial_Sea_Level.png
    during lower dryas, the sea level is approx. halfway between the level at last glacial maximum around 20 ky bp near -120 m and the present day level, or, more precisely, at around 7 ky bp (near -3 m) , see http://commons.wikimedia.org/wiki/File:Holocene_Sea_Level.png
    There has been a rapid increase by 30 m between 15 ky bp and 14 ky bp, then a leveling off, another increase by 10 m before the younger dryas started, a second leveling off during younger dryas, and then the final increase by 65 m between 11 and 7 ky bp. This final and biggest increase of sea level occurred during the maximum of the Milancovitch cycle around 10 ky bp. Near the end of the sea level increase, there occurred the 8.2 ky bp event, a similar cold snap of about 50 years. Between 8 ky bp and 7 ky bp, there was a sea level increase by approx. 10 m – corresponding to twice the present content of the Greenland ice sheet.
    I would argue (similar to Stephen Wilde), that there is no reason to abandon the Milankovitch cycle ideas. In addition to the melting caused by the Milancovitch maximum, there occurred perturbations, during dryas, and at 8.2 ky bp, which could have been caused by solar activity or better the lack of it.
    But the period between 15 ky bp and 7 ky bp was a period of rapid changes, with many feed-back effects. Positive feed-back due to removal of reflecting ice shields, and negative feed-back possibly due to increase of water transport (due to lea level raise) in the great circulations such as the Antarctic Circumpolar Current (ACC). As the ACC splits off the Humboldt and Benguela currents, any increase of ACC would thus also affect, i.e. cool tropical climate which then feeds back into northern hemisphere climate.

  23. timetochooseagain says:

    Jim Clarke says: “What I find most interesting is that, according to the Greenland ice core (figure 1) Greenland has been about 3-5 degrees C warmer than it is now for most of the Holocene!”

    Indeed. And all that Methane trapped in Siberian Permafrost didn’t get released when:

    “Boreal forest development in this region commenced by 10,000 yr B.P. Over most of Russia, forest advanced to or near the current arctic coastline between 9000 and 7000 yr B.P. and retreated to its present position by between 4000 and 3000 yr B.P….During the period of maximum forest extension, the mean July temperatures along the northern coastline of Russia may have been 2.5º to 7.0ºC warmer than modern.”

    MacDonald, G.M., et al., 2000. Holocene treeline history and climate change across northern Eurasia. Quaternary Research, 53, 302-311.

    Amazing how climate disaster didn’t ensue due to the Holocene Optimum. Despite all the claims that big warming in the Arctic is the scariest thing ever.

  24. LazyTeenager says:

    The behavior looks like instability while on the cusp of a change from one state to another.

    If its not instabilities that develop when changing from a frozen world to an unfrozen world then we need external things that by coincidence happen to match the end of the frozen state.

    I am not sure the sun can show that kind of variability. Changes in the earths magnetic field perhaps?

  25. Rob L says:

    How far north did the antartic ice sheet extend? During ice age it seems likely that gap between Antartic and South America was frozen, clamping off ocean circulation. When it melted it would have a pretty massive global effect that may have overwhelmed warming trend for a while.

  26. crosspatch says:

    Amazing how climate disaster didn’t ensue due to the Holocene Optimum.

    Or during the optimum of the last interglacial which was even warmer than it was in the Holocene. Virtually every plant species alive today was alive during that period and survived it with only few exceptions of species that might have appeared since that time.

  27. Justthinkin says:

    Don….I was with you until you stuck that “global warming” into the end of the graph. sorta throws some doubt on the other assumptions.Or it could just be me :)

  28. mikelorrey says:

    I doubt very much that the Lake Agazziz related cooling would take 400+ years to spread from north to south.

  29. Rosco says:

    A super efficient stone age man’s carbon capture scheme ??

  30. KenB says:

    Excellent article, well presented, but I agree with Dennis Cox, no one can exclude impact or near miss from outer space. There is enough physical evidence to warrant consideration and modification as our knowledge grows. That is all part of the joy of science. Keep an open mind.

  31. Robert of Ottawa says:

    rbateman, I am still undecided on the flood myths. Is it due to the black sea flooding with the Dardenelles opening, or just due to glaial retreat? Or is it both. Interestingly, agriculture is though to have started in Asia Minor; maybe it started on farms 600 foot below current Black Sea levels, and tthe locals escaped the “deluge”. Of further note, the Biblical version involves Mount Arrarat, also in Asia Minor. I never did understand that as a kid; the Jews never lived in Asia Minor; now it makes more sense.

  32. Gregory Ludvigsen says:

    “Both 14C and 10Be production rates in the upper atmosphere changed during the YD. 14C and 10Be are isotopes produced by collision of incoming radiation with atoms in the upper atmosphere. The change in their production rates means that the Younger Dryas was associated with changes in the amount of radiation entering the Earth’s atmosphere, leading to the intriguing possibility that the YD was caused by solar fluctuations.”
    At about this time there was a magnetic reveral (the Gothenberg). Changes in the magnetic field of the Earth could have changed the amount of radiation entering the Earth’s atmosphere.

  33. beng says:

    ****
    Stephen Wilde says:
    June 19, 2012 at 1:40 pm

    The solar periodicity seems to be around 500 years as per MWP to LIA to date and the thermohaline circulation is around 1000 years.
    ****

    OK, but what could be the mechanism for a 500 yr solar periodicity? And is there any evidence?

    The sun is an extremely well-mixed & uniform plasma ball (compared to differentiated planets & their oceans and/or atmospheres). Yes, there are the fairly well-understood magnetic cycles in the convection zone, but these cycle back to ~same conditions every cycle. I’m not sure the sun’s uniformity allows for longer “cycles”. Of course, there’s the gradual compression & heating of the core as it gets denser, but that’s not important for the timescales in question.

  34. Neville says:

    The abrupt warming after the YD at GISP2 was 10c in one decade according to this article from NOAA.

    http://www.ncdc.noaa.gov/paleo/abrupt/data4.html

    Clearly our present small warming of 0.7c over the last 100+ years is not unusual or unprecedented.
    Also our present slight warming comes at the end of a minor ice age and after one of the coldest periods of the Holocene.
    This recovery is normal and to be expected. It is not unusual or unprecedented at all.
    But there are scores of these warmings and coolings throughout the glacials and interglacials, so what were the NATURAL causes during those times.,

  35. John Game says:

    Great article. Peridot has already commented that Dryas octopetala has white flowers (and it has eight petals, hence the name). But there is another Dryas species, Dryas dummondii, which grows for example in the Canadian Rockies and has yellow flowers that nod. Do we know which species the Younger Dryas is named for? I have always assumed its for D. octopetala, but I don’t really know. D. octopetala is a wonderful arctic-alpine plant in the rose family, occurring at or near sea level as one goes north, eg as Peridot mentions in western Ireland, but needing more elevation as one goes south, eg its in the Wallowas Mountains in Oregon and in the Rockies in Montana and elsewhere. It likes limestone, at least in nature, and I wonder if that impacted its distribution during the “Younger Dryas”.

  36. Brian in Champaign-Urbana says:

    Doesn’t Figure 1 have a typo error? It lists the Medieval Warm Period and Little Ice age incorrectly, those should be at 800 and 200 years BP marks. The larger warm period and cool period on #9 and #10 are the late Roman warm period and subsequent Dark Ages cool period that occur prior to the MWP and LIA.

  37. mysteryseeker says:

    Very good article Dr. Easterbrook. A couple of comments that in part are echoing Dennis Cook’s comments: 1) Why would an absence of a time lag negate the idea of a cosmic impact event? 2) Perhaps you might wish to check out a couple of references provided below that suggest the Younger Dryas may have taken hold in a year or even less. To me the most plausible way that such a rapid onset could takje place is through a significant cosmic event (likely a comet encounter). That said I ma becoming more and more confinced of the importance of solar variations to our climate, but not on the rapid scale that was displayed in the Younger Dryas Thank-you again Don, signed Rod Chilton.

    78) J. P. Steffenson et al., “High-Resolution Greenland Ice Core Data Show Abrupt Climate Change Happens in a Few Years,” (2008): Science 321, 680-683.
    79) K. Ravillious” Ice Age Took Hold in Less than a Year,” (2009): New Scientist, 10.

  38. crosspatch says:

    During ice age it seems likely that gap between Antartic and South America was frozen, clamping off ocean circulation.

    Ice floats. It probably didn’t freeze all the way to the bottom. Could have certainly had an impact on currents, though, and there is evidence that it did. During the Pleistocene there was apparently a rather large area in the Southeastern Pacific that had no circulation for thousands of years during the glaciation. There was also a large increase in brine rejection from the increasing ice pack and this very dense, very cold water settled in that area and just sat. The restarting or speeding up or changing of ocean circulation could cause a lot of this really cold water to start moving around. What impact that might have will probably have to wait until 100K years or so for us to discover.

  39. mysteryseeker says:

    Sorry Dennis I of course mean Cox not Cook

  40. Ian W says:

    phlogiston says:
    June 19, 2012 at 3:06 pm

    I never thought I would agree with the Phlogiston theory ;-)

  41. feet2thefire says:

    The absence of a time lag between the N and S Hemispheres glacial fluctuations precludes an ocean cause and is not consistent with the North Atlantic Deep Ocean Water hypothesis for the cause of the Younger Dryas, nor with a cosmic impact or volcanic origin.

    Don, this is asserted but not explained. Just how is this time lag not consistent with either the NADOW or an impact scenario? How precise are the time increments of time that this is based on? Wouldn’t an impact cause non-lagged effects?

    Steve Garcia

  42. feet2thefire says:

    @crosspatch June 19, 2012 at 2:50 pm:

    If you look at the Pleistocene 10Be levels in Figure 2 of the link I provided in my previous comment (Russian Journal of Earth Sciences) you see a rapid decline of 10Be (denoting increased solar activity) as it warms and then a very sudden and deep increase in 10Be production during the YD which would normally indicate a sudden and deep reduction in solar magnetic field activity. There is also, of course, another possible cause. To assume that 10Be production is a good proxy for solar magnetic activity one assumes that GCRs are constant. Maybe they aren’t. Maybe we are buffeted from time to time by “gusts” of dense cosmic rays or maybe sometimes pass through a “stream” of them where there are just more of them.

    Just thinking out loud, but couldn’t the impact of a very large (~1.0 to ~2.0 km) cometary impactor as suggested possibly screw up the atmospheric shield, mimicking a change in the solar magnetic field? This posits a mechanism that is not now on the radar, I know. But it might also provide a mechanism for the sudden warming at the end of the YD – that due to the atmosphere returning to its previous condition, the shield could be reintroduced on a short time scale.

    IOW, might the impact, if big enough, with a plume/fireball large enough, suddenly change the chemistry of the atmosphere? And of so, what would it take to reverse that effect, and how short of time might it happen in? We do know the O18 changed. What else? Perhaps ozone? What else?

    I would point out that any hypothesis that tries to explain the YD onset or its end should also be required to explain the sudden increase of global temps at the end of the Allerod. (…at least as shown in the O18 and Be10 data) We have two big rises and one big decline. The impact hypothesis is addressing the decline, but everyone throws up their hands about the two increases. Those might be the elephant in the room.

    Steve Garcia

  43. Alex Heyworth says:

    J. Philip Peterson says:
    June 19, 2012 at 2:56 pm
    This graph must be wrong because it doesn’t show the hockey stick.

    Turn your screen upside down. Problem fixed.

  44. DAV says:

    Interesting shoe print in figure 5.

  45. crosspatch says:
    June 19, 2012 at 2:50 pm
    To assume that 10Be production is a good proxy for solar magnetic activity one assumes that GCRs are constant. Maybe they aren’t.
    The 10Be we measure is determined both by production [about 2 ounces per year total over the globe] and by deposition. The latter depends strongly on climate.

  46. commieBob says:

    I think the graph is labelled wrong. The MWP and LIA should be moved one hump to the right. I think the arrow for the MWP is pointing instead at the Roman Warm Period.

  47. Dennis Cox says:

    The absence of a time lag between the N and S Hemispheres glacial fluctuations precludes an ocean cause and is not consistent with the North Atlantic Deep Ocean Water hypothesis for the cause of the Younger Dryas, nor with a cosmic impact or volcanic origin.

    Hmmm,

    On the contrary, I’m thinkin’ that an event that produced a global impact layer is perfectly consistent with “The absence of a time lag between the N and S Hemispheres glacial fluctuations”. So while that absence of a time lag between the two hemispheres is not consistent with the Deep Ocean Water hypothesis, it is consistent with a cosmic event of sufficient magnitude that it simultaneously emplaced high energy blast-effected materials into a global stratigraphic layer.

  48. cotwome says:

    Just for fun:
    New Evidence Supports Cosmic Impact Theory

    http://www.archaeorama.com/archaeology/cosmic-impact-theory/

  49. dan johnston says:

    Couldn’t the YD events be the result of a cosmic impact, as accumylating evidence supports, followed by a Maunder-type solar minimum which slows the recovery? Eliminating an impact as a part of the puzzle may be shortsighted as sh*t happens.

  50. Milankovic cycles explain the longer term trends and snow and ice albedo changes explain the rapid transitions. They even explain the NH SH timing difference. Although the timing difference may be a dating problem with some of the Antarctic cores.

    New snow and ice has an a higher albedo than old snow/ice, because as snow/ice melts embedded dust accumulates on the surface decreasing the albedo.

    An increased in new snow/ice will trigger a positive (cooling) feedback. Similarly, an increase in snow/ice melt will trigger a positive (warming) feedback. Likely both are limited by solar insolation.

    These effects are much stronger in the NH because of the greater land area at the lattitudes they occur and would take a considerable period to warm/cool the SH perhaps needing ocean transport.

  51. LC Kirk, Perth says:

    Re the double lake caused by two moraine dams in Fig 5., I think I have seen rather a lot of these double lakes in glacial valleys: eg. Lake Neuchatel and Lake Biel at Neuchatel, the Thunenesee and Lake Brienz at Interlaken (both Switzerland), and possibly Loch Longy and Loch Ness (Scotland).

    Re the investigation of extra-terrestrial causes for such short-lived, dramatic climate variations: obviously we should be collecting comparable polar ice cores from ice caps on neighbouring planets or moons, eg. polar Mars. As I am sure we will be doing in due course. In fact one might even be able to raise sufficient funds now with a suitably worded proposal to a politically-sensitive agency..

  52. Steven Mosher says:

    “We just need to invoke other factors for some episodes that deviate from the right Milankovitch model.”

  53. QuantumPhysicistPhil says:

    Again problem is we overlook solar-magnetic/geomagnetic influence on the climate because we irrationally decouple those perturbations from the gravitationally-derived kinetic energy within the atmosphere..AKA circulatory mechanisms. Pumping mechanisms control the thermal-spatial profile from the tropics to the poles hence everything…ENSO lags change in the walker cell by 12-15 months, the walker cell lags changes in the polar annular modes by 1-2yrs. Many scientists ignore the QBO and polar annular modes as solar-magnetic driven (in the long run and short term via different mechanisms). What happened during the YD is clearly an excursion in the Earth’s geomagnetic field.

    Interglacial periods begin and end due to fluctuations in global pumping mechanisms that are operated externally via magnetic and kinetic forcings. Decrease the efficiency of global pumps and you:

    1) Tighten the lattitude based thermal gradient
    2) rapidly cool the polar regions
    3) Send the tropical thermal-spatial profile into overload hence erupt potent convection re flectingcoming light photons and increasing atmospheric charge seperation causing stagnation.

    This is how highly rapid climate changes occur naturally and it is induced externally on a cyclinic basis. I’ll leave the ‘cyclinic’ issue up for discussion as it is a very controversial topic. Eventually the truth will come out, though.

  54. John another says:

    Dennis Cox

    Thank you, thank you, thank you.
    Since childhood (50 ya), I have been unable to look at our own moon and think that Earth escaped the sources of all those impacts. Or what might be the shotgun effect of thousands of objects like ones that seem to just be missing us lately? Can you model the effect of a thousand 500 meter rock or nickle-iron objects striking in one pass? Los Alamos would seem well suited for such.

  55. Jeremy says:

    The Younger Dryas is one of the circumstantial evidence that supports the Cosmic Ray Flux (CRF) theory as a possible influence on climate. Just imagine the earth going through a bit of cosmic ray turbulence on our solar systems journey around the galaxy and voila you have a sudden cold period.

    Of course Milankovoch and many other things no doubt play a role too but CRF looks like a promising candidate (hypothesis) until someone comes up with something more plausible. I don’t buy ocean current theories and large releases of fresh water, as it all sounds so utterly contrived. CRF theory is neat and simple even if it remains only a mere hypothesis.

    There is a paper about this: Variations of Younger Dryas atmospheric radiocarbon explicable without ocean circulation changes Nature 403, 877-880 (24 February 2000) | doi:10.1038/35002547; Received 23 April 1999; Accepted 21 December 1999
    Tomasz Goslar, Maurice Arnold, Nadine Tisnerat-Laborde, Justyna Czernik & Kazimierz Wie cedilckowski

  56. QuantumPhysicistPhil says:

    BTW the Milankovic eccentricity pulses do not explain anything whether it be the termination rate or the timing…and must be discarded before it is too late to acknowledge the real mechanism, via the Milankovic eccentricity theory, the warming from the end of the LIA to the 1940s could not have taken place given insolation at the pole was already below 8 out of the last 11 interglacial terminations and albedo was certainly high enough to warrant a return to glaciation. Precession is the indirect governing factor here, and while precession is paced by eccentricity you have all the mechanisms relating to something we have been ignoring for too long..if it weren’t for the IPCC we’d probably be aware of what to do when we enter the next rapid global cooling period around 2017.

  57. feet2thefire says:

    The ice core isotope data were hugely significant because they showed that the Younger Dryas, as well as the other late Pleistocene warming and cooling events could not possibly have been caused by slow, Croll-Milankovitch orbital forcing, which occurs over many tens of thousands of years. The ice core isotope data thus essentially killed the Croll-Milankovitch theory as the cause of the Ice Ages.

    In a uniformitarian-only world, this conclusion is warranted. But as Stephen J Gould determined in paleontology, evolution isn’t one big slow, creeping gradualism. Instead, a punctuated equilibrium shows up in the record. Punctuated equilibrium MUST also apply to geology, no matter how much geologists resist.

    Paleontology cannot stand isolated and floating free in its stutterings; the stutterings must have causes. To pretend that the stutterings in the animal changes came about “just because” is to live in a magical garden. That animal changes – extinctions and new species – came about 65Mya is a given now, and it was due to the dinosaur killer at Xixcalub. But some argue that it never happened except that time. Iridium and nanodiamonds be damned, when the geologists don’t WANT it to be true. When they don’t like what it does to their paradigms and careers, they keep raising the bar and adding more and more hoops to jump through.

    “You found Iridium? That’s was good enough for Alvarez, but not good enough for Firestone or Kennett.”

    “You found nanodiamonds and Lonsdaelite, too? Piffle! Your super-experienced labs must have screwed up!” When this was later replicated by other labs, the response was, “But no never mind, because we have the ONE paper that we can keep referring to, so test all you want to, but our lab results will always trump yours! Mwah ha ha!”)

    The mammoths lived and thrived through the earlier ups and downs – some more severe than the YD onset – so cold alone did not kill them. The standard line of geologists answers nothing about the mammoths and dire wolves and sabre-toothed tigers. But come what may, SOMETHING caused those extinctions, and it happened just before that black mat was laid down. Yes, mammoths died earlier. Whoop de doo. Of course they did. But many died at the YDB and the standard line doesn’t explain it.

    Claiming that an impact could not cause instant changes – Don isn’t making sense on that one. An impact is one of the few processes that has the capacity to cause instant changes. Asserting it out of the blue, without explanation, is not science, it is science by declaration. The WUWT community has seen a lot of that in other areas of inquiry and won’t fall for that.

    Why geologists insist that Xixcalub was a catastrophe but there hadn’t been one since makes little sense. It is not as if they haven’t seen a comet cause monumental fireballs on a planet before – in the time of man. In the time of video, even. Was there an impact at the YD onset? Evidence keeps accruing that it did.

    Since it is controversial, the old guard will – of course – continue to pull up the uniformitarian spiel and argue that nothing could possibly have happened in the time of Man. That mind set was set in stone the minute Lyell latched onto Agassiz’ ice ages: Nothing happens that isn’t happening in their 19th century micro-moment in time. Framed within uniformitarian perception, all evidence will, OF COURSE, be seen by the old guard to support their gradualistic memes. What’s new? Science has ever been thus. New ideas are rebutted as long as possible by old frameworks – until the day comes when the old guard dies off – and new blood sees that the new framework answers more questions than did the old.

    Steve Garcia

  58. Jimmy Haigh. says:

    LazyTeenager says:
    June 19, 2012 at 3:23 pm

    It must have been CO2 surely?

  59. timetochooseagain says:

    Steven Mosher-Was there some point you were attempting to make by merely quoting me with no commentary?

    If you are attempting to suggest this is an absurd statement, it is clear that most of the variability of the rate of change of global ice volume of the last few hundreds of thousands of years is correlated with the summer insolation near the Arctic Circle. When the Milankovitch theory can explain the vast majority of the variability, and it can, it makes no sense to suggest we should not include it in explaining the variability because there are a relatively small number of instances were the data deviation from the Milankovitch model, if we use the right model for it’s effects.

    See figure 2 here:

    http://earthweb.ess.washington.edu/roe/GerardWeb/Publications_files/Roe_Milankovitch_GRL06.pdf

    The Milankovitch theory is too successful to justify throwing it out completely.

  60. QuantumPhysicistPhil says:

    Nanodiamonds are not necessarily a product of cosmic intrusion.

    The YD cooling cannot be explained by cosmic intrusion..you have zero hemispheric lag, a change in upper atmospheric chemistry ongoing for thousands of years, and a little gift in the NATL ridge outlining a method for geomagnetic reconstruction that reveals numerous large excursions during the time of the YD where the field went from potentially quadro-polar to bi-polar on numerous occasions WITHOUT a flip.

    These sort of excursions are evident throughout geologic history and appear to correlate well to precession. Hypothesis are abound.

  61. feet2thefire says:

    For those who keep bringing in Milankovitch cycles, those are part of the gradualistic POV. Those who invoke it for sudden changes have to explain how a gravitational or cosmic ray change down at the eleventeenth decimal point can cause a sudden change to occur within a ten-year span (and some papers argue that the YD happened within ONE year). Don is correct in arguing Milankovitch cannot be hauled out to explain the onset of the YD.

    On a take-off of the “extraordinary claims” truism: Sudden changes require sudden causes.

    No one in the YDIH community argues that gradual causes don’t exist or that they don’t continue through a catastrophic event. But while the event is occurring, the gradualism is like a gnat on an elephant’s back. When sudden 10° changes occur, to look for explanations in extremely gradual causes (and the Milankovitch is, if anything, über gradual) does not make logical sense.

    Analogy: When one sees a dead body by a road with a crashed car next to it, one does not start taking blood samples looking for a disease as the cause of death.

    It is not necessary – or useful – to drag in gradualist causes. All it can do is impede the inquiry. If YDIH opponents were arguing some other sudden cause, then we’d have a real discussion going. But instead, in order to try to EXPLAIN sudden effects, gradualist terrestrial processes are dragged in and contorted all out of shape – and everyone jumps up and says, “Yeah! It must have been an ice dam breaking! (anything gradualist!)”

    But Rodney Chilton catalogs the flaws in that ice dam guess (and it was just a guess), and it brings the gradualists out of the walls. Folks, the flaws do exist; the Laurentide Ice Sheet was not connected with the YD onset. At 12.9kya, the simple fact is that the LIS was still too far south to drain down the St Lawrence. But to make matters sillier, the gradualists then changed tunes and said the drainage was out to the NORTH – right into the teeth of the Ice Age frozen Arctic in the far west of Canada. One wonders just how the icebergs rafting stones around Greenland battled with the fresh water (that somehow didn’t freeze before getting to the N Atlantic). How convoluted can a Rube Goldberg (no pun intended) hypothesis get?

    Even those Dansgaard-Oescher and Heinrich Events are NOT necessarily icebergs rafting stones. That is only the INTERPRETATION given – another contorting of gradualism to explain sudden events. Ice bergs are gradualism, and dropping stones on the ocean bottom is merely a speculation to make gradualism sudden – just like the ice dams were. The evidence is the existence of stones on the ocean bottom, plus the climatic dips, in sudden dips. No one saw the icebergs. They are inferred.. No one has actually shown that those icebergs existed and did what they are claimed to have done. It is only an explanation that happens to fit in (by extraordinary contortions) with gradualism – and since it does fit in, it is generally accepted. A catastrophic event – in spite the evidence of their own eyes in July 1994 – of a comet hitting the Earth does not fit into gradualism – therefore it has to be denied at all costs, no matter how convoluted the alternative gradualistic explanation gets.

    At least in AGW the skeptics don’t invent extremely contorted processes to prop up our “denial.” We try to go with the solidest interpretations we can find.

    Steve Garcia

  62. Dennis Cox says:

    The Dryas event is one of scores of similar magnitude events over the Quaternary. Your argument implies an awful lot of cosmic events. Such events leave other signatures as well, iridium possibly, impact scars as well. Where are they all?

    Since the only other global layer in the stratigraphic record that contains the same assemblage of impact markers as the Younger Dryas Boundary layer is the Cretaceous/Tertiary boundary layer that marks the extinction of the dinosaurs 65 million years ago your claim of “scores of similar magnitude events all over the Quaternary” doesn’t hold up.

    To assume that all sudden and major climate changes during the Quaternary are the result of the same causative mechanism is begging the question.

    But the evolution of the Taurid complex, and the progressive disintegration of the Taurid progenitor during the Quaternary also describes massive quantities of dust in the Zodiacal Cloud, and inner solar system that would have had a dramatic and variable effect on the amount of solar energy available to the climate system during the Quaternary. To assume that such quantities of dust didn’t play a significant part as well would be to ignore a huge piece of the puzzle.

    As for impact scars, the supercomputer simulations done at Sandia Labs on the Tunguska event, and the event that produced the Libyan desert glass have shown that very large airburst events can melt, and efficiently ablate, significant amounts of terrestrial materials without producing any shock metamorphic effects at all. So before you go looking for “impact scars” you should note also that the current state of the science does not assume the direct kinetic impact of solid objects. From the Sandia simulations it is recognized that very large airburst events are capable of significant planetary scarring in the form efficient stripping, and ablation of melted materials. And without making anything that resembles what we thought an “impact scar” should look like.

    While there are a few good theories out there. They remain untested at this time. So the exact nature of the planetary scarring resulting from a very large cluster airburst event remains a mystery. We’re not even sure what to look for yet; much less where. But the answer to the tired old question of “Where’s the crater?” is simply that there doesn’t have to be one.

    The thing is, the specific argument of the Younger Dryas Impact Hypothesis isn’t that the YD cooling was triggered by an impact event. But simply that 12,900 years ago a cosmic event different from anything that’s ever been studied before emplaced high-energy, and high-temperature blast-effected materials into the stratigraphic record on a global scale that hasn’t been seen in 65 million years. The fact of the YD boundary as a global impact layer, has now been confirmed many times over. What remains is to unravel the consequences of the event.

    And ain’t it funny that the timing of that global catastrophic event just so happens to coincide with the start of the Younger Dryas Cooling? And that 35 genera in the northern hemisphere seem to disappear from the fossil record at just about the same dang time?

  63. GeoLurking says:

    snarkmania says:
    June 19, 2012 at 8:00 pm
    … Your argument implies an awful lot of cosmic events. Such events leave other signatures as well, iridium possibly, impact scars as well. Where are they all?

    GeoLurking says (the the previous Dryas Thread)
    June 16, 2012 at 10:49 pm

    Many times I have seen the impact idea for the Younger Dryas time period questioned due to the lack of an impact crater of the correct age.

    http://en.wikipedia.org/wiki/Willamette_Meteorite

    http://en.wikipedia.org/wiki/Cape_York_meteorite

    “Where are they all?”

    Dunno… show me the impact crater for those two meteorites.

    In the paper linked earlier by Dennis Cox (June 19, 2012 at 2:03 pm), “Paleolithic Extinctions and the Taurid Complex” you might take a look at the discussion on page one.

    …All three diamond allotropes are present in the boundary sediments including lonsdaleite (hexagonal nanodiamonds), which is shock-synthesised and found on Earth only in association with ET impacts or inside meteorites (Kennett et al. 2009).

    For Dennis Cox, thank you for those two papers!

  64. Jon says:

    “Nice article. In response to some other comments, I don’t see how anyone can claim to see a correlation between Milankovitch and past glacial oscillations. There are many intervals of time over the past several 100K glacial cycles where orbital forcing is the opposite of the global temperature trend. It’s no surprise that Principal Component Analyses applied to Milankovitch don’t match up with PCA applied to O18. I have seen a paper by Roe which shows a better match of these, but only when some nonlinear cause and effect assumptions are applied. When you invoke nonlinear causation, you can prove anything.
    Also amusing how people don’t seem to worry about squaring Milankovitch with pre Quaternary climate patterns, going back hundreds of millions of years, where no ice ages have been identified. Orbital cycling likely persisted throughout that period, but for some reason that no scientist has been able to explain, or has bothered to try to explain, Milankovitch impacts were apparently nil.

    I think the description of the sudden warming period (over decades) should by itself ‘kill’ any claims that current warming and sea level rise rates are unprecendented. And that should ‘kill’ any certainty about anthropogenic catastrophic climate change. But for some reason it won’t.”

    The last 27-30 million years the global climate has become gradual colder. In the last 5 million years it became both colder and more unstable. Ref. http://en.wikipedia.org/wiki/File:Five_Myr_Climate_Change.png

    To Me it seams that a warm Earth gives a stable robust climate and that a cold Earth gives a unstable climate that is easily affected by small input? And when you have a lot of possible factors you know you know, and factors you know you don’t know, and factors you don’t know you don’t know it’s a mess. Because anybody’s idea is as good as the rest.

    I think the only thing we can agree on is that the last 27 million years the global climate has gotten steadily colder. And as it gets colder it gets steadily unstable.
    ?

  65. ferd berple says:

    timetochooseagain says:
    June 19, 2012 at 3:19 pm
    Amazing how climate disaster didn’t ensue due to the Holocene Optimum. Despite all the claims that big warming in the Arctic is the scariest thing ever.
    ============
    The biggest climate disaster of all time took place during the Holocene Optimum. Humans switched from hunting and gathering to agriculture, and the rest is history. We need to switch back to a sustainable lifestyle as hunters and gatherers. Cut human population from 7 billion back to a more sustainable 7 million. Otherwise, we are all doomed to die within the next 100 years.

  66. HenryP says:

    I am glad to hear from Don Easterbrook again. I wonder what he says about my results which show that it is already getting colder on earth. For those of you who think that earth is still warming: you are wrong. From a sample of 45 weather stations taken randomly from all over the world, I find that earth has started cooling down from about 1994. Note that my sample of weather stations is well balanced by latitude and 70/30 sea – inland

    http://www.letterdash.com/henryp/global-cooling-is-here

    As I said before, the story of Noah is related in various forms in many peoples all over the world. Not only from the bible. It tells that at some stage 12000 BC the whole atmosphere fell down. This suggests people lived under much higher (water vapor) pressure before. Noah reports seeing a rainbow for the first time after the big flood. That means a different kind of moisturizing must have existed before, probably coming from the bottom (boiling at low temps.) , rather then from the top as rain.

  67. ferd berple says:

    Dennis Cox says:
    June 19, 2012 at 10:24 pm
    But the answer to the tired old question of “Where’s the crater?” is simply that there doesn’t have to be one.
    ===================
    The Tunguska event of 1908 is irrefutable evidence of this. It also shows these cosmic events are likely much more common than previously believed. Apart from the destruction, they leave no record to suggest a cosmic origin. As if the hand of god reached out and smote them.

  68. Jon says:

    “The biggest climate disaster of all time took place during the Holocene Optimum. Humans switched from hunting and gathering to agriculture, and the rest is history. We need to switch back to a sustainable lifestyle as hunters and gatherers. Cut human population from 7 billion back to a more sustainable 7 million. Otherwise, we are all doomed to die within the next 100 years.”

    I will be dead long before 2112. But how on Earth can you say or mean that and at the same time go on living?
    Because what you actually say is that you knowingly kill the Earth by allowing yourself to live?

  69. ferd berple says:

    “Then the Lord rained brimstone and fire on Sodom and Gomorrah, from the Lord out of the heavens” Genesis 19:24. “Turning the cities of Sodom and Gomorrah into ashes, condemned them to destruction, making them an example to those who afterward would live ungodly” II Peter 2:6.

    Substitute “Unknown” for “Lord”

  70. Dennis Cox says:

    ferd berple says:

    “Cut human population from 7 billion back to a more sustainable 7 million. Otherwise, we are all doomed to die within the next 100 years..”

    So what’s your preferred method of mass murder to accomplish the culling of a few billion people without ruining the environment for those who remain? And who decides who get’s taken out?

  71. Hoser says:

    crosspatch says:
    June 19, 2012 at 2:50 pm

    Hey! That’s a good idea.

    Hoser says:
    March 4, 2012 at 10:12 am

    Hoser says:
    August 25, 2011 at 12:53 pm

    Hoser says:
    January 12, 2011 at 9:50 am

    http://wattsupwiththat.com/2011/01/12/earths-changing-atmosphere/

    Hoser says:
    January 1, 2011 at 11:35 am

    http://wattsupwiththat.com/2011/01/01/time-magazine-and-global-warming/

  72. ferd berple says:

    Jon says:
    June 19, 2012 at 11:32 pm
    Because what you actually say is that you knowingly kill the Earth by allowing yourself to live?
    ========
    One can create any sort of nonsenses through words. For example:
    Nature will kill 99.99999% of everyone alive today by 2112. We call it old age. The law permits you to kill in self defense to prevent your own death. Thus, it is lawful to kill Nature to prevent your own death.

  73. HenryP says:

    Dennis Cox says:
    And who decides who get’s taken out?

    [SNIP: Sorry, Henry, but this is straying into areas removed from the thread and where we don't want to go - they seldom end well. Sorry. -REP]

  74. ferd berple says:

    Dennis Cox says:
    June 19, 2012 at 11:38 pm
    So what’s your preferred method of mass murder to accomplish the culling of a few billion people without ruining the environment for those who remain? And who decides who get’s taken out?
    =======
    What I said was if we didn’t take action “we are all doomed to die within the next 100 years.”

    How many times have you seen the same message as justification for extreme action?

    What happens if we do take action? we are all doomed to die within the next 100 years.

  75. Hoser says:

    Leif Svalgaard says:
    June 19, 2012 at 6:20 pm

    Exactly, that’s been my problem with the data too. However, if the variation is greater than could reasonably be explained by depostion rate changes, then we might infer another causative agent exists. The ratio of 10Be or 26Al to a non-cosmogenic substance similarly deposited in snow might be used to normalize the production of cosmogenic isotopes, possibly U in dust.

    Looks like someone is measuring isotopes of U and other non-cosmogenic isotopes in dust from ice cores.

    http://www4.ncsu.edu/~rojailal/science.pdf

    The variation in the Earth’s magnetic field may also influence cosmic ray effects.

    http://www.uvm.edu/cosmolab/people/larsenp/larsenms_proposal.pdf

  76. crosspatch says:

    Well, all production will eventually be deposited but I understand that the concentration one discovers at any particular point in time is going to depend on deposition rate at that time which poses a but of a chicken/egg problem. There can be some decoupling between deposition and production but I would not guess by very much (probably by no more than a decade at most) which is pretty small when we are looking on millennium timescales. And local deposition can vary from place to place but overall these 10Be fluctuations seems to indicate global changes. While it is likely we could have regional changes in deposition due to regional climate changes, these changes seem to be global. I mean, would we see a GLOBAL increase in rainfall to increase deposition? It would seem to me that at any given place when weather patterns change some places get wet and other places get dry.

    In other words, I would think that on longer global time scales, production would be what is driving the signal the most and deposition would be seen as local variation on the overall global regime.

  77. To further on the interpretation problems, if you would blank your Younger Dryas knowledge completely, erase all data and start reloading paleoclimatal data and information, looking at all the forests that got replaced with grass lands, spruce replaced by pine, thriving mammoth populations in high arctic Siberia, etc, etc, After all that, the conclusion would have to be that climate turned “continental” on a large scale, with hot and bone dry summers and cold winters.

    And now you bring this information to the ice cores where the sudden drop in isotope ratios suggest a ten degree temperature you know that something is clearly wrong. However a lot of the mysteries of the Younger dryas would never have been a mystery should the isotopes have been interpreted correctly, going back to the schoolbanks and scrutinze the water cycle with the fractination processes.

    So one might wonder if the researched did not cross check the isotopes to other proxies and data. Most certainly they did and when they did it, in the seventies and eighties of the previous century, and sure enough the year count in the ice cores seemed to match the carbon dating and there were many glacial advances that showed similar carbon dates with the counted years in the ice core. So it seemed a perfect match. However nobody was really aware of the calibration problems of carbon dating in that time, due to many variations that had yet to be discovered. We know all those problems now and as a consequence the carbon dates around the Younger Dryas are pushed back for some 2000 years, and so do all the glaciation dates. Hence all those glacial readvances did not occur in the Younger Dryas but in the Bolling Allerod.

    Also the mystery interval of Denton et al 2006 (17.5 ka – 14.5 ka), mentioned in my previous, is no longer a mystery interval if you realize that all the carbon dates associated with warming are also pushed back a few thousand years. For instance go back to my earlier quoted Hubberten et 2004

    http://epic.awi.de/9052/1/Hub2004a.pdf

    Goto fig 6 on page 7 (1339) and see that transition from Late Weichselian LW I to LW II from cool summers to dry and warm summers happened at 15 ka BP in carbon years. Now Lo and Behold, this seems to match the onset of the Bolling Allerod exactly. But the tragedy is that we have to calibrate that date first using INTCAL09 then we get to 18 Ka, which is even before the start of the mystery interval, confirming that the isotopes in the ice cores are lousy paleothermometers and the real story of the Mystery interval and the Younger Dryas is somewhat different.

  78. Monty says:

    The YD was not globally synchronous.

  79. Julian Braggins says:

    John another says:
    June 19, 2012 at 8:54 pm

    Dennis Cox

    Thank you, thank you, thank you.
    Since childhood (50 ya), I have been unable to look at our own moon and think that Earth escaped the sources of all those impacts. Or what might be the shotgun effect of thousands of objects like ones that seem to just be missing us lately? Can you model the effect of a thousand 500 meter rock or nickle-iron objects striking in one pass? Los Alamos would seem well suited for such.
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    I too have pondered on the craters of the Moon and Mars, to think that we have escaped them would be akin to claiming Divine Intervention.
    The difference surely is our atmosphere, most never reach the surface to leave impact sites, but the airbursts can still have catastrophic results for any living thing. That they only happened in ancient epochs is belied by the record of the ancient mythologies and archaeological records, man made and implied by fused sand and building stones, which isotope records and unexplained layers of carbonaceous material and frozen animal and plant “muck” thousands of feet deep only reinforce.

  80. Alex Heyworth says:

    ferd berple: you seem to have sucked in quite a few people who don’t understand irony.

  81. Bill Tuttle says:

    ferd berple says:
    June 19, 2012 at 11:32 pm
    The Tunguska event of 1908 is irrefutable evidence of this. It also shows these cosmic events are likely much more common than previously believed. Apart from the destruction, they leave no record to suggest a cosmic origin.

    Drop a 60-ton bolide on top of a mile of ice and you won’t find any crater after the ice melts. You’ll get a whale of a lot of water vapor, though…

  82. See this paper ref the effects of cosmic rays on climate
    [1] Scherer, K., H. Fichtner, T. Borrmann, J. Beer, L. Desorgher, E. Flukiger, H. J. Fahr, S. E. S. Ferreira, U. W. Langner, M. S. Potgieter, B. Heber, J. Masarik, N. J. Shaviv, and J. Veizer (2006) Interstellar-terrestrial relations: Variable cosmic environments, the dynamic heliosphere, and their imprints on terrestrial archives and climate. Space Science Reviews 127:327-+ doi:10.1007/s11214-006-9126-6.

  83. Alex Heyworth says:

    One thing that has not been looked at (as far as I know) is the possible influence of changes in the biosphere on climate over the last few million years. In particular, the change from forest domination to grassland. As well as the direct effect this might have had on climate, it has also led to a great increase in diatom populations because of increased nutrient runoff into the oceans.

    Research in this area seems to have focused on the influence of climate change on the biosphere, rather than the other way round.

  84. Interesting and good to see that over the past 10,000 years temperatures have been up to 2.5C warmer than today for 95%+ of the time. Makes Gore look a fool and the alarmist claim that a temperature rise of over 2C will instigate a tipping point.

    Thanks for the data.

  85. Tom in Florida says:

    ferd berple says:
    June 19, 2012 at 11:16 pm
    “Otherwise, we are all doomed to die within the next 100 years.”

    Yep, life is a bitch and nobody gets out alive. However, since more old people live in Florida and Florida has warm weather one could conclude that warm weather increases human life span.

  86. Harold Pierce Jr says:

    RE: Really Big Ice Comet

    Suppose a big comet of ice descended upon the north pole. In instant the Artic was blast frozen. The mammoths were quick frozen in their tracks.

    A comet of pure ice would leave no residues. Any evidence for such a comet?

  87. beng says:

    ***
    feet2thefire says:
    June 19, 2012 at 9:08 pm
    ***

    Thanks for the entertaining & informative post. I agree, the sudden global changes actually, IMO, support an impact scenario. The impact of Comet Levy-Shoemaker on Jupiter produced earth-sized fireballs/clouds. So a sufficient impact (or numerous, smaller, extended impacts) is going to surround the whole earth quickly in a debris/dust cloud, even away from the direct effects.

  88. Michael Schaefer says:

    This is a test.

  89. GeoLurking says:

    Harold Pierce Jr says:
    June 20, 2012 at 5:00 am

    Suppose a big comet of ice descended upon the north pole. In instant the Arctic was blast frozen. The mammoths were quick frozen in their tracks.

    A comet of pure ice would leave no residues. Any evidence for such a comet?

    According calculations (mine) based on the objects in the The MPC Orbit (MPCORB) Database, the average top speed of all objects is 25.15 km/s with a sigma (standard deviation) of 3.54 km/s. This means that most objects/minor planets will be traveling less than 32.23 km/s. (97%)

    The low end is in the 21 km/s range.

    What do you supposed will happen when an object, made of ice, hit’s the nice soft atmosphere of Earth at somewhere between 21 and 32 kilometers per second? At that speed, the atmosphere is harder than a brick wall. Much of your ice is going to ablate off, thermal and shock stress will start breaking it up. If it’s massive enough, some of it might be able to punch through all the way to the surface… but “blast freezing” is probably out of the question.

    http://www.minorplanetcenter.net/iau/MPCORB.html

  90. Dennis Cox says:

    Harold Pierce Jr says:

    RE: Really Big Ice Comet

    “Suppose a big comet of ice descended upon the north pole. In instant the Artic was blast frozen. The mammoths were quick frozen in their tracks”

    Nah, Even if it were made of pure water ice, a big chunk of something would still be subject to all the normal kinetic energy physics of a big impact. Hydrothermal explosive forces might play a role in the impact of such an object. But since you’d get temps hotter than the surface of the sun at the point of impact, instant freezing in the impact zone would most certainly not be a part of the picture.

    “A comet of pure ice would leave no residues. Any evidence for such a comet?”

    No. Although the chemistry of the remaining Taurids might give us a clue of what kind of stuff produced the impact markers in the Younger Dryas Boundary.

    Comet 2P/Encke is the largest known remaining fragment of the Taurids. And in 2003 NASA’s Astrobiology Institute did an investigation of the composition of comet 2P/Encke at infrared wavelengths.

    Project Investigators:

    M. Mumma, M. DiSanti, N. Dello Russo, B. Bonev, K. Magee-Sauer, and E. Gibb

    Project Progress:

    The composition of comet 2P/Encke was investigated at infrared wavelengths. Six nights of observing time was awarded at the NASA Infrared Telescope Facility and the W.M. Keck Observatory in November, 2003, for this Jupiter-family comet of probable Kuiper-belt origin. Long-slit spectra from the facility instruments CSHELL (Infrared Telescope Facility (IRTF)) and NIRSPEC (Keck) featured both high spectral dispersion and high spatial resolution about the nucleus. H2O, C2H6 , CH3 OH, HCN, and C2H2 were detected (the symmetric hydrocarbons for the first time in Encke), and production rates and rotational temperatures were determined. Rotational analysis of H2O and C2H6 suggested very cold rotational distributions for coma gases (T rot ~ 20 — 30K). Relative abundances for C2H6 , CH3OH, HCN, and C2H2 with respect to water were close to those typically seen in Oort cloud comets, while the abundance of hypervolatile CH 4 was severely depleted. This represents the most detailed study of a comet of probable Kuiper-belt origin with high-resolution ground-based infrared spectroscopy, and serves as a model for future studies of faint comets.

  91. Grey Lensman says:

    Climate is a long term feature , a response to many over lapping cycles and inputs. These include catastrophic events which can magnify or reduce cyclic events. Other events such as plate tectonics resulting in the closure of the Panama gap between North and South America, also effect climate

    Classic catastrophic examples being the KT event and the extinction of the dinosaurs. Along with the eruption of the super volcano mount Toba, which nearly caused the extinction of humanity.

    The YD event whilst looking similar to other events does have a multitude of other evidence pointing to a cosmic event being its cause. also notice the similarity with the YD and the Toba event, that both seemed to cause a 1.000 year cooling.

    Taking a bold step, if the YD resulted in the tearing out of the Grand Canyon, we have a similar volume of ejecta as the Toba event and a resultant similar 1,000 year cooling period. Evidence for ejecta dumps has been posted here

  92. a dood says:

    It makes you wonder how easy it will be to stop the advance of glaciers, next time an ice age hits.

  93. gymnosperm says:

    What is all the fuss?

    “This climate modeling experiment was performed using the GISS ModelE general circulation coupled atmosphere-ocean climate model by zeroing out all of the non-condensing greenhouse gases. Doing this removed the radiative forcing that sustains the temperature support for water vapor and cloud feedbacks, causing rapid condensation and precipitation of water vapor from the atmosphere, collapsing the terrestrial greenhouse effect, and plunging the Earth into an icebound state.

    The scope of the climate impact becomes apparent in just 10 years. During the first year alone, global mean surface temperature falls by 4.6 °C. After 50 years, the global temperature stands at -21 °C, a decrease by 34.8 °C. Atmospheric water vapor is at ~10%”

    Clearly, the non condensing greenhouse gasses were removed from the atmosphere at the beginning of YD, leaving all those massive feedbacks sitting on their hands; and put back at the end.

    Wink.

  94. the Gothenburg geomagnetic field excursion (13 000–12 000 years ago) http://www.sciencedirect.com/science/article/pii/003358947790031X
    may also be of interest

  95. Dennis Cox says:

    Bill Tuttle says:

    “Drop a 60-ton bolide on top of a mile of ice and you won’t find any crater after the ice melts. You’ll get a whale of a lot of water vapor, though…”

    Hmmm…

    Something like 1.1 billion tons of material is thought to have collided with this fair world of ours during the breakup of the Taurid Progenitor. Most of it was probably dust, and sand grain size. But there would have been some good sized chunks too.

    Check out this image of the cluster of fragments Comet Linear turned into when it broke up. [Link] And Linear’s a pretty typical example of a fragmented comet from the Taurid Complex.

    Since 20 tons is roughly equal to to one semi truck load, 60 tons isn’t really a very big bolide at all. How ‘bout a large cluster of a few thousand 60-ton bolides into a mile of ice? You’d get much more violence, but still no crater. What if the waters of lake Agassiz didn’t need an outlet at all because it all went up into the atmosphere as steam?

    I’ll bet it’d rain all over the northern hemisphere non-stop for weeks. Heck, you might even get enough water vapor in the atmosphere to make for forty days, and forty nights of torrential rains.

    It puts a whole new spin on the idea of a meltwater pulse.

  96. mysteryseeker says:

    Just to be brief: I think both Steve Garcia and Dennis Cox are both right on the mark at to the comet influence at 12,900 BP, and hence the cause of the YD. It is interesting too, that the cold interval of 8200 BP has many of the same signatures (though on a much smaller scale) as the Younger Dryas. Also, in response to Monty; As far as my delving into the synchronicity of the YD world-wide is concerned, I think a very good case can be made for this as real. Consider that the highest resolution ice core, Taylor Dome experienced the cold of the Younger Dryas. Admittedly, there is conflicting evidence in both New Zealand and also South America (higher latitudes) as whether the climate cooled or warmed. However, because the New Zealand and most South American studies are based upn glacial movements (known to be extremely difficult to determine the climate), then a much stronger canse can be made for world-wide synchronicity (if at all forcing When examining the interior of Antarctica ice cores cannot be accurately discerened because of their very poor resolution. So we are (with a bit of a stretch to be sure), but a valid scenarion nonetheless. And that is the idea of a sudden world-wide cold interval that may have set in a matter of years. Rod Chilton.

  97. Khwarizmi says:

    feet2thefire – In a uniformitarian-only world, this conclusion is warranted. But as Stephen J Gould determined in paleontology, evolution isn’t one big slow, creeping gradualism.
    = = = = = = = =
    I’m not sure if, in reality, a school of gradualism in geology exists, just as there is no school of pure gradualism in evolution, and there never was. In order to have an argument with the world, Gould had to misrepresent the primary literature, confident that his audience wouldn’t check it. In fact, “punctuated” evolution was first brought to you by … Charles Darwin:

    But I must here remark that I do not imagine that the process ever goes on so regularly as it is represented in the diagram, though in itself made somewhat irregular, nor that it goes on continuously; it is far more probable that each form remains for long periods unaltered, and then again undergoes modification.
    -Origin of Species, (6th ed., 1872) p.p.118-119

  98. agfosterjr says:

    leftturnandre says:
    June 20, 2012 at 12:55 am
    ===================================
    However improbably, everyone in the room just got a little dumber. Thanks.

    We’re not saying Milankovitch Cycles caused the Younger Dryas–those who know what M Cycles are fully understand the times scales are different. But again, correlation between June insolation at 65N latitude with O18 is undeniable–with the lag. Mystified at the deniers.

    One side of the moon is full of craters; the other side isn’t. The “isn’t” side is younger, and the contrast illustrates the evolution of the solar system from very dangerous to not so dangerous. The big planets have been sweeping up the planetoids for eons; all we have to worry about now is the Ort Cloud.

    50 year floods don’t happen every year. 100 million year catastrophes aren’t very likely in any given 20k year period (one chance in 5000). Extinction causing events are accordingly rare, unlikely in the lifespan of a given species. That is, a species is much more likely to to go extinct by emerging competetion, or it will evolve into a different but similar species, gradually of course.

    The presumed K/T catastrophe wiped out about 90% of identified species; we are reduced to speculation as to why those spared were spared. By being fossorial? By surviving as eggs which which when hatched needed no parental care? And the destruction didn’t discriminate by latitude or longitude.

    Modern humans on the other hand are wiping out species right and left, and the process didn’t start with the Industrial Revolution but with the mesolithic revolution. Seemingly simultaneously with the arrival of humans in the New World species began to disappear. Hardly a coincidence of 1/5000.

    The claim that a comet wiped them out leaves much to be explained. I haven’t heard yet whether the comet is supposed to have changed the climate and the climate did them in, or whether the comet killed off the big animals more immediately. In either case there are plenty of problems to address. Why did only the giant species disappear, leaving bear, bison, deer, etc., unaffected? Can a single species of small mammal, reptile, or amphibian be shown to have suffered, as 90% did with the K/T event? If climate is invoked, how do we explain the survival of mammoths in various islands, some far to the north? The scenario fits hunting extermination to a tee. Climate comes in a distant second. Meteoric extinction, even if they did leave uncommon remains of a sort we might expect every 10 or 20 thousand years, remains a 1/5000 likelihood. You have not yet begun to make your argument scientific. –AGF

  99. HenryP says:

    really, some interesting thoughts are expressed here,
    Henry@Dennis Cox
    yes, I was reasonably sure of that legend of the big flood 11-12k BC being correct because it is universally told all over the world, it could well have happened as you describe but I do not rule out other possibilities. Fact is that the mammoths were caught by the cold in their tracks, they simply had no way to escape the cold. Analyses showed that the meat froze within minutes from one end to the other end of the mammoth.
    Henry@Khwarizima
    It seems there were periods that the eggs of existing animals became exposed to radiation (from atomic bomb- like explosions) leading to different species.
    Like I said, when man plays with radiation you get bad mutations (Hiroshima) in the next generation of children, but when God (“the unknown from the outside”) plays with eggs you get, ehhh, ….. us……eventually …..
    Henry @ Don Easterbrook
    I would so much appreciate it of you could tell me what you think of my analysis that global cooling has already started…

    http://www.letterdash.com/henryp/global-cooling-is-here

  100. Dennis Cox says:

    Some of the denials of the YD impact event are getting ludicrous.

    There can no longer be any argument that the YDB layer is in fact a global impact layer. There is only one other global stratigraphic horizon with the same assemblage of impact markers; the Cretaceous/Tertiary Boundary layer.

    The amount of data from many different papers, and research teams, at numerous locations around the world have shown conclusively that the YDB has the most comprehensive set of high energy impact markers of any stratigraphic horizon in 65 million years. And the only thing anyone is “Invoking” an impact to explain is the ET chemistry, and high energy blast-effected materials in that 12,900 year old global stratigraphic horizon.

    Exploring possibilities, and speculating on what else the event may have caused should not be seen as ‘invoking’ it.

    To say that the authors and proponents of the YDIH are invoking an impact to explain anything else comes under the heading of invoking a straw man argument to side-step the point.

    But to pretend that an impact event of such magnitude had no effect on the climate, or biosphere of this world is absurd. And to leave the old Uniformitarian/Gradualist assumptive theories in the box in the light of this new knowledge doesn’t make a lot of sense either.

    One can explain the extermination of the giant animals by recognizing what effect the event must have had on the food supply.

    Much of the edible biomass of North America would have been burned away down to the last blade of grass. 

    The bigger you are, the more you need to eat every day. The animals that survived the impact event and didn’t face extinction were simply those that didn’t need to eat so much. 

    Most of the Mega fauna that went extinct after the event probably just starved. And with them went any specialist predators that depended on them for food.

  101. Duster says:

    higley7 says:
    June 19, 2012 at 1:05 pm

    OK, I’ll bite.

    If the Younger Dryas warming ended 11,500 years ago, how did it end the Ice Age 17,500 years ago?
    Just asking.

    It didn’t. The Wisconsinan Glacial ended about 17,000 BP. Conditions were generally warming for about 3,000 years. That warming trend was interrupted by the YD. Effectively, the YD delayed the onset of the modern climatic regime (the Holocene) by about 1,400 years. The YD was global in scale, was correlated with some very odd phenomena, occasionally suggested as causal agents for the YD, and ended just as abruptly as it started. There were lots of profoundly dramatic events taking place and there is no way to gauge their influence. Look up the Missoula or Spokane floods and wonder what effects they had on circulation in the Pacific.

  102. Duster says:

    As rule we like “simple explanations” where ever we can apply them and even where we can’t – viz the team’s insistence on CO2 as the cause of global warming, even though empirical evidence is against them. Like the YD is an event that was plainly more complex than any explanation offered for it can fully explain. It is possible for instance that what ever extraterrestrial event marked the initiation of the YD, may have simply imposed a signature effect on an already begun trend. We do not have data of adequate resolution to say. Similarly the freshening of the North Atlantic is proposed as a single event, but possibly a series of large melt events occurred rather than a single really large one. The Spokane Floods were like this. If these were coincident with the ET event, then the combined effect is not something any theorist has taken on.

    There is also a consistently unsung correlation that is persistently ignored by anyone who doesn’t use upper Pleistocene radiocarbon dates. The YD is also marked by a whopping C-14 anomaly. It is an anomaly so large that C-14 dates for the YD initially were thought to place the beginning around 12,500 BP – about 1,000 years too young. That anomaly makes all dates from the YD span far too young and also collapses around 1,500 years into an apparent 500 year span. That means that unless the ET event was a nuclear war, the sun’s and or the planet’s magnetic field(s) was significantly depressed for a fairly long time span, OR there was a supernova near enough to seriously irradiate the planet. So we have probably two unrelated ET events, one of which may have resulted in creased cloud cover, possible freshwater floods in two ocean basins on scales no modern human has ever experienced, possibly also a Daansgard-Oerschger event as well. Arguing about what “caused” the YD is very likely pointless, There was simply too much going on – “mammoth bad luck” one might say.

  103. Steve P says:

    agfosterjr says:
    June 20, 2012 at 10:03 am

    The scenario fits hunting extermination to a tee.

    You’ve dealt your own argument a serious blow by noting that bison and deer survived. Are we to understand that humans would rather hunt (and eat) big, tough Wooly Mammoths, when there are plenty of much tastier, substantially less formidable prey about?

    Native Americans had been killing and eating deer and bison for thousands of years before the arrival of the Europeans, apparently without making much of a dent in the vast herds of those animals.

  104. Steve P says:

    –sorry Mods; left off blockquote tags….
    agfosterjr says:
    June 20, 2012 at 10:03 am

    The scenario fits hunting extermination to a tee.

    You’ve dealt your own argument a serious blow by noting that bison and deer survived. Are we to understand that humans would rather hunt (and eat) big, tough Wooly Mammoths, when there are plenty of much tastier, substantially less formidable prey about?

    Native Americans had been killing and eating deer and bison for thousands of years before the arrival of the Europeans, apparently without making much of a dent in the vast herds of those animals.

  105. The reason for the YD cold period and the 8200 years ago cool period and all other cool periods and warming periods is due to VARIATIONS in solar activity. The sun drives the earth’s climatic /oceanic systems, therefore any change it may undergo will have an impact on those systems.

    I will follow with a more detail explanation of how this may all come about. All the other theories in my opinion are garbage when it comes to the initial cause of climate change ranging from Co2 increases, to changes in the Thermohalline Circulation,to geomagnetic jerks, to comet/asteroid impacts, ETC ETC. Ridiculous ,to say the least.

    It is the initial changes on the sun, followed by the secondary effects those initial changes on the sun have , that changes the climatic /oceanic systems of the earth, in all sorts of varying degrees ,due to the fact that the changes the sun undergoes varies in duration of time, and in degree of magnitude , on a constant basis.

  106. Since Oct .2005 solar activity went from a very active phase, to a phase of very little activity. Solar Cycle 24, is probably peaking, if it has not already done so in late 2011, and if this level of intensity turns out to be the peak for this cycle, it will make it as weak, if not weaker then very weak sunspot cycle 5, which brought on the DALTON MINIMUM. The DALTON MINIMUM , being a time of lower temperatures, more weather extremes and an increase in volcanic activity.

    Here we are in year 2012 ,and all the items which I feel control the climate are now set up to put us into a new climate regime,which will feature colder temperatures, and more extreme weather events. I expect the transition to take place between now and year 2014, and to be completed by no later then year 2017.

    I expect the above to take place because I expect the peak of solar cycle 24 to be ending in the very near future ,and that the next solar sunspot cycle, solar cycle 25,to be the weakest ever on record, way weaker then even solar cycle 24.

    WHAT IS IN PLACE TO CAUSE THIS CLIMATIC SHIFT?

    1. WEAK SOLAR ACTIVITY SINCE 2005 ,AND BECOMING EXTREMELY WEAK AFTER THE PEAK OF SOLAR CYCLE 24 PASSES BY. SOLAR FLUX READING WILL FAIL TO TOP 100 ,ONCE THIS PEAK PASSES,ALTHOUGH SOME SPURTS OF ACTIVITY WILL BE PRESENT FROM TIME TO TIME.

    2. VOLCANIC ACTIVITY WILL BE ON THE RISE,AS A RESULT OF THE MOSTLY WEAK SOLAR ACTIVITY,BUT WITH THE SPURTS OF ACTIVITY NEEDED TO MAKE AN INCREASE IN VOLCANIC ACTIVITY MORE LIKELY.

    3. THE PACIFIC OCEAN IS NOW AND WILL REMAIN IN IT’S COLD PHASE FOR AT LEAST ANOTHER 30 YEARS .ATLANTIC WILL BE IN THE SAME PHASE BY YEAR 2015.

    4. EARTH’S WEAKENED MAGNETIC FIELD WILL MAGNIFY CHANGES IN SOLAR ACTIVITY, CAUSING THOSE CHANGES TO HAVE A BIGGER IMPACT THEN IF THE MAGNETIC FIELD WAS STRONGER.

    5. LA NINA WILL BE THE RULE GOING FORWARD, RATHER THEN EL NINO.

    6. ARCTIC WILL EXHIBIT ABOVE NORMAL TEMPERATURES ,YES ABOVE NOT BELOW NORMAL TEMPERATURES.

    7. A WEAKER SOLAR WIND WILL ALLOW MORE COSMIC RAYS IN, WHICH WILL ENHANCE CLOUD COVERAGE. LOW CLOUDS.

    HOW DOES THE ABOVE MAKE IT COLDER?

    The weakened state of the sun will serve to cause a lesser amount of UV light to enter into our atmosphere ,which in turn will cause a change in the OZONE distribution and concentrations, in such a way that it will cause the atmosphere in the upper troposphere and lower stratosphere, to warm in the polar regions relative to the lower latitudes, which will in turn create a more MERIDIONAL atmospheric pattern (-AO).

    Also any spurts of activity will create more NO2 which also destroys OZONE.

    The other item, the increase in volcanic activity (especially if it is in the higher latitudes) will increase the amounts of SO2 particles in the atmosphere which will cause the stratosphere to warm , while the surface temperatures will fall. That is in general, which on balance should reinforce a more -AO atmospheric pattern. A key to having a climatic shift.

    The -AO ATMOSPHERIC CIRCULATION will enhance snow cover,cloud cover and precipitation for the N.H. This in turn will increase earth’s ALBEDO.

    The PDO in it’s cold phase alone, is enough to lower the temperatures on a global scale ,never mind the above ,I have just mentioned. The PDO being in it’s cold phase will likely aid to an increase in low cloud coverage,and will bring about an increase in cool LA NINAS ,as opposed to the warm EL NINOS. An increase in cosmic rays might enhance even more low cloud coverage.

    Most of the above happens in the NORTHERN HEMISPHERE, while the S.H. will show less dramatic effects due to the geography there, as opposed to the N.H.

    The S.H. is almost all water, which has a much higher specific heat ,then does land ,hence it is slow to heat up or cool down , in contrast to land. In addition a change in the atmospheric circulation in the S.H. would not change the snow cover as much in the S.H. since most of the snow would fall into water, and where it is already present, that being ANTARCTICA.

    Those climatic events in my opinion are much more pronounced in the N.H ,then the S.H, and when they happen, they happen very very fast. This is not a slow process, which is what the thinking was in the recent past.

    You need a set up to bring this about, I believe we have the set up ,it is in place. Once the set up is in place THRESHOLDS can be reached if duration and degree of magnitude of the items causing the set up are extreme enough. Again I think that will be the case, once the peak of solar cycle 24 comes to a close.

    Many people think and I say wrongly that it is a change in the ocean currents that bring about climatic change, such as a shift in the GULF STREAM, OR THE DEEP WATER THERMOHALINE CIRCULATION. My thinking is those don’t change, unless the atmospheric circulation changes. They follow ,they don’t lead. They of course will have a big impact on the climate ,if and when they change, but I think they are after the fact.

    Also ocean changes could not explain the many many temperature fluctuations the earth has and has had, with some changes being very abrupt. Example, the YOUNGA DRYAS, a deep cold period,that came on so fast and ended equally fast.

    In closing we know form looking at past history, that the earth’s climate is not really stable. Let me phrase that differently. It is fairly stable once it is in a particular regime , but the problem is from time to time it flips from one climatic regime to another climatic regime, that being glacial to interglacial. That is a fact,and I think the other fact is this is a quick process ,not a long drawn out process, due to the fact, set up’s get in place and they in turn eventually make it possible for thresholds to be crossed, which in turn ,results in the abrupt climatic changes that have taken place on earth in the past, and which will happen again in the future.

    If the earth’s climate were truly stable , we would never have has ice advances, and ice retreats.

    The other last point I want to make is, it is not easy to change the temperature of the earth, and yet at the same time it only takes a small change to make a big impact.

    There you have it, my thinking on what could happen this decade. Time will tell if this is right or not ,providing solar behavior does as is forecasted.

  107. Mainstream has their heads in the sand, and the SETUP is in place and has been in place for at least 3 years to cause this climate regime we are currently in, to finally change into another climate regime. Now when I say change into another climate regime ,that does not necessarily mean a drastic drop in temperatures, but what it means is the temperatures will decline ,and it won’t be gradual, it will be in quick jerks and these jerks could be as small as .2C to as much as 2.0 C, but the jerks themselves will be fast,although the magnitude of jerks in temp. will depend on how the items that control the climate phase in with one another, with solar activity leading the way.

    I expect all this to take place soon, as soon as the peak in solar cycle 24 passes on. Once we get rid of this peak we should have a very very subdued sun for years and years, and the impact this time will be greater, due to the fact this solar setup started way back in Oct. of 2005. The atmosphere today is much more susceptible to a subdued sun then it was back in 2005, due to the seven odd years of solar activity much below average.

    The climate system is nonlinear which means a very small change in some parameters(the sun) can cause great qualitative differences in the resulting behavior (chaos)of the climatic system.

    Much of the time the net climate feedback is NEGATIVE,which will neutralize amplifying POSITIVE FEEDBACKS, unless the forcing grows to a point from the POSITIVE FEEDBACK,that it takes over, at which point it gets to EXERT its explosive amplifying effects on the climate system, until something puts it in check, but it is in that in BETWEEN TIME, when the abrupt changes in the climatic system take place.

    I say that the SUN will be the source of the POSITIVE FEEDBACK, which will allow the force of that POSITIVE FEEDBACK ,to take over to one degree or another,the net NEGATIVE FEEDBACK in earth’s climatic system, that will cause the climate to go into some varying degree of a climate regime change, for some defined time.

    The sun will cause this to take place, due to a slight drop off in solar irradiance, UV light intensity drastically reduced, a much weaker solar wind allowing more cosmic rays to enter into earth’s atmosphere etc etc., which will then create the secondary effects, such as atmospheric circulation changes,more clouds ,more geological activity etc etc.

    When I read other explanations for the climate to change , such as changes in the THERMOHALINE CIRCULATION, or GEOMAGNETIC JERKS, they to me can’t explain the many temperature changes that have occurred throughout earth’s climatic history, let alone the recent MAUNDER MINIMUM and DALTON MINIMUM. They may be a consequence of the changes earth undergoes due to solar activity changes,(or solar activity changes itself). They may follow ,but they do not lead the climate into another regime change in my opinion, they are the result and not the cause . Again geomagetc jerks being a consequence of solar changes,,just to emphasize my point..

  108. In the above is what I have to say about our present situation, and this also can be applied to PAST
    cold periods such as the YD.

    There are to many past changes in temperature to have the source of this change be nothing other
    then the sun. The sun is the only source that exhibits enough change often enough, that can be tied
    into all the past temperature changes on earth. There is no other source.

  109. agfosterjr says:

    Steve P says:
    June 20, 2012 at 11:52 am

    In general the game species that survived were smaller and faster than the others, and tended to be of Eurasian origin. Why bison survived and horses didn’t, I don’t know, and neither do you. I challenge you to come up with any detail this species discrimination through catastrophe. I repeat, the K/T event did discriminate by size as much as behavior. Most of the little critters were wiped out too.

    Dennis Cox says:
    June 20, 2012 at 11:22 am
    Some of the denials of the YD impact event are getting ludicrous.
    ==============================================================
    Same goes for you. No food for horses? What did the buffalo eat? Why did island animals survive better than continental dwellers? The meteors avoided islands? Nothing about your nebulously defined theory makes any sense. How big was it? Why didn’t it affect Africa? Or Antarctica? Or did it? Let me remind you that the K/T even was as devastating to marine as to terrestrial species. Use your head now and tell us, does the fact that insular species fared better than continental species favor meteoric or human causes? Why were South American species decimated and New Zealand species unaffacted–until humans arrived?

    This silly nonsense can only thrive in vastly ignorant minds. –AGF

  110. Gail Combs says:

    timetochooseagain says: @ June 19, 2012 at 9:42 pm
    …………..
    The Milankovitch theory is too successful to justify throwing it out completely.
    ________________________________________
    Yes especially since Gerald Roe got the kinks out of the theory by using the rate of change in the Ice.

    Luboš Motl discusses the paper HERE.

  111. Dennis Cox says:

    agfosterjr says:

    “This silly nonsense can only thrive in vastly ignorant minds.”

    Hmmm…

    Those “vastly ignorant minds” have sure been producing, and publishing a lot of work.

    In Europe: Tian et al, 2010 went searching for diamonds in the YDB (In Europe it is also referred to as the Usselo Horizon) in Belgium. They wrote that “our findings confirm, and in fact reveal more direct proof than the earlier studies, the existence of diamond nanoparticles also in this European YDB layer No such particles are found in the overlying silt and clay or in the underlying fine sands.”

    Van Hoesel A, Hoek W, Braadbaart F, van der Plicht H, Drury MR. (2011) Nanodiamonds and the Usselo layer. Paper #1556, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland, reported finding “carbon aggregates [consistent with] nanodiamond” in YD-aged sediments In the Netherlands.

    Abstract from Marshall W, Head K, Clough R, Fisher A. (2011) Exceptional iridium concentrations found at the Allerød-Younger Dryas transition in sediments from Bodmin Moor in southwest England. Paper #2641, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland. Elevated iridium values, dated to start of the Younger Dryas cooling event, have been found in sediments deposited at a number of Late Glacial sites in North America and one in Europe. It has been proposed (e.g., Firestone et al., 2007, PNAS 104: 16016-16021) that this widespread iridium enrichment signal is the result of an explosive disintegration of a large extraterrestrial object over North America around 12,900 cal. yr BP, and it is contended that it was this event which instigated the Younger Dryas cooling. This scenario is controversial, and the ‘ET’ explanation of these geochemical signals is not universally accepted. This notwithstanding, we report here the finding of an iridium anomaly in the Allerød-Younger Dryas boundary sediments at Hawks Tor in the southwest of England. The concentration of iridium and other elements is determined in peat monoliths using ICP-MS, operated in collision-cell mode, and ICP-OES instruments. We find an increase of over 300 % in the iridium concentration measured in the bulk sediment immediately above the Younger Dryas boundary compared with the values found below the transition. The iridium-titanium ratio is used to confirm a lag between the start of the iridium enrichment and the timing of abrupt environmental disruption at the site signalled by decreases in the organic carbon content, and changes the concentrations of potassium, iron and manganese. These geochemical changes coincide with a shift from a humified peat to a minerogenic lithology. By using a new calibration of existing 14C ages, integrated with new AMS dates and optically stimulated luminescence ages, we show that the timing of this iridium enrichment found in southwest England is in agreement with the dates proposed for the iridium enrichment signals previously found in North America and Belgium.

    In Germany: Wolfgang Roesler et al., Carbon Spherules With Diamonds In Soils

    In South America: Mahaney WC, et al. (2010a) Evidence from the northwestern Venezuelan Andes for extraterrestrial impact: The black mat enigma. Geomorphology, v. 116, iss. 1-2, p. 48-57.

    Mahaney WC, Krinsley D, Kalm V (2010b) Evidence for a cosmogenic origin of fired glaciofluvial beds in the northwestern Andes: Correlation with experimentally heated quartz and feldspar. Sedimentary Geology, v. 231, iss. 1-2, p. 31-40.

    Mahaney WC, David Krinsley, Kurt Langworthy, Kris Hart, Volli Kalm, Pierre Tricart and Stephane Schwartz. (2011a)Fired glaciofluvial sediment in the northwestern Andes: Biotic aspects of the Black Mat. Sedimentary Geology. 237, (1-2), pp73-83

    Mahaney, WC, Dave Krinsley, James Dohm, Volli Kalm, Kurt Langworthy and J. Ditto. (2011b) Notes on the black mat sediment, Mucunuque Catchment, northern Mérida Andes, Venezuela.. Journal of Advanced Microscopic Research, vol. 6, no. 3.

    And on the North American Continent Firestone RB, et al. (2007) Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proc Natl Acad Sci USA 104:16016–16021.

    Baker DW, Miranda PJ, Gibbs KE. (2008) Montana Evidence for Extra-Terrestrial Impact Event That Caused Ice-Age Mammal Die-Off. American Geophysical Union, Spring Meeting 2008, abstract #P41A-05.

    Fayek, M.; Hull, S.; Anovitz, L.; Haynes, V.; Bergen, L. (2008) Evidence of impact material and the extinction of the mega-fauna 12,900 years ago. American Geophysical Union, Fall Meeting 2008, abstract #PP13C-1469.

    Tankersley K. (2009) “Evidence of the Clovis Age Comet at Sheriden Cave, Ohio.” Midwest Chapter of the Friends of Mineralogy Symposium and Field Conference (Geology Department of Miami University, Oxford, Ohio, USA), 5 September 2009.

    Firestone RB. (2009) The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna, and Clovis Extinction, 12,900 years Ago. Journal of Cosmology (journalofcosmology.com) Kennett DJ, et al. (2009a)

    Shock-synthesized hexagonal diamonds in Younger Dryas boundary Sediments, Proc Natl. Acad. Sci. USA, 106 (31): 12623-12628. Kennett DJ, et al. (2009b)

    Nanodiamonds in the Younger Dryas boundary sediment layer. Science 323:94.

    Sharma M, Chen C, Jackson BP, Abouchami W. (2009) High resolution Osmium isotopes in deep-sea ferromanganese crusts reveal a large meteorite impact in the Central Pacific at 12 ± 4 ka. American Geophysical Union, Fall Meeting 2009, abstract #PP33B-06.

    LeCompte MA, Goodyear AC, Demitroff M, Batchelor D, Mooney C. (2010) An Independent Review of the Younger Dryas Extraterrestrial Impact Hypothesis and its Recent Re-Evaluation by Surovell et al. 21st Biennial Meeting of the American Quaternary Association (AMQUA). Laramie, Wyoming. (this was the rebuttal of Surovell et al that is cited in the Lake Cuitzeo paper)

    Andrei V. Kurbatov et al. (Journal of Glaciology, Vol. 56, No. 199, 2010) reported the ‘Discovery of a nanodiamond-rich layer in the Greenland ice sheet

    Scruggs, MA, Raab LM, Murowchick JS, Stone MW, Niemi TM. (2010) Investigation of Sediment Containing Evidence of the Younger Dryas Boundary (YPB) Impact Event, El Carrizal, Baja California Sur, Mexico. Geological Society of America Abstracts with Programs, Vol. 42, No. 2, p. 101.

    Wu Y. (2011) Origin and Provenance of Magnetic Spherules at the Younger Dryas Boundary. Thesis, Dartmouth College.

    Isabel Israde-Alcántara et al. (2012) Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis

    T.E. Bunch et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago by

    Bottom line: It has been conclusively demonstrated in publications in major scientific journals that the Younger Dryas Boundary layer is in fact a global impact layer the rivals the Cretaceous/Tertiary layer. 

    agfosterjr  says that “This silly nonsense can only thrive in vastly ignorant minds.”

    The thing is, every name on that list is a multiple PhD scientist who’s published their data in refereed ligature; and in very well respected journals at that. And the only thing we read from agfosterjr  in response to that data is the kind of off topic straw man arguments, and vulgar, insulting ad hominems that can only originate from a vastly ignorant mind.

  112. Dennis Cox says:

    agfosterjr says:

    “This silly nonsense can only thrive in vastly ignorant minds.”

    Hmmm…

    Those “vastly ignorant minds” have sure been producing, and publishing a lot of work.

    In Europe: Tian et al, 2010 went searching for diamonds in the YDB (In Europe it is also referred to as the Usselo Horizon) in Belgium. They wrote that “our findings confirm, and in fact reveal more direct proof than the earlier studies, the existence of diamond nanoparticles also in this European YDB layer No such particles are found in the overlying silt and clay or in the underlying fine sands.”

    Van Hoesel A, Hoek W, Braadbaart F, van der Plicht H, Drury MR. (2011) Nanodiamonds and the Usselo layer. Paper #1556, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland, reported finding “carbon aggregates [consistent with] nanodiamond” in YD-aged sediments In the Netherlands.

    Abstract from Marshall W, Head K, Clough R, Fisher A. (2011) Exceptional iridium concentrations found at the Allerød-Younger Dryas transition in sediments from Bodmin Moor in southwest England. Paper #2641, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland. Elevated iridium values, dated to start of the Younger Dryas cooling event, have been found in sediments deposited at a number of Late Glacial sites in North America and one in Europe. It has been proposed (e.g., Firestone et al., 2007, PNAS 104: 16016-16021) that this widespread iridium enrichment signal is the result of an explosive disintegration of a large extraterrestrial object over North America around 12,900 cal. yr BP, and it is contended that it was this event which instigated the Younger Dryas cooling. This scenario is controversial, and the ‘ET’ explanation of these geochemical signals is not universally accepted. This notwithstanding, we report here the finding of an iridium anomaly in the Allerød-Younger Dryas boundary sediments at Hawks Tor in the southwest of England. The concentration of iridium and other elements is determined in peat monoliths using ICP-MS, operated in collision-cell mode, and ICP-OES instruments. We find an increase of over 300 % in the iridium concentration measured in the bulk sediment immediately above the Younger Dryas boundary compared with the values found below the transition. The iridium-titanium ratio is used to confirm a lag between the start of the iridium enrichment and the timing of abrupt environmental disruption at the site signalled by decreases in the organic carbon content, and changes the concentrations of potassium, iron and manganese. These geochemical changes coincide with a shift from a humified peat to a minerogenic lithology. By using a new calibration of existing 14C ages, integrated with new AMS dates and optically stimulated luminescence ages, we show that the timing of this iridium enrichment found in southwest England is in agreement with the dates proposed for the iridium enrichment signals previously found in North America and Belgium.

    In Germany: Wolfgang Roesler et al., Carbon Spherules With Diamonds In Soils

    In South America: Mahaney WC, et al. (2010a) Evidence from the northwestern Venezuelan Andes for extraterrestrial impact: The black mat enigma. Geomorphology, v. 116, iss. 1-2, p. 48-57.

    Mahaney WC, Krinsley D, Kalm V (2010b) Evidence for a cosmogenic origin of fired glaciofluvial beds in the northwestern Andes: Correlation with experimentally heated quartz and feldspar. Sedimentary Geology, v. 231, iss. 1-2, p. 31-40.

    Mahaney WC, David Krinsley, Kurt Langworthy, Kris Hart, Volli Kalm, Pierre Tricart and Stephane Schwartz. (2011a)Fired glaciofluvial sediment in the northwestern Andes: Biotic aspects of the Black Mat. Sedimentary Geology. 237, (1-2), pp73-83

    Mahaney, WC, Dave Krinsley, James Dohm, Volli Kalm, Kurt Langworthy and J. Ditto. (2011b) Notes on the black mat sediment, Mucunuque Catchment, northern Mérida Andes, Venezuela.. Journal of Advanced Microscopic Research, vol. 6, no. 3.

    And on the North American Continent Firestone RB, et al. (2007) Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proc Natl Acad Sci USA 104:16016–16021.

    Baker DW, Miranda PJ, Gibbs KE. (2008) Montana Evidence for Extra-Terrestrial Impact Event That Caused Ice-Age Mammal Die-Off. American Geophysical Union, Spring Meeting 2008, abstract #P41A-05.

    Fayek, M.; Hull, S.; Anovitz, L.; Haynes, V.; Bergen, L. (2008) Evidence of impact material and the extinction of the mega-fauna 12,900 years ago. American Geophysical Union, Fall Meeting 2008, abstract #PP13C-1469.

    Tankersley K. (2009) “Evidence of the Clovis Age Comet at Sheriden Cave, Ohio.” Midwest Chapter of the Friends of Mineralogy Symposium and Field Conference (Geology Department of Miami University, Oxford, Ohio, USA), 5 September 2009.

    Firestone RB. (2009) The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna, and Clovis Extinction, 12,900 years Ago. Journal of Cosmology (journalofcosmology.com) Kennett DJ, et al. (2009a)

    Shock-synthesized hexagonal diamonds in Younger Dryas boundary Sediments, Proc Natl. Acad. Sci. USA, 106 (31): 12623-12628. Kennett DJ, et al. (2009b)

    Nanodiamonds in the Younger Dryas boundary sediment layer. Science 323:94.

    Sharma M, Chen C, Jackson BP, Abouchami W. (2009) High resolution Osmium isotopes in deep-sea ferromanganese crusts reveal a large meteorite impact in the Central Pacific at 12 ± 4 ka. American Geophysical Union, Fall Meeting 2009, abstract #PP33B-06.

    LeCompte MA, Goodyear AC, Demitroff M, Batchelor D, Mooney C. (2010) An Independent Review of the Younger Dryas Extraterrestrial Impact Hypothesis and its Recent Re-Evaluation by Surovell et al. 21st Biennial Meeting of the American Quaternary Association (AMQUA). Laramie, Wyoming. (this was the rebuttal of Surovell et al that is cited in the Lake Cuitzeo paper)

    Andrei V. Kurbatov et al. (Journal of Glaciology, Vol. 56, No. 199, 2010) reported the ‘Discovery of a nanodiamond-rich layer in the Greenland ice sheet

    Scruggs, MA, Raab LM, Murowchick JS, Stone MW, Niemi TM. (2010) Investigation of Sediment Containing Evidence of the Younger Dryas Boundary (YPB) Impact Event, El Carrizal, Baja California Sur, Mexico. Geological Society of America Abstracts with Programs, Vol. 42, No. 2, p. 101.

    Wu Y. (2011) Origin and Provenance of Magnetic Spherules at the Younger Dryas Boundary. Thesis, Dartmouth College.

    Isabel Israde-Alcántara et al. (2012) Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis

    T.E. Bunch et al. (2012) Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago by

    Bottom line: It has been conclusively demonstrated in publications in major scientific journals that the Younger Dryas Boundary layer is in fact a global impact layer the rivals the Cretaceous/Tertiary layer. 

    agfosterjr  says that “This silly nonsense can only thrive in vastly ignorant minds.”

    The thing is, every name on that list is a multiple PhD scientist who’s published their data in refereed ligature; and in very well respected journals at that. And the only thing we read from agfosterjr  in response to that data is the kind of straw man arguments, and vulgar, insulting ad hominems that can only originate from a vastly ignorant mind.

  113. Steve P says:

    agfosterjr says:
    June 20, 2012 at 10:03 am and 1:19 pm

    The scenario fits hunting extermination to a tee.
    [...]
    Why bison survived and horses didn’t, I don’t know, and neither do you.

    No, but you seemed to be arguing that humans hunted the mammoths to extinction. I simply pointed out that it makes no sense for humans to have killed off the biggest beasts, when there were plenty of smaller ones around.

    And maybe we should talk about the bone heaps a bit. As you may recall, on Anzhu Islands off the Russian arctic coast near 75°N 141°E, early Russian explorers and traders found not only heaps of mammoth tusks mixed in with rhino and bison bones, but the shattered remains of ancient forests as well.

    Do elephants commonly get stuck in the mud and drown in Africa or India? Remains of mammoths were found in the permafrost so commonly by native Siberians that the myth of the giant moles was invented to account for the mystery. It was thought the giant moles died while digging to the surface.

    Those vastly ignorant minds will get you every time.

  114. feet2thefire says:

    @leftturnandre June 19, 2012 at 2:02 pm:

    About the sudden warming at the onset of the Bolling ~14500 years Cal BP, there are even more problems here, since the major glacial retreat started a few thousend years earlier. The problem was recognised by Denton et al 2006 and they dubbed it the mystery interval.
    (Denton G.H., Broecker, W.S. and Alley, R.B., 2006: The mystery interval 17.5 to 14.5 kyrs ago, PAGES news, 2: 14-16.)

    So if there are more not understood problems here, is it possible that one or more of our fundamental suppositions is fundamentally wrong?

    Always this is the case. Even data and artifact evidence gets interpreted “fundamentally wrong” sometimes, so basically when there is a puzzle it can be from as yet inadequate research or from dead end interpretations that lead down blind alleys.

    Also that quote: ” Evidence of Younger Dryas advance of continental ice sheets is reported from the Scandinavian ice sheet, the Laurentide ice sheet in eastern North America, the Cordilleran ice sheet in western North America, and the Siberian ice sheet in Russia.

    There was no Siberian ice sheet during the last glacial maximum.

    Good catch on that. I noticed it, too.

    This is an assumption most people make, that there were ice sheets extending down roughly equally in both western AND Eastern hemispheres. Not quite so. Notably the mammoths were where the ice sheets were NOT. Yet they ended up UNDER/IN the permafrost. One has to ask, How does that happen? Did sedimentation overcome them suddenly? Obviously not, and therein lies the real question: How did they get under the frozen soil?

    Let’s not forget that Darwin himself considered the extinction of the mammoths in northern Siberia to be an unsolvable puzzle.

    Steve Garcia

  115. agfosterjr says:

    Dennis Cox says:
    June 20, 2012 at 2:17 pm

    That’s quite a biblography–have you read any of it? Can you answer any of my questions? We know meteors collide and are capable of doing damage–if they land on cities. They haven’t yet; space junk is more likely to. So look; we’ve got different arguments getting mixed up in your head which you need to sort out:
    1) The possibility of a good sized meteor some 12 or 12ky. (quite possible)
    2) The possibility that it was big enough to affect cliimate. (quite improbable)
    3) The possibility that climate change wiped out the megafauna. (improbable)
    4) The possibility that meteors wiped out the megafauna. (quite absurd)

    You might want to read the literature which applies to the last category and see if you can respond to my challenge. Specify your version of the theory and explain to us the timing and distribution of Pleistocene extinctions. Tell us why mammoths survived on Wrangell Island till 4ky, why buffalo survived, giant ground sloths and horses didn’t, etc. If you can’t answer those simple questions you believe in a silly fairy tale, silly bibliography notwithstanding. –AGF

  116. rgbatduke says:

    The solar periodicity seems to be around 500 years as per MWP to LIA to date and the thermohaline circulation is around 1000 years.

    Over time they drift in and out of phase sometimes offsetting and sometimes supplementing one another.

    Um, with these periods they would be “drifting in and out of phase” every — 1000 years. As these periods are integer multiples of one another. Also, the transitions observed have timescales as little as 40 to 50 years, which is almost insanely fast as far as climate is concerned. That’s not consistent with “drifting” into resonance.

    But then, we don’t really know all of the timescales of solar variability, or the causes of same. Solar dynamics is difficult. I’ve started to study it just a bit (e.g. Landscheit’s paper, a Studies in Geophysics e-book, and other resources as I can find them. A big part of the problem is that a lot of interesting “stuff” happens in the deep core of the sun where dynamics is simultaneously enormously energetic and “fast” and yet constrained by density and hence “slow”. There are some very long term cycles there that we have no easy way to observe — neutrinos are pretty much the only probe that reaches in to where the action is, and beyond that we have models.

    So I don’t disagree with the assertion that the short timescale fluctuation out of ice age conditions over a trivially short time might require a solar effect or some other global driver, but I do disagree with the assertion that we can even heuristically peg this to known/observed solar cycles. However, there are some really exotic possibilities out there — the passage of the solar system through a moderately dense tendril of a cloud of interstellar medium (one with a density above an estimated critical threshold on the order of 10^5 H_2’s per cubic centimeter) would be enough to significantly modulate solar luminosity due to the gravitational energy of the infalling materia, and is also dense enough to diffuse downward into the thermosphere and actually invert the Earth’s usual loss of hydrogen while binding up O_3 into OH and H_2O. This could also alter climate in several ways — increase its bond albedo at a very high altitude, for example.

    The difficulty is that many of the exotic possibilities a) violate no known physical laws, that is, they are “plausible”; and b) don’t provide much in the way of a unique paleontological signature. I’d even add c) cannot be either confirmed or rejected on the basis of local observational evidence. We have less than a century of direct measurements from, and of, space. Ruling out astrophysical/solar causes for major climate variations is extremely difficult with so short a baseline and such a crude understanding of the underlying physics and contributory data.

    I do really like this article on the YD though. I was not aware of the possible weakness in the sudden dilution/thermohaline argument. Whether or not the moraine data is clear enough to positively refute this, it seems sufficient to make me doubt it more than I was doubting it, which in turn raises the plausibility of alternative explanations including solar variability or the more exotic ones.

    rgb

  117. rgbatduke says:

    Do elephants commonly get stuck in the mud and drown in Africa or India?

    During the monsoon in India, it is far from unknown. The floods the monsoon can cause can be sudden and fearsome. Not so often “in the mud” but in a river bed that was nearly dry that suddenly becomes a deep pool with unclimbable sides.

    (I used to live there — stories of elephant death of this sort are recorded in e.g. the writings of Jim Corbett and other naturalists and hunters during the British Raj, although I have no doubt that a more current search would turn them up too.)

    rgb

  118. IT IS NOT A METEOR, IT IS NOT A COMET AND IT IS NOT AN ASTEROID THAT CAUSED THE YOUNGA DRYAS. END OF STORY. THAT IS PURE NONSENSE..

  119. IT IS SOLAR VARIABILITY THAT WAS THE PROBABLE CAUSE OF THE YD. SOLAR VARIABILTY HAS BEEN UNDER ESTIMATED ,UNTIL VERY RECENTLY.

    [No need to shout. ~dbs, mod.]

  120. Gail Combs says:

    ferd berple says:

    “Cut human population from 7 billion back to a more sustainable 7 million. Otherwise, we are all doomed to die within the next 100 years..” [he forgot the /sarc]
    _________________________
    Dennis Cox says: @ June 19, 2012 at 11:38 pm

    So what’s your preferred method of mass murder to accomplish the culling of a few billion people without ruining the environment for those who remain? And who decides who get’s taken out?
    _______________________
    Agenda 21 of course and who gets tthe privilege of breeding? Well the Bureaucrats have that all figured out too.

    Why to you think governments such as the UK and the USA are taking DNA samples from all babies and storing those samples indefinitely? Why do you think RFID tags for livestock, drivers licenses, passports are being implemented? Why do you think there is a big push for Universal Health Care?

    Want to go to the doctor? Better have your implanted RFID tag or no care, want a job, want to buy food, clothing… Think I am making this up out of whole cloth??

    Potential Uses of RFID
    ….Identification of patients and hospital staff

    In July 2004, the US Food and Drug Administration issued a ruling that essentially begins a final review process that will determine whether hospitals can use RFID systems to identify patients and/or permit relevant hospital staff to access medical records. Since then, a number of U.S. hospitals have begun implanting patients with RFID tags and using RFID systems, usually for workflow and inventory management. There is some evidence, as well, that nurses and other hospital staff may be subjected to increased surveillance of their activities or to labor intensification as a result of the implementation of RFID systems in hospitals.The use of RFID to prevent mixups between sperm and ova in IVF clinics is also being considered.

    In October 2004, the FDA approved USA’s first RFID chips that can be implanted in humans….

    RFID tagging of patients has already been tested. Babies DNA is already taken and stored and the USDA has already funded development of a successful spermicidal corn.

    References:
    USA: Baby DNA and Newborn Screening

    The Citizens’ Council on Health Care has released a report in 2009 that raises concerns about the extension of eugenics into State newborn screening programs.

    UK: DNA database created from babies’ blood samples: Millions of newborn babies have had their DNA stored by hospitals without the proper consent of their parents, it has been revealed.

    National DNA database ‘worth discussing': NSW Minister

    Hospitals tune in to RFID: Testing gives way to implementation

    RFID-based Information System for Patients and Medical Staff Identification and Tracking

    .A small California biotech company, Epicyte, in 2001 announced the development of genetically engineered corn which contained a spermicide which made the semen of men who ate it sterile.

    The corn has been field tested in tests financed by the US Department of Agriculture along with a small California bio-tech company named Epicyte. Announcing his success at a 2001 press conference, the president of Epicyte, Mitch Hein, pointing to his GMO corn plants, announced, “We have a hothouse filled with corn plants that make anti-sperm antibodies.
    Epitcyte was bought out by a privately held company in Pittsboro, North Carolina. A bio tech company. Biolex

    And into the “Woo-Woo” or WHO conspiracy type stuff:

    Want a connection between the WHO and eugenics? ~ Vaccines

    Vaccines: Sterilisation & Abortion

    It should be noted that a population study in Africa turned up “strange statistics”

    Demographic Change in Sub-Saharan Africa (1993)

    In Chapter 2, Barney Cohen reviews levels, differentials, and trends in fertility for more than 30 countries from 1960 to 1992. He finds evidence of fertility decline in Botswana, Kenya, and Zimbabwe, confirming the basic results of the DHS. What is new here though is his finding that the fertility decline appears to have occurred across cohorts of women at all parities, rather than just among women at middle and higher parities, as might have been expected on the basis of experience in other parts of the world. He also presents evidence that fertility may have begun to fall in parts of Nigeria and possibly in Senegal.

    And also noted that the UN was in favor of Eugenics.

    1975 `Endangered Atmosphere’ Conference: Where the Global Warming Hoax Was Born

    Eugenics and the Paradigm Shift

    Mead’s population-control policy was firmly based in the post-Hitler eugenics movement, which took on the more palatable names of “conservation” and “environmentalism” in the post-World War II period. As Julian Huxley, the vice president of Britain’s Eugenics Society (1937-44), had announced in 1946, “even though it is quite true that radical eugenic policy will be for many years politically and psychologically impossible, it will be important for UNESCO to see that the eugenic problem is examined with the greatest care and that the public mind is informed of the issues at stake so that much that now is unthinkable may at least become thinkable.” Huxley was then director-general of the United Nations Educational, Scientific, and Cultural Organization (UNESCO).

    And a last couple of studies:

    The evolution of racial differences in intelligence Source : Mankind Quarterly, Fall/Winter91, Vol. 32 Issue 1/2, p99, 23p (condensed here) by Richard Lynn, University of Ulster, Coleraine, Northern Ireland

    SUNY @ Albany press release: Global Warming Could be Reversing a Trend that Led to Bigger Human Brains

    It is rather frightening how all this hangs together is it not?

  121. agfosterjr says:

    Rivers flowing to the Arctic Sea are always freezing up, creating ice dams and preventing flow to the ocean. Ice periodically forms over enormous stretches of the river basins, the dams break, floods sweep away mammoths and lay sediment over the ice, vegetation grows on the sediment, mammoths graze, ice melts beneath the sediment, mammoths fall through, etc. On islands mountain dust accumulates on snow packed into ice, moss grows, mammoth graze, ice crevasses form, mammoths fall into crevasses, sometimes concentrated like Antarctic meteors. It’s no great mystery.

    If you limit your list to the 48 states like Faith and Surovell you miss most of the important data. What F&S show is when temperate Amerinds finished off the big beasts. The Russians have a corner on pertinent evidence, but the big beasts died on the ice primarily in two stages over a period of tens of thousands of years, not all of a sudden. –AGF

  122. rgbatduke says:

    “Drop a 60-ton bolide on top of a mile of ice and you won’t find any crater after the ice melts. You’ll get a whale of a lot of water vapor, though…”

    This sort of event is pretty ignorable. Not even a whale of a lot of water vapor — there just isn’t that much energy. Assuming escape velocity for a collision speed, a metric ton of mass (1000kg) has a collision energy of:

    E \approx (1000) (10^4)^2 = 10^{11} Joules

    (Ignoring factors of 2). Which is really a pretty small amount of energy — the heat of vaporization is \sim 2 \times 10^6 joules/kg, so you’re only talking about vaporizing 10^5 kg of water, around five meters cubed.

    If you want “interesting” events, consider the explosion of Mount Tambora: http://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora. It was estimated to be the equivalent of just under a gigaton of TNT (800 Mt, 3 \times 10^{18} joules) and ejected 160 cubic kilometers of pyroclastic ash (pulverized earth) into the air. The sound was heard at least 1600 miles away. And that’s just the largest explosion in recorded history. Given two such events — Krakatoa was comparable, although roughly 4x smaller — in 200 years, it is reasonable to guestimate that 100 Mt volcanic explosions occur on a century timescale, with outliers that can be 10-100 times more violent. These explosions are more violent that the collision of a small asteroid — a 1 km in radius asteroid is has a mass order of Llatex 10^{10}$ kg, making the kinetic energy released quite comparable to Tambora at around a Gt (which failed to cause extinction-level climate change). It takes a big asteroid — one 10 km in radius — to give you the 1000-fold increase in energy released and push you out into extinction territory, at least as far as I can tell with my back of the envelope estimates.

    rgb

  123. Re : agfosterjr – Nobody argues that the extinctions didn’t involve remote outlier populations, while everyone more or less agrees the North American continental megafauna extinctions where synchronous and geologically instantaneous. The species that survived where either smaller, more numerous and much more mobile.

  124. Dennis Cox says:

    In response to agfosterjr:

    Yes, of course I have read them.

    My own radical theory of what happened back then is well expressed on my blog. It’s rather lengthy, and off topic to the subject of this thread. Which is the possible climatic effects of the event. My own thrust is the theoretical geomorphology, and planetary scarring it may have produced. If anyone is really interested they’re welcome to take a look.

    The only argument I am making here is that the YDB layer is in fact, a global impact layer that rivals the K/T boundary layer. I have made no other assertions, or claims as to the other effects the event that produced it might have caused.

    And in light of your previous, and continued small minded, and insulting ad hominems I see nothing whatsoever to gained by dignifying any of your straw man arguments with any further response.

  125. rgbatduke says:

    IT IS NOT A METEOR, IT I S NOT A COMET AND IT IS NOT AN ASTEROID THAT CAUSED THE YOUNGA DRYAS. END OF STORY. THAT IS PURE NONSENSE..

    Without shouting, I mostly agree. For one thing, there would be a signature in the dust layer associated with the event that I recall is lacking to ambiguous. There were — as I also recall — a number of other features to the YD — a prolonged drought in the US, dust storms hundreds of years long — it seemed to be a rather violent event with some very odd climate features. Well worth studying, well worth not drawing premature conclusions from as one studies.

    rgb

  126. rgbatduke says:

    the Gothenburg geomagnetic field excursion (13 000–12 000 years ago) http://www.sciencedirect.com/science/article/pii/003358947790031X
    may also be of interest

    It is, although paywalled. I will use my superhuman magic powers to get it for free shortly. Difficult to try to form a hypothesis linking the two events, but the timing is certainly interesting.

    rgb

  127. Gail Combs says:

    salvatore del prete says:
    June 20, 2012 at 12:16 pm

    The reason for the YD cold period and the 8200 years ago cool period and all other cool periods and warming periods is due to VARIATIONS in solar activity. The sun drives the earth’s climatic /oceanic systems, therefore any change it may undergo will have an impact on those systems.

    I will follow with a more detail explanation of how this may all come about…..
    _____________________
    Perhaps Anthony can post it as a separate thread. You can submit it here: http://wattsupwiththat.com/submit-story/

  128. agfosterjr says:

    Dennis Cox says:
    June 20, 2012 at 3:27 pm

    DC refuses to answer some very basic questions (I guess he never thought about them). Does any other catastrophist care to explain why the mammoths survived on northern islands? –AGF

  129. Gail Combs says:

    rgbatduke says:
    June 20, 2012 at 3:29 pm
    ……There were — as I also recall — a number of other features to the YD — a prolonged drought in the US, dust storms hundreds of years long…..
    __________________________________________
    And those hundreds of years long droughts and dust storms , not to mention the increase in fires, could easily wipe out the mega-fauna. What was not wiped out by starvation could have been hunted to death by predators including humans. Humans, having the ability to think and adapt survived, where as the mega-predators who were too specialized died out. However agfosterjr, insistence on blaming humans exclusively is typical of the “mankind hating” types who can never see anything but “evil humans” as the cause for every ill.

  130. Does any other catastrophist care to explain why the mammoths survived on northern islands

    Sure, while I don’t consider myself a catastrophist, whatever that is, I do acknowledge that catastrophes do occur on an almost regular if unpredictable basis. Remote outlier populations were isolated for the most part from human predation and far removed from the mostly continental and hemispheric effects of the Younger Dryas chronozone, and adapted to their dwindling range and food supply by a great reduction in size. It happened to humans as well.

    Seriously, this is one of the best understood aspects of all of this. I’m wondering why you and you alone seem to be having a problem with this particular aspect of the megafaunal extinctions, completely independently of the causation. If you have anything lucid to contribute, please do so.

  131. Smokey says:

    Thomas Lee Elifritz,

    May I give you a shoutout for your blog? I notice there are no comments. That’s a shame.

  132. Grey Lensman says:

    Dennis Cox Nails it. The grey area is the exact dating and I believe that has been marked and should be looked at for confirmation/adjustment.

    Wrangle Island Mammoths. That is easy to explain. Siberia is huge, a few specimens to the south survived the onslaught. As conditions improved they moved north. During the Holocene warm period, the tree line was much further north, and they roamed over ranges that included wrangle Island. Then as temps fell and food supply dwindled, they got smaller and they then ran out of habitat and died. This rapid dwafism process is well known

    In the USA, the resultant firestorm was not universal, pockets were left intact and thats were smaller species survived. Luck playing a part. Also the Southern boundary is more constrained than that in Siberia with a vastly different natural climate. Thus the different survival profile.

    The mythological 40 days and 40 nights of rain is a recorded reference to the vast amounts of ice sheet vaporized and returning to earth. That alone would have had massive impacts, including washing away a lot of evidence.

  133. markx says:

    Off topic, I know, but mentioned above in other comments:

    Re the shrinking human brain capacity: with the recent knowledge that some caucasians and asians have about 4% neanderthal genes, (and some denisovian genes), is there a possibility that as we ‘dilute out’ that proportion by interbreeding …. we lose brain capacity (neanderthals had bigger brains….)…??

    Cannot for the life of me see how it could relate to global warming – (do the Inuit have really big heads?)

  134. Grey Lensman says:

    I recently saw pictures of the USA dust bowl event. Horrendous. Imagine something ten times worse( and it has happened many times before). Suggest somebody who knows about it posts a picture collage. That will provide sobering images.

  135. Dennis Cox says:

    It’s off topic. But I’m sorry, I jus’ gotta respond to this one.
    On the subject of brain capacity: We have an African Grey parrot here with a brain that’s smaller than a peach pit. And some great big dogs with brains that weigh more than that whole damn bird. Yet the bird is infinitely more inteligent than any of the dogs. And she has a vocabulary.

    Moral of the story: Brain structure is more important than brain size. And brain size is no indicator of brain “capacity”.

  136. markx says:

    Dennis Cox says:June 20, 2012 at 7:56 pm

    “…the bird is infinitely more intelligent than any of the dogs. And she has a vocabulary…”

    I think you may be correct there … I saw a documentary on a parrot study… it could count up to five and combine its vocabulary to describe things, usually food. The trick dogs have is to understand human body language, and know where we are looking, and what our gestures mean.

    Re human brains, probably we need to redefine our terminology; I guess I was shortcutting….
    I suspect it is correct to say, in relation to humans, that there may be little connection between brain size (cranial capacity) and cognitive ability.

    But really, I was not entering into that discussion, I was only commenting on the fact that there are reports that the ‘cranial capacity’ of the modern human is about 150 cc LESS than that of humans of 20,000 years ago. (and that some have proposed it may be linked to AGW).

    I find it difficult to envisage a mechanism…..

    http://discovermagazine.com/2010/sep/25-modern-humans-smart-why-brain-shrinking/article_view?b_start:int=2&-C=

  137. HenryP says:

    salvatore del prete says
    Mainstream has their heads in the sand, and the SETUP is in place and has been in place for at least 3 years to cause this climate regime we are currently in, to finally change into another climate regime. Now when I say change into another climate regime ,that does not necessarily mean a drastic drop in temperatures, but what it means is the temperatures will decline ,and it won’t be gradual, it will be in quick jerks and these jerks could be as small as .2C to as much as 2.0 C, but the jerks themselves will be fast,although the magnitude of jerks in temp. will depend on how the items that control the climate phase in with one another, with solar activity leading the way.

    Henry says
    we are agreed on that it is cooling, but according to my latest apparent mathematics the rate of cooling is very predictable and slowly on parabolic curves…..polynominals of the 2nd order.

    http://www.letterdash.com/henryp/global-cooling-is-here

    You can calculate exactly at what rate we are cooling. Currently it is -0.08 K per annum (on the Means).
    no jerks and jumps – I can calculate exactly at what rate each year we are cooling .
    However, it seems that everyone here and everywhere else seem to be in denial that it is cooling since 1994, so obviously one day they might pick on the ways of their errors (in global temp. measurement) in which case it might look like there are big jumps…..

    Otherwise I note that you do not show us any measurements or any analysis of data that would seem to support the things that you claim.

  138. phlogiston says:

    Dennis Cox says:
    June 20, 2012 at 11:22 am
    Some of the denials of the YD impact event are getting ludicrous.

    One can explain the extermination of the giant animals by recognizing what effect the event must have had on the food supply.

    Much of the edible biomass of North America would have been burned away down to the last blade of grass.

    The bigger you are, the more you need to eat every day. The animals that survived the impact event and didn’t face extinction were simply those that didn’t need to eat so much.

    Most of the Mega fauna that went extinct after the event probably just starved. And with them went any specialist predators that depended on them for food.

    The biggest NH megafauna extinctions (e.g. wooly rhino, N American wild horses) took place 30,000-40,000 years ago, well before the YD.

  139. rgbatduke says:

    The reason for the YD cold period and the 8200 years ago cool period and all other cool periods and warming periods is due to VARIATIONS in solar activity. The sun drives the earth’s climatic /oceanic systems, therefore any change it may undergo will have an impact on those systems.

    Evidence? This is an open question today, let alone then. I don’t disagree, mind you, I just don’t agree either until there is convincing evidence. I end up 2/3 or 3/4 convinced from time to time (because there is some evidence) but then somebody like Lief comes along and points out that the evidence is not consistent and hence might be coincident, and then there is the pesky problem of the mechanism(s).

    There are theories — with some corroborating evidence — that the sun is long period variable with a periodicity of 300 or 600 My and that this drives ice ages. There are other theories — with some corroborating evidence — that the sun bobs up and down and passes through both the galactic plane and spiral arms and that this modulates the GCR rate which in turn modulates the climate, e.g. —

    http://www.sciencebits.com/ice-ages

    There are verified physical mechanism whereby GCRs “can” modulate albedo, and these mechanisms may or may not feed back on top of more mundane feedback mechansims such as the vastly simpler one Willis is proposing, that when it gets warmer the tropics respond with more thunderstorms which increase the cooling rate both by transporting moist heat up to where it is more efficiently lost and by reflecting incoming sunlight, for a net negative feedback to any forcing. Then there is the aforementioned possibility that both the Sun’s brightness and the chemistry of the Earth’s atmosphere could be modulated by means of passage of the solar system through the interstellar medium, which is not uniform in density (and whose local density is basically unmapped AFAIK). There are seriously unknown phenomena, such as the effect of a large CME that hits the Earth, or a series of such CMEs.

    As Lief I think just obliquely pointed out, there is the Earth’s magnetic field itself! As it wanders around it alters the geographical pattern of cosmic ray protection and might well nonlinearly feed back into climate. This got me thinking about pole strength variation as well, but attendez — the northern magnetic pole has been moving steadily north across Canada since the early 1800s!:

    http://science.nasa.gov/science-news/science-at-nasa/2003/29dec_magneticfield/

    The field has also weakened by 10% or so over that time (according to this article). We are thus left with yet another thing that is strongly correlated with the Earth’s temperature increase over the same time — one could try to construct a model where strong fields are net cooling, and where net cooling is globally more efficient the closer the poles are to the equator. Hence moving the north pole further north is net warming. Weakening the global field strength is net warming. Both of these together could — note that I say could, I haven’t constructed a plausible mechanism and am not asserting that there is one, we are still at the correlation stage searching for causality — be responsible for some fraction of the observed warming since the early 19th century.

    The problem isn’t with finding correlations between cosmic, solar, and geological phenomena that could be responsible for some fraction or even “all” of the observed fluctuation in global temperature. Such correlated phenomena abound! Worse, there is absolutely nothing that prevents them all from affecting global climate, in a nonlinear and coupled way!

    This latter easily explains why there is no perfectly correlated “signal” between e.g. solar state and temperature, between CO_2 and temperature, between ENSO and temperature, between anything and temperature. A solar maximum is net warming, except when it’s not because some magnetic, aerosol, decadal oscillation, thermohaline, or greenhouse gas (in any combination!) trump it. So we are constantly trying to resolve signal from not-quite-noise, resolve a one-to-one causal relation when in reality that is as difficult as detecting the true killer of Julius Caesar (which knife was it that did the job, when there were so many at work?).

    We are constantly looking for a smoking gun. What if there are smoking guns, in the hands of demented dwarves that roll dice before firing in nearly random directions?

    I will follow with a more detail explanation of how this may all come about…..

    And I eagerly await it, but bear in mind that it will just have to stand in line with all of the other postulated causes and observed near-coincidences in the data. People on list hate models, but in the end one really does need a highly multivariate model that can manage all of this even to test a complex set of hypotheses. The human brain wants it all to be simple: “The Sun modulates the Earth’s Global Temperature” or “CO_2 modulates the Earth’s Global Temperature”. But what if it is the Sun, CO_2, the Sun’s magnetic field, the Earth’s magnetic field, the state of the ocean, the phase of the decadal oscillations, the particular positioning of the continents as they drift about, the phase of the Earth in a complex dance of axial tilt, orbital eccentricity, and axial precession, the location of the solar system as it plows through an unmeasured interstellar medium, the number of active volcanoes and the number of those volcanoes that explode (or worse, just erupt for a few tens or hundreds of thousands of years a la supervolcanos like Yellowstone) with Gt+ energy release per century, deforestation, and let’s not forget asteroids and Dr. Evil’s diabolical device (a.k.a. the great unknown). All of these could be significant contributors, and they could be intertwined and could reinforce or partially cancel one another, depending on their nearly completely independent or even random periods or phases.

    People just don’t get it. This is a hard problem. One simply cannot solve it by looking at a window 100 years, 200 years, or 500 years long. Bob Carter has the right of it — one needs to start by looking at global climate over geological time to start to understand what the range of natural variation is, and frankly, until one can understand the longest time scale variations first and systematically working one’s way down to mundane timescales one hasn’t a friggin’ prayer of understanding the shortest time scale variations. We know this because we have clear evidence, unexplained, of enormously rapid changes in global temperature that have nothing to do with anthropogenic CO_2, at least. How can we possibly exclude the possibility that the mechanism responsible for those rapid changes isn’t alive and well and working today, and is responsible for the not even particularly rapid changes we observe today, especially when the geological evidence is such that not one person on Earth would look at the geological variation of global temperature, point to the end, and say “Oh my, look at the runaway warming!”

    Quite the contrary. They’d go to sleep, because the present isn’t even close to being extreme. It is boringly normal.

    rgb

  140. HenryP says:

    rgb says:

    http://wattsupwiththat.com/2012/06/19/the-intriguing-problem-of-the-younger-dryaswhat-does-it-mean-and-what-caused-it/#comment-1014565

    Henry says:
    You say a lot of things but you do not bring anything to the table. All is speculation.
    I say:

    http://www.letterdash.com/henryp/global-cooling-is-here

    from where you should be able to understand from all three curves, for maxima, means and minima, that warming is long gone. In fact it stopped in 1994/5.
    That being the case (for me it is fact)
    brings us all back to the Orssengo Curve

    His actuals also show a marked cooling from 1994. If you want to know where that graph came from, look here:

    http://wattsupwiththat.com/2010/04/25/predictions-of-global-mean-temperatures-ipcc-projections/

    The only thing about the Orssengo graph that seems a bit wrong to me is that he thought the maximum of warming would be around 2000. I see it a bit earlier. So the graph may have to be shifted a little to the left. However, either way, I don’t see anything disastrous yet on the horison although I did buy some extra warm cloths. Making wars and exploding (atomic) bombs does seem to be a cause for extra cooling. (note the blue areas in the graph and the one simple error on the scale)

  141. Stephen Wilde says:

    rgb,

    All reasonable points but whatever the factors affecting the Earth’s energy budget at any given moment the netted out effect at that moment is represented in the average sizes, positions and intensities of the established permanent climate zones.

    Look to them to see what is going on.

    Poleward / zonal jets and widened Hadley cells occur when the troposphere is warming.

    Equatorward / meridional jets and smaller Hadley cells occur when the troposphere is cooling.

    Lots of varied evidence supports that simple proposition.

    Then rank the potential factors in order of scale and it is clear that sun and oceans are magnitudes ahead of everything else with all the other factors usually cancelling each other out most of the time.

    We need to establish the characteristics of the air circulation at the point where warming switches to cooling and vice versa.

    There was such an inflection point in the mid 70s and I aver there was another around 2000.

  142. agfosterjr says:

    Gail Combs says:
    June 20, 2012 at 4:11 pm
    ” However agfosterjr, insistence on blaming humans exclusively is typical of the “mankind hating” types who can never see anything but “evil humans” as the cause for every ill.”
    =======================================================================
    On the contrary, absolution of human involvement in “overkill” is simply a perpetuation of the “noble savage” ideology: the ancients were worthy caretakers while we moderns destroy all. Moreover early humans possibly contributed to massive deforestation by accidental or intentional fire setting. The literature is replete with stacked decks favoring the innocent hunters; e.g., that a small fraction of remains contain a spearheads, when of course those animals that were killed by Clovis hunters were dismembered, and spearheads removed.
    _________________________________________________________________________
    Grey Lensman says:
    June 20, 2012 at 7:14 pm
    ========================
    You explain nothing. The island dwellers are the most vulnerable of all, having no place to escape or migrate to. And it was impossible for mainland beasts to escape to the islands after the sea rose; the “dwarf” mammoths were there before and after YD. Whatever one’s explanation for megafauna extinctions, island extinctions generally are those most certainly attributable to human causes–not necessarily through hunting, but also by introduction of dogs, pigs, agriculture, fire and disease.
    _________________________________________________________________________
    phlogiston says:
    June 21, 2012 at 5:07 am

    “The biggest NH megafauna extinctions (e.g. wooly rhino, N American wild horses) took place 30,000-40,000 years ago, well before the YD.”
    ========================================================================
    Not sure where you get that–the horses lasted till about 12kya, and probably the rhinos too.
    __________________________________________________________________________

    It’s bad enough blaming the climate when the ice ages were 3 million years old. It’s reasonable and necessary to take tectonics into account, and many early migrations and extinctions are attributable to the appearance of the Panama and Bering Strait bridges. Even if humans crossed much earlier, their Arctic technology was lacking, but they and their dogs were probably responsible for some of the earlier extinctions. But the appearance of Clovis hunters spelled doom for the mainland mammoths and a host of other species. Climate cycles make for a very poor excuse, and meteors make a very poor excuse for climate change. So meteors are improbable times improbable as extinction causes. It’s not just island mammoths, it’s South American giant armadillos, ground sloths, etc.

    The pattern is clear: those animals with the longest history of familiarity with humans fared the mesolithic revolution the best. Those surprised by the upstarts fared worst. Those on the most remote and vulnerable islands lasted the longest, in spite of having nowhere to escape to. It took the humans a while to find them. –AGF

  143. beng says:

    ****
    rgbatduke says:
    June 20, 2012 at 3:29 pm

    IT IS NOT A METEOR, IT I S NOT A COMET AND IT IS NOT AN ASTEROID THAT CAUSED THE YOUNGA DRYAS. END OF STORY. THAT IS PURE NONSENSE..

    Without shouting, I mostly agree. For one thing, there would be a signature in the dust layer associated with the event that I recall is lacking to ambiguous.
    ****

    Depends. If most or all of the proposed impacts were airbursts, especially if occurring over ice-sheets (and comets are mostly ices), there would be little dust. Most of the “debris” would be vaporized ice. The metallic remains of the impactors would be the only dust, and I think some of the proposed “sites” show traces of iridium, etc.

  144. HenryP says:

    Stephen Wilde says
    There was such an inflection point in the mid 70s and I aver (sic) there was another around 2000.

    Henry says
    Yes, looking at my curve for the means, it does look like things changed sign from cooling to warming around the beginning of the seventies (42 years ago) and again from warming to cooling 16.4 years ago, counted from before 2011 (the last complete record we have is from 2011)

    But where did you get your information from?

  145. rgbatduke says:

    You say a lot of things but you do not bring anything to the table. All is speculation.
    I say:

    http://www.letterdash.com/henryp/global-cooling-is-here

    from where is sou should be able to understand from all three curves, for maxima, means and minima, that warming is long gone. In fact it stopped in 1994/5.

    Dearest Henry,

    You need to learn the difference between curve fitting and a theory, and the difficulty of extrapolating a fit curve as a predictive model. I am (I would humbly claim) a serious expert in modeling and fitting any smooth curve to a short trend in data and extrapolating it as if it is meaningful is an elementary mistake, one that will cost you your shirt if you use it either in climate science or the stock market.

    If you want to actually understand something of the problem, read Koutsayannis paper: Nonstationarity versus scaling in hydrology

    http://itia.ntua.gr/en/docinfo/673/

    (Note well to everybody: This is an all time classic paper, and one that I strongly recommend that everybody grab and peruse. Figure 1 should be mandatory “reading” for every single person involved in climatology. It is also the original paper, as far as I can tell, on what will IMO end up being the most important contribution to statistical climatology of all time (so far) — the observation of a clear statistical scaling law in climate fluctuations and the consequent inference of Hurst-Kolmogorov dynamics. This might allow us to build working stochastic GCMs, or at least to clearly understand their mode of, failure, in the next decade. Other Koutsayannis papers and presentations are equally brilliant.)

    So Henry, when you learn that there is more to predictive modelling than fitting smooth functions through data in some arbitrarily selected window and hoping/expecting it to extrapolate out of the window, I’d be happy to continue the converstation, but the Koutsayannis paper above, figure 1, illustrates better than any words why that approach, unsupported by an actual dynamical model that generates the supposed fit functions, is almost certainly mathematical nonsense with no real predictive value.

    rgb

  146. Steve P says:

    The Earth’s surface being 71% water, most impacts would be in or over the oceans, with perhaps titanic tsunamis following in their wake. It is thought that the Taurid complex was formed about 30,000 years ago from the break-up of a comet. Reasonably well-preserved mammoths have been turning up in the permafrost since antiquity, and some date to more than 40,000 years ago, while others are more recent. No doubt, a big enough flood can sweep all in its path, and there are other mechanisms for huge floods without considering impacts or tsunamis, but the problem of preservation remains, and such is showcased by Lyuba from c41,800 whose remains were found on the Yamal peninsula, of all places.

    ‘Not to discount the several other b’ars in the woods noted by RGB, above..

  147. rgbatduke says:

    Depends. If most or all of the proposed impacts were airbursts, especially if occurring over ice-sheets (and comets are mostly ices), there would be little dust. Most of the “debris” would be vaporized ice. The metallic remains of the impactors would be the only dust, and I think some of the proposed “sites” show traces of iridium, etc.

    I don’t disagree; this is the “ambiguous” part. The problem is that there is no “smoking gun” layer of iridium a la the Cretaceous extinction boundary, so there is little reason to infer a dino-killer scale asteroid as a cause. Also, much smaller asteroids could leave an ambiguous trace of iridium without actually affecting climate. Finally, see my discussion of energyeven a 2 kilometer wide asteroid (or an equivalent distribution of smaller asteroids) would be unlikely to have a greater impact than Tambora. Of course this doesn’t make the hypothesis untenable, because the climate is multvariate, we had just pulled out of the ice age, and the climate may have been unstable so that even a small perturbation triggered a cold transition then where Tambora failed to in 1815. But it does make it less plausible.

    So I will have to stick with “I think I agree” that the cause of the YD isn’t likely to be meteors or falling asteroids because of a lack of convincing evidence, while acknowledging that an absence of evidence isn’t evidence of absence, and that even evidence of presence does not suffice to establish causation. I liked the freshwater interrupting thermohaline circulation argument because it was a good explanation of the timescale of the NH transition, and because the global thermohaline conveyor belt is one of the things that I do believe could even today quickly put the Arctic and Northern Europe into the deep freeze. The synchronicity of NH and SH cold transition argues against it, but it doesn’t necessarily argue for an asteroid either.

    One of the very simplest hypotheses is a solar event, but corroborating evidence is tough to find. Another might be a truly massive volcano explosion, say 10-100 gt, with consequent global tsunamis (sinking of “Atlantis” sort of thing). But replacing the volcano with 4 km asteroid (about the right scale) would change little, except that in the case of an asteroid one would really expect the iridium signature to be consistent, clear, and global. That’s a lot of asteroid, after all. A volcanic explosion, OTOH, would have little in way of a global signature — a dust layer, which is at best what we’ve got, although resolving THAT is tough.

    FWIW, it has its own wikipedia page — it can summarize the arguments better than any of us here on list (and includes the criticisms):

    http://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesis

    Basically, there is evidence of an impact in North America (in North Carolina where I live, actually, where the layer is clearly visible in eroded stream beds). The platinum group mineral content of the layer is inconsistent. The microdiamond content is consistent. The megafauna extinction pattern is inconsistent (and difficult to explain with any simple hypothesis). Overall, I think the inconsistents have it, although there may have been some other non-asteroidal major geological event that occurred at the same time as the YD and may or may not have triggered it. I just don’t know enough about the geology to know what is excluded.

    rgb

  148. agfosterjr says:

    Primitive man was mostly vegetarian and insectivorous, gradually becoming omnivorous. The further north they moved the more exclusively carnivorous they became, at least in winter. Those who crossed the Bering Strait were fishing and hunting specialists, having to turn almost exclusively to hunting at the expense of fishing as they moved inland, and having to learn vegetables from scratch as they moved southward. Feeding a clan required the most efficient hunting: the best hunters went for the biggest game, enabling the most rapid population growth. Clovis hunters increased at the expense of the mammoths, and when they were gone the Clovis hunters disappeared too.

    Then the Folsom hunters flourished, going after the biggest game still left, the giant bison. It didn’t matter where a big game animal lived outside the tropics, if it was big it was in trouble. Giant wombats went extinct; little wombats didn’t.
    Giant beaver went extinct; little beaver didn’t.
    Giant ground sloths went extinct; little ones didn’t.
    Giant bison went extinct; little ones didn’t.
    Giant cameloids went extinct; little ones didn’t.
    Gyptondon went extinct; little armadillos didn’t.

    For totally unrelated reasons big mammoths went extinct and little ones didn’t–till later. Why was size a disadvantage? Because the hunters went for the biggest prey, the easiest meat for the most people. Big beaver have just as easy a time finding food as little beaver; big wombats as little wombats, big bison as little bison. Hunting preference is the deciding criterion. Climate hardly registers on the scale. Meteors don’t register at all. –AGF

  149. Stephen Wilde says:

    HenryP asked:

    “But where did you get your information from?”

    In the 60s and 70s I kept my own records (long since disposed of) in anticipation of monitoring the expected cooling that everyone was banging on about back then.

    Contrary to my expectations I saw more frequent southerly and westerly winds developing from the mid 70s onwards with a warming trend especially in the winters.

    Many years later it was confirmed as the 1976 – 78 Climate shift which appears now to be well accepted..

    Anyway, that led me to keep an eye on the warming trend but in a more informal fashion due to career and family committments and around 2000 I noted the whole thing going into reverse and that reversal continues to this day. I started talking about it on blogs some 4 years ago and have built a plausible climate theory on the basis of it.

    To my mind all the new data is confirming my hypothesis but there has not yet been a long enough period of time to constitute proof.

    Nonetheless I have put it out there and await developments with interest.

  150. HenryP says:

    rgb says
    I am (I would humbly claim) a serious expert in modeling and fitting

    Henry says
    the paper you quote actually confirms that my approach was correct/
    initially, when I found missing data at a weather station, for a month, I put in the long term average, which is the generally accepted statistical principle for such a problem. However, when measuring temps. and climate versus time that was the wrong way to go.
    I explained this here

    http://www.letterdash.com/henryp/global-cooling-is-here

    Note that I determined not only the development of means, but also those of the minima and maxima, which, for some reason are ignored by all in climate science. All can be transformed into parabolic curves with r square >0.95
    on the maxima it is r2=0.995
    So, the probability that I am wrong with my assertions and predictions is only 0.5%
    You want to take a bet on that?

  151. rgbatduke says:

    OK, so that reply either went in partially or disappeared. To try again:

    Of course I’d take a bet ten years out. It’s nearly a sure thing, because you are completely clueless about what R^2 measures as far as extrapolating a fit trend is concerned (basically, nothing).

    Are you familiar with: Taylor Series, the Stone-Weierstrass theorem, how both together guarantee that you can fit nearly any smooth function with a parabola in a sufficiently local neighborhood, and how that fit will fail for almost all possible smooth functions (all the ones that aren’t really parabolas) once you try to extrapolate outside of that neighborhood and cubic or higher order terms become important, and how even that doesn’t serve to explain the problem with using this in climate science, where transitions appear to be smooth nearly flat variations punctuated by sudden jumps on a decadal plus timescale (Hurst-Kolmogorov transitions).

    Did you even glance at the Koutsoyannis reference I linked? Of course not, or I wouldn’t be explaining the problem to you, as his figure 1 shows how a parabola for a short sample interval becomes a linear trend for a longer one becomes a sinusoidal for a still longer one and (not shown) how all of this could still be nearly irrelevant patterned noise on a still longer timescale?

    I could take a few thousand lines and explain statistics or modelling to you. Or you could take a course and learn what R^2 really means for extrapolation versus interpolation. Hmmm, I vote for the latter.

    rgb

  152. Steve Wilde, and myself have been in pretty good agreement about the solar variability and how that in turns effects the climate through solar changes themselves. I take it further, by trying to show the secondary effects from those solar changes.
    Those secondary effects, again being as follows:

    ATMOSPHERIC CHANGES – A MORE -AO/NAO, WHICH RESULTS IN MORE CLOUDS,SNOW COVER ,PRECIP., WHICH RESULTS IN A HIGHER ALBEDO /LOWER TEMPERATURES.
    ATMOSPHERIC CHANGES DUE TO OZONE CONCENTRATION CHANGES IN THE ATMOSPHERE IN THE VERTICAL /HORIZONTAL, DUE TO UV LIGHT CHANGES FROM THE SUN.

    VOLCANIC ACTIVITY INCREASE(ESPECIALLY HIGH LATITUDE,THIS IN TURN WILL HELP PROMOTE A MORE -AO ,IN ADDITION TO THE LOW SOLAR ACTIVITY. SO2 ACTING AS A COOLING AGENT FOR EARTH’S SURFACE AND WARMING AGENT FOR THE STRATOSPHERE

    HAVOC WITH EARTH’S MAGNETIC FIELD – MORE COSMIC RAYS ,MORE CLOUDS, MORE VOLCANIC ACTIVITY.
    . A sun that displays variability changes, seems to effect earth’s magnetic field by weakening/strenghtening it,in very fast ,sharp ways..

    SOLAR WIND DECREASE- ALLOWS MORE COSMIC RAYS MORE CLOUDS

    PDO- EVIDENCE OF A 60 YEAR CYCLE ASSOCIATED WITH SOLAR ACTIVITY

    ENSO- BEING GEARED MORE TOWARD LA NINAS RATHER THEN EL NINOS WHEN PDO IS IN COLD PHASE WHICH MIGHT BE TIED INTO SOLAR ACTIVITY.

    SOLAR IRRADIANCE ITSELF DECREASING AT TIMES OF LOW SUNSPOT ACTIVITY.

    I think what is not being appreciated or understood by the mainstream is the fact that solar variations are much more common and have a greater degree of magnitude/duration(change/staying power) then what the present thinking is. In addition the secondary effects from these solar changes are not being taken seriously enough and are much greater, then what mainstream present thinking is.

    If one just studies the two most recent solar minimums those being the DALTON ,and MAUNDER MINIMUMS, one can see the same changes took place with earth’s climate each time, both BEING associated with low solar activity.

    I say those two periods of low solar activity can be exceeded in magnitude and duration , and have been in earth’s past, creating a much greater change in the climate, then what even happened during the DALTON/MAUNDER MINIMUMS.

    I say the variabilty of the sun and how it effects items that control the climate are being greatly underestimated.The typical 11 year sunspot cycle is NONSENCE, and that is what mainstream is fixated on. When the sun does display an 11 year sunspot typical pattern of course nothing is going to happen, because the sun is changing in a regualr pattern ,which cancells itself out.

    Here we have mainstream trying to put upon the public that, that is the norm, which is flat out wrong. Mainstream in addition, is also trying to down play the EXTREME solar activity that has taken place prior to 2005, going back to 1850 , which I say is 100% responsible for the temperature rise last century.

    Here we are in 2012 , and the sun has had a significant change which started in year 2005. Lag times have to be appreciated ,but I say once this solar max.of cycle 24 passes on by(which is very very weak) that is when the impacts of the quiet sun on the climate will start to exert themselves.
    If the study of LIVINGSTON, and PENN ,should come to be, that could mean this GRAND MINIMUM can be much more severe then anticipated, and the climatic effects that much more.

    TEMPERATURE CHANGES

    Past histroy shows the temperatures do not change gradually, they go in jerks both up and down. The only time temperatures change gradually is when the climate is in one particular climatic regime. I say led by the sun, and through the secondary effects, if duration of time,magnitude of change is strong enough, thresholds will be met which will then cause the climate to shift into another climate regime,jhence the sharp temperature changes, during those times.

    If it is not the sun ,I say what is it?????

  153. EARTH’S MAGNETIC FIELD – A weak magnetic field is associated with cooling of the earth, while a strong magnetic field is associated with a warming earth. Somebody had this backwords. It has been shown that earth’s geomagetic field increases by a factor of 3 to 5 times in strength during interglacial periods.

    The above all make sense if one things an increase is cosmic rays/more clouds plays a big role in the climate. The weaker the solar magnetic field is ,along with earth’s magnetic field, the more cosmic rays will be allowed to enter into earth’s atmosphere .Hence a cooling during periods of waek magnetic fields both on the sun and earth..

    The SURPRISE , for lack of a better word is the sun has SPURTS of activity within the minimum most likely ,and that is when charged particle burst from the sun are greatest, and with earth’s magnetic field already in a weakened state ,their effects are much greater then would be otherwise. I think the charge particle burst to earth’s magnetosphere ,play a role in an increase in geological activity here on earth, if the bombarment of the particles occurs when the sun is mostly in a solar minimum state.

    This is why in large part there is always an increase in geological activity here on earth, in association with prolong solar minimum periods. Look at the Dalton,Maunder minimums as an example .

  154. HenryP says:

    Henry@rgb
    clearly, you must be able to understand that I calculated all three parameters, maxima, means and minima, finding they all best fit into polynominals of the 2nd order, at r2>0.95
    which cannot possibly be co-incidental….
    That means I can use the highest 0.995 found for maxima to determine cut off points for warming and cooling in time.
    I suggest you go back to your stats classes…
    please donot patronize me.
    if you have some evidence to prove I am wrong, show me your (actual) data. Otherwise, please just go to bed.. which is what I am going to do now.
    you are just confusing everyone here and you really have no data to show……all you have is words and endless speculations….

  155. El Gordo says:

    Okay,

    I’ll bite.

    The answer is… Drumroll….
    Cosmic Ray incursion and deformation of the heliosphere resulting in varying levels of cosmic energy absorption throughout the solar system.

    Why hasn’t it happened since?
    Well, we don’t know enough about interstellar space to predict timing of these things.
    But, if this theory were true, it could happen again tomorrow.

  156. phlogiston says:

    agfosterjr says:
    June 21, 2012 at 7:44 am

    phlogiston says:
    June 21, 2012 at 5:07 am

    “The biggest NH megafauna extinctions (e.g. wooly rhino, N American wild horses) took place 30,000-40,000 years ago, well before the YD.”
    ========================================================================
    Not sure where you get that–the horses lasted till about 12kya, and probably the rhinos too.

    I was wrong, mis-remembered an article I recently read in Science Illustrated. A series of megafauna extinctions began 30-40,000 years ago with the likes of sabre toothed tigers and mastodons but the mammoths (10.500 yrs), north American horses (10,500 yrs) and wooly rhinos (14,000 yrs) continued till the start of the Holocene.

  157. phlogiston says:

    Eske Willerslev, a geogeneticist at Copenhagen University, studied genetic diversity, geographic ranges and diet of several megafauna from 50,000 years ago till the Holocene. The picture that emerged is that the animals which becme extinct at the Holocene has already been in decline for at least 20,000 years. This decline was largely attributable to reducing habitat and climate change (deepening glaciation). In the final centuries before extinction competition caused by overlap between different megafauna with similar diet (as shown by gut and fecal material) and also overlap with humans and human hunting, both may have contributed to the final extinction. However the species in question, e.g. mammoth, wild horses, wooly rhinos, had already been in decline for thousands of years.

    http://www.nature.com/news/2011/021111/full/news.2011.626.html

  158. rgbatduke says:

    EARTH’S MAGNETIC FIELD – A weak magnetic field is associated with cooling of the earth, while a strong magnetic field is associated with a warming earth. Somebody had this backwords. It has been shown that earth’s geomagetic field increases by a factor of 3 to 5 times in strength during interglacial periods.

    Right, but if you read the context of my remarks (and followed the link to the NASA site that presents the evidence) you would see that the Earth’s magnetic field has grown 10% weaker during the recent warming trend (in addition to moving North, closer to the rotational pole and away from the equator). This was offered to support the observation that it is easy to find phenomena correlated with temperature change that may or may not be causal of that change. It is also direct, immediate, current evidence that your assertion that a weak field is associated with cooling is not, at the moment, true. Whether or not it is true “on average”, or whether the magnitude of the change is simply too small to be relevant — all of that requires a concrete model. I merely offer the locally confounding example.

    Similarly, if one looks at solar maxima and minima, while there are some coincidences and some of them appear to be strong enough that one really, really wants to believe them causal, there are both maxima and minima that don’t seem to produce the predicted effect. It’s not a single variable system. It may well be a matter of solar state AND magnetic state AND greenhouse gas levels AND recent volcanism AND the state of the ocean AND… with all of them contributing, reinforcing or cancelling, any given local warming or cooling trend. And we don’t have any idea which of these parameters — if any — are in any sense dominant, the primary determinant(s) of global temperature (whatever that means) or climate (ditto). Aside from Mr. Sun being the source of basically all of the heat and radiation, in the end, being the source of all of the balancing cooling. That part is easy enough, or would be if it weren’t for the modulation by albedo, greenhouse gases, water vapor (so interesting it really has to be treated separately), and (again) a long line of …’s

    Forgive me if I’m just as skeptical of skeptical models for the Earth’s climate as I am of the GCMs. Maybe more. GCMs, for better or worse, at least try to be quantitative and make falsifiable predictions. They turn out to be wrong, sure, but that doesn’t mean that any particular alternative formulation that makes CO_2 less important and solar state more important is righter, only that until you make it into an actual model, it can’t be falsified in turn.

    The problem is that whether or not one “likes” modelling, for a problem this complex one either throws one’s hands into the air in disgust and pronounces it unsolvable (not a completely unreasonable thing to do, as I suspect that it still is) or one tries to capture what one thinks might be the most important science in a model and see how it does when compared to nature. Sadly, this sort of approach is isomorphic to nonlinear parametric function fitting, and in the end all too often turns into the moral equivalent of what I’m chiding Henry for — fitting a (short) range of the data only to learn that however well you can make the fit work on the training set it generally doesn’t extrapolate out of the training set to any sort of non-interpolatory trial set. It is, however, superior in that one can at least assign some meaning to the (possibly failing) set of model parameters, and hence learn something — perhaps — from even the model failures.

    rgb

  159. agfosterjr says:

    phlogiston says:
    June 21, 2012 at 1:22 pm

    The link is typical of the silliness: the last glaciation or deglaciation presented the big beasts with unprecedented challenges and left the little critters unaffected. Never in the history of the world has extinction been almost exclusively size dependent, and no theory I’ve seen besides human hunting explains this unique occurrence. If heat did in the mammoths then pity the poor polar bears. –AGF

  160. High solar activity trumped the weakening magnetic field which caused the temperatures to rise last
    and cosmic ray levels to be low.

    I cannot find any examples of temperatures rising on the earth when solar activity was low, or
    cooling when solar activity was high.

  161. This change in solar activity to very low levels , which started in 2005 and should last for sometime to come ,in my opinion will tell us very soon just how much influence or lack of influence, the sun exerts on earth’s climatic system.

    Again I say the sun drives earth’s climatic/oceanic systems, therefore if something changes from the source(the sun) that drives the systems , it stands to reason, those changes must effect the systems it drives.

    The sun has gone from very active (prior to 2005) to very inactive after 2005. I can’t believe the forces the sun exerted on earth’s climatic system (along with all the secondary effects) will not change due to the significant change in the solar activity.

    Again the Dalton and Maunder Minimums lend support to what I am saying.

    Time will tell.

    One thing I know for sure, and that is, it is not a trace gas with a trace increase that controls the climate. The CO2 hoax, is just that, a hoax.

  162. rgbatduke says:

    finding they all best fit into polynominals of the 2nd order, at r2>0.95
    which cannot possibly be co-incidental….

    Until you understand why this statement would make any mathematician laugh out loud, you will continue to be ignored by mathematicians and physicists and statisticians. Until you look at Koutsoyannis paper — which you clearly still haven’t done — you won’t understand why even math novices that have done so will doubt your results. Nor will you understand why Roy Spencer (who puts a third order curve through his UAH global troposphere temperatures, and who I’m sure did so long before you did) carefully prefaces this with the remark that the curve is drawn only as a guide to the eye and is not intended to imply meaning.

    I’m not being patronizing, I’m trying to teach you. If you are completely confident that your understanding of math and statistics is superior to everybody else in the Universe, by all means refuse to be taught. You might well ask if I have any justification for believing that I am qualified to teach you (given that we’ve never met and for all I know for certain you could be a double Ph.D. in math and statistics). So here are my credentials. I have a BS in physics, a BA in philosophy, have completed enough math courses for a major in that as well but all but two taken as an undergraduate were at the graduate level so I’m probably closer to a masters level than either a BS or a BA. I am the author of dieharder, a random number generator tester (and hence am pretty buff in the general realm of hypothesis testing). I’m on my second company selling very high end predictive modeling services, the second one largely based on a patent (pending) on how to make inferences in both directions across a privacy boundary (or other constraint on exporting records in a general database) without violating any individual’s privacy (exporting their record) across the boundary, using a clever application of Bayes’ Theorem. I’ve worked on Monte Carlo (Markov Chain) models in physics for well over a decade, modelled Langevin processes in quantum optics, and done any amount of nonlinear curve fitting in between. I teach selected independent study students advanced statistics and statistical mechanics, and am writing a book extending the work of Richard Cox and E. T. Jaynes on how (Bayesian) probability theory is effectively the basis of all human knowledge.

    Now, listen up. The whole point of my referencing a Taylor Series is that it is a prescription for expanding any smooth function in the neighborhood of a point as:

    f(t_0 + \Delta t) = f(t) + \frac{df}{dt}|_{t = t_0} \Delta t + \frac{1}{2!} \frac{d^2f}{dt^2}|_{t = t_0} \Delta t^2 + \frac{1}{3!} \frac{d^3f}{dt^3}|_{t = t_0} \Delta t^3 + ...

    As you can see, any function f(t) that has a third derivative at a point t_0 that is smaller than \frac{\Delta t^3}{3!} is going to be well-fit by a quadratic function, just as on a smaller range it is decently fit by a linear function, on a still smaller range it is well fit by a constant, and on a still broader range it is decently fit by a cubic. One doesn’t get quite as elegant a result from Weierstrass:

    f(t) = a_0 + a_1 t + a_2 t^2 + a_3 t^3 +... = \sum_{i = 0}^\infty a_i t^i

    because one doesn’t get an elegant bound on the size of the a_i‘s but again it is pretty clear that if one puts one’s origin in the middle of any range of data and sets one’s scale so that all of the points in the range are less than one, the coefficients have to actually grow for the expansion not to be dominated by the first few terms.

    You wanted proof — this is a mathematical proof that your assertion in the first paragraph of this response is incorrect. It can be coincidental. In fact, for a small enough range of data compared to the true variability of the unknown function you are trying to fit it isn’t really coincidental, it is almost certain that a quadratic function will provide an excellent fit.

    Finally, as an assignment, you might try to learn something about R^2. I offer you the following quote from the wikipedia article to get you started:

    Notes on interpreting R2

    R² does not indicate whether:

    * the independent variables are a true cause of the changes in the dependent variable;
    * omitted-variable bias exists;
    * the correct regression was used; (this is one place you get in trouble)
    * the most appropriate set of independent variables has been chosen;
    * there is collinearity present in the data on the explanatory variables;
    * the model might be improved by using transformed versions of the existing set of independent variables.

    It also does not indicate whether or not any model can extrapolate unless you have a concrete basis for the model. As noted (and proven) above, given any smooth objective function f that is the centroid for some random scatter, for a sufficiently small sampling one expects to get first R^2 = 0 for a linear model (adequately fit by a constant), then R^2 \approx 1 for a linear model, then R^2 \approx 0 for a linear model but R^2 \approx 1 for a quadratic model, etc as you open up the range being fit, unless the error bars on the points being fit are so large that you can’t fit any linear or better model. And in all of these cases, one cannot be certain that the next higher neglected term doesn’t become dominant as soon as one is outside of the fit range! If you ever actually followed the link and looked at the Koutsoyannis paper, you could see, and understand, that at a glance.

    I won’t even go over the fact that fitting max, min, and mean (three parameters) with a three parameter quadratic model is also not surprising, because the discussion above is more elegant and apropos and besides, inevitable if you can fit the actual data nicely with a quadratic. It still doesn’t guarantee that the quadratic will extrapolate outside of the fit range.

    You can see this without even waiting for the future. Just try to extrapolate the quadratic backwards in time. See how quickly it departs from the data?

    rgb

  163. Robert Brown says:

    I cannot find any examples of temperatures rising on the earth when solar activity was low, or
    cooling when solar activity was high.

    Lief Svalgaard is your man. He’s got a zillion of them. Although it is really pretty easy to do — temperatures rose pretty steadily from the Dalton minimum up to the late 20th century right across significant variability in the solar cycle. Lief also offers evidence — take it or leave it, but he’s pretty serious — that the sunspot count in particular has been seriously abused as a measure of solar activity for the last 200 or so years and that corrected measures show far less correlation between solar activity and temperature (a lot of the correlation that exists comes from changes in the counting algorithm that basically found more spots compared to the earlier measures as the 20th century advanced, in coincidence with generally rising temperatures). If I understand his papers correctly — perhaps he’ll chime in (he usually does, if his name is invoked).

    I will note that this isn’t universally accepted — Ushokin and others use radiometric proxies to determine solar activity across the entire Holocene; their results do seem to support the hypothesis. But the main point is that finding or not finding (counter)examples depends in part where (at which solar activity representation and at which global temperature representation, given that THAT isn’t particularly reliable either) you look. It leaves the entire proposition at least somewhat dubious, although hardly disproven.

    If you want more evidence, it is hardly plausible that solar activity remained low throughout the entire 80,000 years of the last ice age. It may be an important local modulator of temperature — I suspect that it is, without agreeing that it is quite proven as things stand — and still not be an important global modulator. As, for that matter, may CO_2 be.

    rgb

  164. Robert Brown says:

    This change in solar activity to very low levels , which started in 2005 and should last for sometime to come ,in my opinion will tell us very soon just how much influence or lack of influence, the sun exerts on earth’s climatic system.

    And with this I agree. And I believe that you are right, and that temperatures are likely to drop as a consequence of the low activity. I like the model where some aspect (magnetic or otherwise) of solar activity modulates the climate nonlinearly. It is because I like it that I’m rigorously careful not to claim that it is proven or certain, especially while the only semi-reliable evidence of correlation in the period where we have semi-reliable measures is the bobble in temperature and solar activity in the 60s. I’ll be a lot more convinced if solar activity remains low in 24 and temperatures refuse to dramatically rise and actively fall once we pass the (low) peak, and then aggressively fall if 25 is as low as at least some people project that it will be.

    It will be equally interesting to see what happens to CO_2 during that interval. If global temperatures fall and CO_2 concentrations fall along with it, it will certainly strengthen the models of the Carbon Cycle that postulate that most of the growth in CO_2 observed over the last 35 years or so has come because of warming (which alters e.g. ocean and soil chemistry so that the equilibrium concentration is higher) rather than because of the anthropogenic contribution. After all, the ocean could easily take up all of the human contributed CO_2, as could the soil — both have one to two orders of magnitude more CO_2 bound up in them than the entire atmosphere and actively exchange enormous amounts of CO_2 with the atmosphere every year.

    That’s part of the problem. Things have been “boringly monotonic” over much of the last century. As I’ve been pointing out to Henry, monotonic low order linear or nonlinear models are too easy to fit and the fits are too meaningless to be of use. What is useful is a model where major variations in both directions correlate well between cause and effect. With luck, we’ll see some real variation of important (potential) control parameters and we’ll see some sort of real response.

    rgb

  165. Gail Combs says:

    El Gordo says:
    June 21, 2012 at 12:55 pm

    Okay,

    I’ll bite.

    The answer is… Drumroll….
    Cosmic Ray incursion and deformation of the heliosphere resulting in varying levels of cosmic energy absorption throughout the solar system.

    Why hasn’t it happened since?…..
    ______________________________________
    And then there are those who mention the Solar system bobbing in and out of the galactic plane.

    …Every 60 million years or so, two things happen, roughly in synch: The solar system peeks its head to the north of the average plane of our galaxy’s disk, and the richness of life on Earth dips noticeably.

    Researchers had hypothesized that the former process drives the latter, via an increased exposure to high-energy subatomic particles called cosmic rays coming from intergalactic space. That radiation might be helping to kill off large swaths of the creatures on Earth, scientists say.

    The new study lends credence to that idea, putting some hard numbers on possible radiation exposures for the first time. When the solar system pops its head out, radiation doses at the Earth’s surface shoot up, perhaps by a factor of 24, researchers found….

    http://www.space.com/10532-earth-biodiversity-pattern-trace-bobbing-solar-system-path.html

    That could also explain the wiping out of the mega fauna but not the sudden freezing with buttercups still in the mouth and undigested plant matter in the stomach found in some specimens.

  166. I don’t think you understand how the solar /climate ,connection works, or for that matter the
    climate system itself. If you had read carefully my previous post on why the climate might change,
    you would not have brought up the statement that temperatures went up after the DALTON
    MINIMUM, despite solar variability.

    When the climate is in a particular climatic regime all the items that control the climate from the
    sun,to volcanoes,to enso,to the pdo are going to result in random temperature fluctuations even
    if the same forcings are involved.

    What is needed is for thresholds to be met by the various items that control the climate in order to
    change it in one direction or another. This is not easy to accomplish,but when it happens it can
    be very abrupt.
    The sun ‘s variation per say is not going to change the climate or even correspond to temperature
    changes over the short run ,due to the endless feedbacks in the system to begin with and due to
    what state the climate system is in at any given time.

    How the climate changes is when THE POSITIVE FEEDBACKS that are created, are so strong that
    they overtake the negative feedbacks. How that is accomplished is ONLY if the duration and degree
    of MAGNITUDE change, in the items that controll the climate (let’s say the sun) are PERSISTENT
    enough and INTENSE enough to create a POSITIVE feedback in the climate system that can
    overwhelm the mostly negative feedbacks(which keep things in check most of the time),to cause the
    climate to shift into another range of temperatures or regime change.

    In order for solar variation to accomplish that POSITIVE feedback, it does not mean it does it, just
    by the fact that it varies. It has to vary by X amount ,for X amount of time in order to create the
    POSITIVE feedback through it’s variance that is strong enough to overcome the other negative feed
    backs in the climate system in order to exert it’s effects on the climate system.
    Also lag times have to be considered, especially the ocean which can, put off solar effects in the
    short run.
    LEIF ,may understand solar ,but I think he is lacking in the climate aspect of things.
    To put this in another way, I should have said I havesaid I never seen the temperatures rise when
    the sun was in a prolong deep minimum period or fall when the sun was in a very prolong active
    period.

  167. this site is notletting me write in it ,the way I want to.
    That aside, I say in order for the sun to have the climatic effects I refer to, the SOLAR FLUX,
    a measure of solar activity, has to stay at values of less then 90, and do so for many years.

    That only happens during GRAND MINIMUMS , which we are likely to have, going forward.

  168. HenryP says:

    rgb says
    It still doesn’t guarantee that the quadratic will extrapolate outside of the fit range.

    Henry@the Duke
    You should perhaps take some time to actually look at all my data.

    http://www.letterdash.com/henryp/global-cooling-is-here

    I don’t go outside the fit range. To calculate the change in signal from warming to cooling (e.g. on the maxima) I can go linear (r2=0.9645), I can go (nat) logorithmic (r2=0.9967) 0r I can go binominal (r2=0.9950). In all three cases, and staying within my measuring range, I find that when y=0 (when there was no warming or cooling) all 3 equations give me x=16.4 That means at 16 years BP the warming period ended and we changed to a cooling period (1994-5). In my case, 2011 is the “present”. When x=0 (that is 2011) we find the most reasonable result coming from the said binominal, namely -0.06 K per annum. On the linear it would be -0.04, on the (nat) logarithmic it would be -0.2K per annum –
    Similarly it can be shown that the means are now dropping by -0.08 K per annum. Means are now dropping a bit faster then maxima because maxima have been dropping for a longer time and earth is only now busy starting to play catch up.

    Now for getting these results, pray do tell, where did I go and extrapolate outside of my measuring range? I stayed within the 37 years where I measured. I only looked at the other side of the binominals for means and minima which suggests to me that another change at y=0 could have occurred at ca. 42 years BP and wanted to know from Stephen Wilde how he had figured that out.
    I did not proclaim that yet as a final result.

  169. Spector says:

    As Dr. Henrik Svensmark appears to have shown that there is a link between high cosmic radiation activity and cold weather periods on Earth, based on intervals when the Earth and the solar system were going through the spiral arms of the galaxy, where such radiation is high, I think it might be worthwhile to see if the Earth might have been transiting an unusual part of the galaxy during the Younger Dryas event.

    If this were, for example, the expanded remains of an ancient supernova, then there may also have been many embedded solid fragments, greatly increasing the probability of impact events during the transit interval.

    If true, this would really prove the Svensmark’s theory.

    Svensmark: The Cloud Mystery
    “Uploaded by rwesser1 on Jul 24, 2011″
    100 likes, 9 dislikes; 8,433 Views; 62:46 min
    “Henrik Svensmark’s documentary on climate change and cosmic rays.”

  170. SOLAR VARIABILITY VERSUS CLIMATE CHANGE
    One last time to explain where I am coming from in regards to this matter.

    In order to obtain a POSITIVE FEEDBACK,from a variance in solar activity, that has a degree of MAGNITUDE CHANGE powerful enough to bring earth’s climatic system to a THRESHOLD, I propose solar activity as measured by the SOLAR FLUX(NOT SUNSPOTS PER SAY)has to achieve a SOLAR FLUX reading of 90 or less, for a DURATION in period of time, for at least 10 years. Solar flux being at a reading of 90 or lower ,95% of the time.

    Once solar activity goes down to this level and stays at this level ,then and only then can the secondary effects from the prolong solar activity and the low solar activity itself PHASE IN, to exert enough of a POSITIVE FEEDBACK, to over come the inherent NEGATIVE FEEDBACKS of earth’s climatic system, to perhaps bring about an ABRUPT climatic change. Temperatures for instance going to a NEW RANGE,in a SHARP manner, in response to this.

    Right now we are in the same climate regime, all the small variations in temperature are more or less random events caused by the normal oscillations in the climate system, such as ENSO,PDO, or VOLCANIC ACTIVITY as examples. Nothing has changed or oscillated in the climate system including the sun up to this point enough, to bring about the POSITIVE FEEDBACK needed , to bring the climate to a THRESHOLD.
    I am hopeful that this GRAND MINIMUM ,which started in 2005,once it reaches it’s peak will be INTENSE enough,and LONG enough in duration to bring earth’s climatic system to some sort of a THRESHOLD, which will bring the temperatures down to another range. How much different a range I don’t know, for it will depend on how weak solar activity actually becomes, and how the secondary effects respond and phase in with this weakness.

    SOLAR ACTIVITY /COSMIC RAYS /GEOMAGNETIC FIELD

    There is a school of thought from what I can gather, that says if the difference in the charge between the sun and the earth is strong enough, it can cause a sharp weakening of earth’s magnetic field,thus allowing cosmic rays to flood into our atmosphere. This if it happens ,happens when the sun becomes very active, after being in a deep minimum state. The temperature response is sharply down at first, due to the influx of cosmic rays, only to reverse in time and rise sharply , as the solar wind establishes itself once again and starts to deflect the cosmic rays away from earth, while at the same time earth’s geomagnetic field recovers.

    If one believes in the cosmic rays,more clouds created ,lower temperature sequence, this is an interesting approach to help explain past abrupt temperature changes.

  171. Robert Brown says:

    Now for getting these results, pray do tell, where did I go and extrapolate outside of my measuring range? I stayed within the 37 years where I measured. I only looked at the other side of the binominals for means and minima which suggests to me that another change at y=0 could have occurred at ca. 42 years BP and wanted to know from Stephen Wilde how he had figured that out.
    I did not proclaim that yet as a final result.

    Good, because that is an example of what I’m talking about. And if you extrapolate your polynomial fit back 200 or 300 years, does it still fit the data? How about 1000 years, forward or backwards? Of course not, because your function becomes so negative that the Earth’s temperature would be negative, and negative temperatures don’t exist outside of lasers (and then, only for a special interpretation of the term “temperature”). So we agree that your fit has limited predictive value outside of the range in which it was fit. Now to find a reasonable value for that range.

    I would argue that a reasonable value is at most four or five years, even more reasonably one or two. Of course, I can’t really tell from your web page (which I’d looked at multiple times generating my previous responses) but it looks like you’re trying to fit only four data points — the temperature anomaly on a 37 year basis. Your method description leaves something to be desired, so let’s go through it. You use 45 weather stations taken randomly “from all over the world”, that weren’t missing a lot of data. This is a bit self-contradictory — “randomly” means that you use a random selection method to choose weather stations out of a very large pool. However, you obviously preselect them by eliminating from the pool stations with inadequate or missing records (a non-random process). Finally, the “all over the world” part is perplexing — random selection from most pools would yields a sample — especially one with only 45 elements — that is highly biased towards populated areas which and are hardly uniform. Generally, to select stations from all over the world uniformly one has to have a hightly NON random selection process as some parts of the world have only a handful of stations where others, e.g. the United States, are extremely dense in them.

    And then there are the oceans, which cover 70% of the Earth’s surface and are completely unrepresented by “weather stations”.

    So when you say random, do you mean:

    a) Handle all weather stations with data problems — in particular infilling (a process I absolutely hate, BTW — there are right ways and wrong ways to handle missing data and this is a very wrong way, as it is basically making stuff up in such a way that your error estimates are all horribly wrong from that point on — if you make error estimates).

    b) From what is left, select a large number of sites from geographical locations at different latitudes and longitudes that yield a uniform probability of covering the planet with a random selection process;

    c) Roll dice (or use a random number generator) to select out of this pool.

    or do you mean that you just did b), looked over a bunch of sites and grabbed one “at random” that didn’t have data problems. I ask because this latter process cannot be described as random. Unless you have an objectively random selection process, you should not use the term, and you should recognize that it is an opportunity for bias to creep in and/or for your work to be challenged. It has long been demonstrated that humans are almost incapable of generating random elements in any selection process. If you try to write down a random string of digits, it will almost certainly fail many tests of randomness. We make lousy random number generators!

    Second point — why are you working so hard? Woods For Trees will let you slice and dice and fit the last 40 years of data a few thousand different ways, all online, with far, far more data (and hence much more statistically meaningful results).

    Third point — I have no real idea of how you made your table, not from your description. In particular, how did you compute the number in each column labelled “Last X years”? You call them the “average change in temperature per year”. What does this mean? How do you compute it? In words it sounds like you are (per station):

    a) Forming the 37 year mean (from all of the data over all 37 years?).
    b) Subtracting the mean from the data to form the anomaly (for all 37 years) to form the temperature anomaly on a 37 year basis.

    So far this is all good, or at least reasonable, and very similar to what Roy Spencer does with his truly global, properly selected and averaged UAH lower troposphere data which is far, far better than yours, and which he also sometimes presents with a fit (as I noted) with a smooth curve for fun. You can see his data here:

    http://wattsupwiththat.com/widget/

    and even put a widget on your personal webpage that automatically updates the graph every month (Anthony doesn’t re-plot this page quite often enough, sadly, so it gets a bit out of sync with the actual widget:-(.

    Then you do not describe adequately how you form the average change per year during the period indicated. Do you:

    c) Take the anomaly for 37 years ago, divide by 37, and make that your first column, anomaly for 32 years, divide by 32, and make that second column, etc?

    c’) Take the anomaly for 37 years ago, subtract it from the anomaly for 36 years ago, divide by 1, make that the first column, etc?

    c”) Something else?

    The second of these is really “the slope” at 37 years ago, but what you are probably doing is akin to the first. I won’t criticize this at this point (although I could) except to note two things: Why 37, 32, 22 and 12 years? Why not 37, 36, 35…? Why vary the interval? Why not coarse grain the average so that the same number of samples contribute on both sides of a centroid, that is look at the change per year over a seven year interval and center the slope on the middle year? Both of these are serious flaws in your approach as year 37 MIGHT have been (and in fact was) anomalous in some way (in particular, it might have been sitting on or in the El Nino bobble clearly visible in the UAH data). Picking particular years in the set is yet another form of bias, intentional or unintentional.

    So then (AFAICT) you end up with the four columns of data, one entry per “randomly” selected, infilled station. Let’s focus on just one thing — the means. Your final product is:

    37 32 22 12
    0.015 0.013 0.014 -0.019

    You fit these four points — again, if I understand your method correctly, which I may not — to:

    y(x) = -0.00011 x^2 + 0.0067 x - 0.08240

    and claim an R^2 = 0.954.

    Here I’m a bit dismayed. First of all, none of these points have an error estimate or a standard deviation (whatever that might mean, frankly, for the method you are using). Goodness of fit estimate are thus almost completely meaningless. Of course you have the data and might have generated the s.d. for the means for each column, in which case you could have fit the data and generated Pearson’s \chi^2, which would have been at least moderately meaningful. Or perhaps you are fitting the entire table of data all at once in a routine that internally generates \chi^2 and R^2 (if so, what routine or toolset are you using?) How do you justify fitting the mean anomaly in this way given that different stations have very different temperature anomaly ranges (so that you automatically give the greatest weight to the stations with the greatest anomaly)?

    Here is where your using different intervals to compute the slope comes back to haunt you. When you divide by 37 you suppress the variation in the data by a factor of 3 compared to dividing by 12 (if you use method c) above). So the 12 year data is incorrectly weighted in computing error estimates.

    In the end, your table of data means above is obviously not quadratic, it has two local maxima and two local minima. Indeed, it could be fit exactly with a cubic — so why not use a cubic? Perhaps because the cubic gets warmer in the past? But how do you reject that possibility, since you have no a priori reason to choose a constant, linear, quadratic or cubic or fourth, fifth or fiftieth order polynomial (except that with only four points cubic is already perfect).

    Then you do something really odd. You assert that since your fit has zeros — two of them — “cooling has already begun” at the year corresponding to a zero in the fit range. Cooling compared to what? The 37 year mean? You note that (since your quadratic is upside down) there is another zero 42 years ago. Was the earth “cooling” 47 years ago? 60? 100?

    Of course not. And this is why your entire result is nonsense, or if not nonsense, nothing one cannot get faster, more accurately, and without the egregious claims by simply looking at the UAH data, well plotted, or looking at your own data for just the annual anomalies, well plotted, and without “selecting” particular years. Just plot the full dataset (scatter plot) or the means, per year, and please — compute the s.d. per year and include it as an error bar on the means for the year. Then fit your whatever to the full dataset — to the anomalies themselves, not to the “slopes” averaged over some variable interval. Compute \chi^2 for the fit, as it will be very revealing — if the error bars are as wide as the range of variation of the data from end to end of the plot, \chi^2 will be very small and so will R^2. If the error bars are small, \chi^2 will be much larger as a smooth low order polynomial fit will not interpolate the data particularly well, but a linear R^2 may be significantly different from 0, indicating a meaningful trend on the interval.

    Look, statistical analysis, and fits, aren’t “magic”. They can’t squeeze information out of noise, and most of the content of any given graph of temperature or (especially) temperature anomalies is noise! It is also very much a case of GIGO — garbage in, garbage out. There’s no reason to think that a quadratic fit to anomalies (even the strange ones you compute) should be more meaningful than a linear fit, or for that matter a constant over the interval. Every year the anomaly will, after all, be different from the mean and if you generated a completely random distribution of anomalies for the years involved with a given width around the mean, for a short enough interval you could most definitely fit a low order polynomial to the result, even when you know that the result has no meaning. It would have very, very small polynomial coefficients — just like yours does! Those small coefficients are a warning — you could be (and mostly, probably, are) fitting noise, not trend.

    That’s why most people stop with computing a linear trend over short baseline data. Even that is usually meaningless, but that’s your best chance for meaning. Quadratic curvature? Difficult to infer, especially when the means themselves are manifestly not quadratic over only 4 samples, and believe me, if you fit a cubic to the data you’d get completely different quadratic and linear and constant coefficients, a sign that the expansion is not systematically convergent. Getting a linear trend clearly distinguishable from no trend is usually considered — incorrectly — to tell you something about what might happen if one continues the trend to extrapolate the future outside of the interval.

    It’s incorrect because for short sample baselines, in climate science, the curves are never nice linear/smooth low order functions. Well, except for CO_2 concentration at the top of Mauna Loa — that’s a major exception to many rules. They are noisy as all hell, fluctuate up and down and sideways, have completely different “trends” as one makes small changes in the baseline of the averages. What you are doing is no different from what Hansen et. al. do/did when they drew a simple exponentially diverging fit to the temperature anomaly and predicted — oh so confidently — that the temperature right now would be some 0.2 to 0.4 C warmer than it is, extrapolating the trend from the 80s and 90s into the 2000s. Oops.

    Why commit the same, stupid, oops?

    rgb

  172. ROBERT BROWN MAKES MUCH SENSE IN HIS POSTINGS.

  173. ROBERT, do you see where I am coming from? I am saying once we are in a particular regime then relatively small short lived solar variablity, won’t necessarily correspond to temperature changes, because of the stronger negative feedbacks ,inherent in the climate system once it is in a particular regime.

    Only extreme changes in the items that control the climate (sun for example) can bring about enough of a positive feedback, to overcome those inherent neg. feedbacks to switch the climate into another state with a different range in temperature.
    So far nothing has come close to doing this up to this point, since we left the DALTON MINIMUM climate regime, and went to what we presently have. Only minor random variations have taken place since,causing random up and down temperature noise ,due to the random small oscillations in earth’s climatic system. Those(some examples) being convection rates in the tropics, to minor solar variations, to enso,to volcanic activity, to the arctic oscillation phase, pdo/amo etc etc. All strong enough to cause minor temp. changes ,but far to weak to bring earth’s climatic system to a threshold, which could bring it to another climate regime.

  174. Gail Combs says:

    Salvatore Del Prete says:
    June 21, 2012 at 4:43 pm

    this site is not letting me write in it ,the way I want to…..
    _________________________________
    I normally write in a word processor like Gedit or Libre Office Writer and then paste the comment. I make sure I have the html tags in place when I write and before I paste. Emax is used to check html tags in long posts if I can catch Hubby to do it for me. (I am computer challenged)

    Here is a guide to the HTML tags and lots of other stuff for WUWT: Ric Werme’s Guide to Watts Up With That

    Hope that helps.

  175. Robert Brown says:

    As Dr. Henrik Svensmark appears to have shown that there is a link between high cosmic radiation activity and cold weather periods on Earth, based on intervals when the Earth and the solar system were going through the spiral arms of the galaxy, where such radiation is high, I think it might be worthwhile to see if the Earth might have been transiting an unusual part of the galaxy during the Younger Dryas event.

    It wasn’t, as far as we can tell. The timescale for moving through galactic arms is many orders of magnitude larger than 1000 years.

    Look, I’m quite fond of Svensmark’s theory — where it is not true that he showed that there is a link between high GCR rates/solar state and climate (that was done long ago by other people) but he offered a plausible explanation for the link — GCRs create aerosols that nucleate clouds that modulate the albedo that cool the Earth, so that periods of low solar magnetic activity — correlated with high GCR rates — nonlinearly cool the earth compared to just the variation of TOA insolation that also corresponds to the low solar activity cycles. It is one of several competing explanations for the long term cycles of the planet into warm phases and ice ages, where we’ve been in an ice age for rougly 3 million years now, one expected to last several hundred million years! The current interglacial is a poorly understood bobble back to a transiently stable warm phase and is destined to end, probably end soon, unless we are lucky and the increased CO_2 in the atmosphere stabilizes us back in warm phase (a thing that sadly, I doubt will happen but one can hope on behalf of the several billion people that will die of starvation if it fails to and the cold transition is rapid).

    His mechanism is proven in the laboratory, but there is a fair amount of unresolved debate about its contribution in the field. Technically, there are problems with the size of the aerosol particles produced by GCRs and the size needed to nucleate water droplets that are large enough to spontaneously grow instead of shrink (IIRC at the 50 micron boundary). I still find their argument plausible, since even smaller nucleation sites should statistically shift the threshold for cloud formation when a conditions approach the critical point where they would (almost) do so spontaneously, but it is still an open question AFAIK.

    In the end, it still comes down to this — if the next 2-3 solar cycles are very low compared to the grand maximum (arguable as it is, in case Lief is listening:-) of the 20th century — at the very least a sort of local maximum at the end — then if Svensmark is correct the Earth’s albedo will increase (which it has arguably done) and temperatures will decrease by a moderately predictable amount. If the CO_2 plus high sensitivity people are right, sooner or later CO_2 will overwhelm even this effect and significant warming will resume, even if there is an albedo effect due to GCRs. If neither of them are correct and the bulk of the temperature variations is from a complex nonlinear multivariate process wherein the Earth shifts its own heating and cooing efficiency around quasi-“randomly”, then who knows what will happen? The NAO will shift phase and things will cool, or temperatures will just plain moderate and nobody will quite be able to explain why as the ocean rolls over, releasing heat (or not) laid down 1000 years ago (or not). Or the space aliens on the moon will relent and turn off their global warming heat beam that uses dark energy. Or the sun will indeed move into a different macroscopic state, but one we do not now anticipate or understand.

    I might live to see this evidence come home. I might not. But either way there will almost certainly be plenty of time to transition over from a carbon-burning world economy to a solar/nuclear/etc based economy without the collapse of civilization. It will indeed be expensive, and it will be cheaper the later we wait as the technologies required are not mature. It isn’t senseless to invest limited resources in improving the technology, in part because (in my very own opinion) in the long run solar is going to be by far the cheapest way to generate energy except for fission and, if it ever is worked out, fusion, and may pass even fission. It isn’t exactly stupid to burn carbon for electrical energy, but it isn’t — again in my own opinion — even a possible basis for a steady-state human civilization, which — in my own opinion — is a worthy goal to strive for, more important than reaching the moon or mars or discovering the Higgs particle or monopoles or decoding the human genome. Right now we are infinitely vulnerable as a species to a variety of “catastrophes”, and the economic catastrophe associated with “mined”, increasingly and artificially scarce energy resources is a constant threat to civilization and economic stability.

    So by all means, advance the solar hypothesis! I mostly believe it is true — there are indeed at least some very compelling correspondences in solar state and global temperature! But keep in mind that it is a hypothesis — or, in the case of Svensmark, a falsifiable theory — and is not yet proven or fully understood and that it is just one input in a complex system where CO_2 almost certainly is an important player.

    A good and proper skeptic should be skeptical about their own alternative favorite explanations and should acknowledge openly that they could be wrong and the CAGW people could be right. At the moment, the fair thing to say is that CAGW is far from proven (and that a lot of the research purporting to “prove” it is suspect) but it is far from disproven as well. The next few solar cycles should be very revealing.

    rgb

  176. agfosterjr says:

    That’s a hard act to follow, but:

    Gail Combs says:
    June 21, 2012 at 3:58 pm

    “That could also explain the wiping out of the mega fauna but not the sudden freezing with buttercups still in the mouth and undigested plant matter in the stomach found in some specimens.”
    =======================================================================
    Since I’ve gone to a wee bit of effort to put this canard to rest let me emphasize, before we read too much into these admittedly accurate reports, we should recognize two things: the process by which these animals died and were preserved is easily described non-catastrophically; there is concordantly no evidence that they died simultaneously. –AGF

  177. HenryP says:

    rgb says
    Why 37, 32, 22 and 12 years? Why not 37, 36, 35…?

    Henry says:
    Why would I? If I have 4 points of measurement I can do a regression, whether linear, nat. logarithmic or binominal, and calculate everything in between, with extreme accuracy, depending how near the r2 value is to 1. Really, my approach is very basic, first year stats, I suggest you do the course.
    37= average starting point 1974 of most stations
    32= 1980
    22= 1990
    12= 2000

    I would not use the results on the means as points to calculate because r2 is only 0.95. Rather use the nat. logarithmic or binominal regression on the maxima to calculate from whence we have started cooling down; r2= 0.997 and 0.995 respectively.
    I said: the black value in the tables is the measured average change in degrees K per annum from the average measured IN THAT PERIOD. That means those are the coordinates before the x in the(linear) trendlines for the period indicated.. How can A BIG SCIENTIST not understand that?

    You say my sample was not random and I challenge you on that. I have been sitting here with a globe trying to balance my sample according to latitude (longitude does not matter as earth rotates every 24 hours) and (on) sea – inland 70 – 30
    yet you claim that my sample is not even representative of the oceans???

    If you claim you trust UAH , do tell me the accuracy and precision and global representativity of those measurements?

  178. Dennis Cox says:

    Salvatore Del Prete says:

    June 21, 2012 at 4:43 pm this site is not letting me write in it ,the way I want to…..


    Since the Windows Live Spaces blogging platform was taken over to WordPress Microsoft has worked to make ‘Windows Live Writer’ 100% compatible with WordPress blogs.

    Live Writer is a true WYSIWYG writing environment. What You See Is What You Get. So you can compose a comment that you’re going to put post on WUWT, (or any other WordPress blog) complete with hyperlinks, and formatting.  And when you’ve got it looking the way you want it, simply click on the ‘Source’ button at the bottom left of the editor screen. And it’ll display your comment as html source code that’s perfectly compatible with the WUWT format.

    If you copy the contents of that ‘source’ page and paste it into the comment block of the blog you want to comment on it’ll get the html tags right for you every time.

    Windows Live Writer is free. And it can be downloaded from the Windows Live Essentials download page. And if you only want to install live writer without installing any of the other Live Essentials software you can do so.

  179. Steve P says:

    feet2thefire says:
    June 20, 2012 at 2:29 pm

    Let’s not forget that Darwin himself considered the extinction of the mammoths in northern Siberia to be an unsolvable puzzle.

    agfosterjr says:
    June 22, 2012 at 7:49 am

    That’s a hard act to follow, but:
    [...]
    …the process by which these animals died and were preserved is easily described non-catastrophically;

    I await your easy explanation with great relish.

  180. HenryP says:

    Steve P says
    I await your easy explanation with great relish.

    Henry says
    me too

  181. Robert Brown says:

    That means those are the coordinates before the x in the(linear) trendlines for the period indicated.. How can A BIG SCIENTIST not understand that?

    Change per annum is two numbers. One is \Delta T. This is divided by \Delta t. One is the temperature change. The other is the time interval over which it occurs. Temperature CHANGE is not the same thing temperature ANOMALY, although I suspect you are conflating the two — but since I can’t see your formulas, a big scientist like me has a hard time reading your mind. Imagine that.

    Here’s an example of the difference. Let’s make up a very short dataset:

    Y T T0 (T – T0)
    1 6 3 3
    2 6 3 3
    5 4 3 1
    6 4 3 1
    10 2 3 -1
    11 2 3 -1
    15 0 3 -3
    16 0 3 -3

    Here are two ways of turning it into data:

    Y (T – T0) /1 (T(Y+1) – T(Y))/1
    1 3 0
    5 1 0
    10 -1 0
    15 -3 0

    You’ll note that they give very different results. The first one does not plot the change in degrees per annum, it plots the anomaly for the year, which is not a derivative but a renormalized version of T(Y), the temperature. You’ve just changed the scale on which it is recorded. The second one actually computes the change in T from one year to the next, divided by the time over which the change occurs. This is a “change in temperature per year” whether relative to the average or not (the T0 cancels).

    I’m guessing that you are just plotting the anomaly itself as a function of Y, (T – T0) where even the dividing by one is ignored. Or perhaps you are dividing it by Y — again, you haven’t specified. Or maybe you are doing what your words actually describe, computing the final column which is the actual change in temperature per year. Being psychic, I actually know which one. But you certainly don’t say in your document.

    Let’s assume that you areally are just plotting (T – T0) as a function of the year it is computed in, the anomaly as a function of time, not the any kind of change PER anything (per being a word that literally implies a division that did not occur in your processing).

    As you note — and seem to brag about — you are fitting precisely four data points with three parameters. You don’t seem to want to reply why you chose a three parameter fit. Why not four? Fit a cubic and you’ll perfectly interpolate the four points, will you not? How can you do better than that?

    As for my needing to take a course. Obviously my words fell on deaf ears. I teach the course (and written my own linear and nonlinear regression routines), my friend, and you really do flunk. You aren’t even using first year stats correctly. Nor have you pointed out how you are doing the fit. What tool are you using? How does it compute R^2? Are you fitting all of the data in your columns or just the last four numbers? What is the Pearson’s \chi^2 for your fits and how did you compute it? Do you even know what that is, or what assumptions underlie its use?

    But you have, I confess, exhausted my patience. I have some real data to analyze, data worth real money. Your mistake is harmless enough because nobody is ever going to take your result seriously; I just thought you might like to learn what you are doing wrong and why your result is a very bad bet to extrapolate a few decades either way (and has almost zero predictive value). Its descriptive value as an approximation of these four data points — well, why not just plot them and let people see for themselves without a fit at all, rather than fit a meaningless curve through them? They can look and see that for the four years you select out of the 37 in the dataset, the mean goes down a bit, up a bit, then down a bit more, net descending. Since you don’t show us the other years, we cannot even judge what the natural variability of the anomaly is over the time interval in question — we have to accept whatever conclusion your four particular years lead us to. Nor can we see how well the curve you get predicts all the missing years! You might try plotting that out — you might learn something.

    But I doubt that you will.

    rgb

  182. Max_B says:

    Leif Svalgaard says:
    June 19, 2012 at 6:20 pm
    The 10Be we measure is determined both by production [about 2 ounces per year total over the globe] and by deposition.

    The fact that BE10 is also affected by deposition, does make one wonder about the accuracy of using these BE10 studies as a proxy for solar activity.

    However, the very idea of increased deposition modulating the BE10 signal also suggests – to me – that there must also have been ‘clouds’, without which one could not have had increased deposition?

  183. HenryP says:

    Henry@rgb
    on

    http://www.letterdash.com/henryp/global-cooling-is-here

    It looks like you still do not understand that every black figure in the table is the result of a separate (linear) regression; in a row it gives 4 regression results over 4 different time spans.

    … I give up ….

    why don’t you at least answer my question?
    If you claim you trust UAH , do tell me the accuracy and precision and global representativity of those measurements?

  184. Robert Brown says:

    It looks like you still do not understand that every black figure in the table is the result of a separate (linear) regression; in a row it gives 4 regression results over 4 different time spans.

    And could that be because — you don’t say that in your article? You think? Oh, wait, I admitted that I can read your mind already. Now if you could just tell me what that means in terms of just what you actually did the the actual data, those linear regressions leading to the black figures in your columns. Presumably each of the stations consists of a long row of dated numbers, T(t). What exactly does doing a linear regression fit mean? What interval did you fit? Are the numbers a coarse grained, centered average? What were the errors for the fit? What tools did you use? How could somebody reproduce your results? How does a regression fit lead you to max and min (which I would ordinarily interpret as just being precisely that, the maximum and minimum excursion from whatever).

    Nor have you addressed the points of my last post. Are you or are you not just plotting/fitting \Delta T = T - \bar{T} for four specific times? And what are you using for \bar{T} — is this per site?

    Don’t blame me, if you please, for not being able to see what you did from a table of numbers and an obviously incorrect paragraph of non-mathematical language involving “rates” that clearly don’t exist. Or are you inferring the rates from the linear fit? If so, please provide details for how the linear fit is done — how many years do you include on either side of the centroid at which you evaluate the slope, for example? Given the slope in this manner, what does \bar{T} have to do with anything (since it cancels!)?

    rgb

  185. Robert Brown says:

    (Aside: Tbar didn’t come through too well in the previous post — it is supposed to be “T average”, what I called T0 in a previous post).

  186. agfosterjr says:

    HenryP says:
    June 22, 2012 at 10:10 am
    Steve P says
    I await your easy explanation with great relish.
    Henry says
    me too
    ============================================================
    You guys aren’t paying much attention. How many times do I have to repeat myself–I’ve treated the problem three times in this thread already–why don’t you read the link? And are you Creationists now setting Darwin up as infallible or omniscient? We’ve learned a few things since the 19th century, you know. Another thing, do you expect all the animals to die of starvation? If they don’t, they will probably die with food in their stomachs. –AGF

  187. Dennis Cox says:

    agfosterjr says:

    [...]  “And are you Creationists now setting Darwin up as infallible or omniscient?” […]

    “Vastly ignorant minds”, “Catastrophists”, “Creationists”; heck, you sure are fond of labels. And even fonder of using them along with your childish, small-minded name calling in ad hominems in lieu of civilized, intelligent, communication .

    Do tell us; what insulting label would you like to be identified with?

  188. agfosterjr says:

    Dennis Cox says:
    June 22, 2012 at 2:47 pm
    ===================================
    Call me the guy who answers questions when asked. Still waiting for your answers. –AGF

  189. Robert Brown says:

    ROBERT, do you see where I am coming from? I am saying once we are in a particular regime then relatively small short lived solar variablity, won’t necessarily correspond to temperature changes, because of the stronger negative feedbacks ,inherent in the climate system once it is in a particular regime.

    Sure, and I mostly agree. The difficulty is that for you to be completely convincing, you need to show me a quantitative analysis, not just make statements, and that analysis has to use numbers that have some degree of corroboration — here’s where Lief is key, as there are several (supposed) flaws in the traditional solar activity curves caused (again, not my field, I’m reciting) from changes in the way certain people made the “official” sunspot count over the decades. There is also a less than perfect correlation between solar magnetic field, as inferred from radioactive proxies, and sunspot number, where the former will be correlated with GCR modulation a lot more than JUST the former.

    This has been done many times by many people, and there are some pretty good agreements, notably Maunder and Dalton on the minimum side. There is more controversy over the maxima — Ushokin (using IIRC Be proxies) concludes that the 20th century was an 8 or 9 thousand year grand maximum, explaining a lot of the anomalous heating if this general idea is correct where Lief argues that the renormalized sunspot counts no longer make the 20th century max’s “grand” — they’re high but not that high compared to the entire historical record. And Lief, if you are paying attention, I’m doing my best to paraphrase other people’s work, feel free to bop me upside the head if I go astray.

    So by all means, do a formal analysis over a REALLY long time period and see if you can come up with a picture that is really convincing. Sadly, there are fluctuations up and down that don’t seem to be associated well with solar fluctuations (and that are the same order of magnitude as what is observed overall). Maunder was the best, clearest example, and remains the most compelling, but the rest of the correspondences are “messier”…

    rgb

  190. Dennis Cox says:

    agfosterjr said:

    “Call me the guy who answers questions when asked. Still waiting for your answers. –AGF”

    Tom Elifritz saved me the trouble of responding to your silly strawman argument.

    But point of fact, you didn’t answer their question. This is not a pseudoscience site. I’ve backed up everything I’ve said with refereed literature; all published in well respected journals. And your only response to enough peer reviewed science to keep you busy reading and studying for years if you ever had any hope at all of really comprehending what it pertains to, was to come back with impertinent straw man arguments to side step the point. And to invalidate that science, with childish personal ad hominem insults saying that it was produced by “Vastly ignorant minds”.

    You failed to tell us about your own Curriculum Vitae, or how you attained such a lofty academic chair that you posses the authority to dismiss years of peer reviewed work on the stratigraphy of the Younger Dryas Boundary layer of by dozens of multiple PhD scientists out of hand. And never mind that most of them are tenured professors, and/or department heads at their respective and mostly prominent, institutions.

    Clearly the only response you’re capable of in the face of volumes of peer reviewed and compelling science that violates your own passionately held Uniformitarian/Gradualist confirmation bias, and that you are unable to even read much less comprehend, is to attack the scientists, and researchers who produced, and published, it with personal ad hominem attacks.

    So far, in your liberal use of straw man arguments, childish insults, and personal ad hominem attacks you’ve demonstrated the feeble logic and debate skills of a spoiled 10 year old.

    Your personal opinions, or someone else’s in an article on someone’s blog come under the heading of an appeal to inappropriate authority. You’re going to need to cite some real, and pertinent papers in refereed literature.

    Hopefully they’ll relate to the actual science and stratigraphic data from the YDB instead of more impertinent straw man arguments.

  191. agfosterjr says:

    DC, I have not appealed once to authority, but only to facts and logic. You live in a fairy tale world of your own creation, and when challenged with problems you go and hide in your shell. You seem never to have been exposed to critical thinking or clear thinking criticism; I have laid out a series of challenges and you have ignored them all. I’d just as well argue with a flat earther as with you.

    Dennis Cox says:
    June 20, 2012 at 11:22 am
    Some of the denials of the YD impact event are getting ludicrous.

    “There can no longer be any argument that the YDB layer is in fact a global impact layer. There is only one other global stratigraphic horizon with the same assemblage of impact markers; the Cretaceous/Tertiary Boundary layer.”

    A more absurd combination of ignorance and dogmatic posture we could not hope to find even from the CAGW crowd. The climate extinctionists are hopelessly deluded but they have you beat all to pieces. To repeat:
    1) The likelihood of a 100my event occurring in the last 20ky is 1/5000. That would be the chances of your theory being correct if it were not absurd on the face of it.
    2) No other extinction event has discriminated nearly exclusively by size. No theory explains this but overkill. Your feeble scientific background allows you to ignore entirely the simple glaring fact that Pleistocene extinctions include nothing but big game animals, but in this you have the dubious company of the extinction by climate quacks.
    3) The early history of the solar system, as documented on the moon’s more ancient surface, is sharply contrasted by the situation a few hundred million years after the moon’s formation, as documented by its younger surface.
    4) There is no evidence for simultaneous megafauna extinction; only for rapid extinction.
    5) You have failed to address at all the distribution and timing of megafauna extinction. Why did big wombats and ground sloths die, but island mammoths did not. Human hunting, of course.
    6) You fail to distinguish between independent arguments: a) evidence for periodic meteoric activity; b) evidence for Pleistocene extinction; c) evidence for DY rapid climate change. Your confounding of the three arguments is purely idiosyncratic on your part and on the part of whatever small and uniformed company you may have.

    I have presented a compelling argument for human overkill, enough to leave the climate extinction proponents wholly on the defensive. You have presented nothing but nonsense and shown yourself incapable of appreciating any rationale other than that of your own invention. We’re still waiting for a single argument by way of rebuttal, something other than dogmatic assertions of faith. –AGF

  192. Spector says:

    RE: Robert Brown: (June 22, 2012 at 7:27 am )

    “‘As Dr. Henrik Svensmark appears to have shown that there is a link between high cosmic radiation activity and cold weather periods on Earth, based on intervals when the Earth and the solar system were going through the spiral arms of the galaxy, where such radiation is high, I think it might be worthwhile to see if the Earth might have been transiting an unusual part of the galaxy during the Younger Dryas event.’

    “It wasn’t, as far as we can tell. The timescale for moving through galactic arms is many orders of magnitude larger than 1000 years.”

    The Svensmark theory effectively states that cooling is caused by increased cosmic radiation (or proton bombardment) from any source, galactic or otherwise. The short duration of this interval *may* be indicative of passage through a bounded region of intense fast protons. As galactic cosmic radiation is generated by multiple supernova events, passage through the expanded cloud of a single old, but comparatively recent event *might* create a intense effect of relatively short duration when compared with the time required to transit a spiral arm. That region might also include numerous small solid fragments making impact events more probable at that time.

    If one can say that it is known that the Earth was not transiting any such region during the Younger Dryas period, then the Svensmark theory does not apply.

    At about the 37 minute point of Svensmark’s video, “The Cloud Mystery,” it is stated that past cosmic radiation flux can be reconstructed from the state of iron meteorite fragments. Perhaps such data can be used to indicate whether or not the cosmic radiation flux was unusually high during the Younger Dryas period. I think that might better explain why this period lasted for a thousand years as opposed to the few decades that I would offhand expect from an impact event effect.

  193. HenryP says:

    Robert Brown says:
    And could that be because — you don’t say that in your article? You think? Oh, wait, I admitted that I can read your mind already.

    Henry says
    I don’t like your tone, as though I am the one who is stupid.

    http://www.letterdash.com/henryp/global-cooling-is-here

    I quote from my blog above:

    method:

    The (black) figures you are looking at in the tables below (allow some time to load up), represent the average change in degrees Celsius (or Kelvin) per annum, from the average temperatures measured during the period indicated. These are the slopes of the “trendlines” for the periods indicated, as calculated.
    end quote.

    Perhaps you don’t know what a slope is? A slope is the figure before the x in the linear equation that defines the rate of incline or decline of the plot – this equation is what we now call the trendlines. It is the rate of incline – or decline, when negative –
    and in my case the dimensions of the slope are of course degrees K per annum.

    anyway – – you don’t have to teach me anything and clearly you know it all- so let us leave it at that.

    I am just finding it very funny that you and Roy and everybody else “‘believe” in UAH and Hardcrut and GISS etc., but cannot tell me exactly how representative those measurements are of earth and what the precision and accuracy is, and when last the equipment on board of those satellites was calibrated.

    Until somebody does, I will rather believe the summaries of terrestial stations, where one can look at the differences, that you can easily pick up at each station,
    i.e. my own results,
    which show me that earth has started cooling down….
    thank you.
    It does not matter to me if nobody else believes me, because
    1) science is hard work- laziness and ignorance won’t get you very far
    2) science is not by consensus
    3) they will feel the cold that is coming soon enough.

    If you want to see an example of my analysis of a weather station I can mail you a relevant excel file.

    rgrds.
    Henry

  194. Dennis Cox says:

    agfosterjr said:

    “I have presented a compelling argument for human overkill, enough to leave the climate extinction proponents wholly on the defensive.”

    No, that’s not true at all. “wholly on the defensive?” Boy are you delusional! In fact you haven’t presented anything but your own subjective opinions, ad hominems, and straw man arguments. The fact that I refuse to dignify any of those straw man arguments with a response has nothing to do with being on the defensive. But rather, since you’re too ignorant to comprehend the nature, and content of the peer reviewed data that’s already been presented to you. There’s no point in trying to present more.

    And we have yet to see a link to peer reviewed literature that successfully makes the case for human overkill. In fact, since there is no physical way to prove such a hypothesis, there is nothing at all in the literature related to it that doesn’t consist of pure speculation, and mutual-inter-assumptive confabulation.

    “You have presented nothing but nonsense and shown yourself incapable of appreciating any rationale other than that of your own invention.”

    Nothing but nonsense? My own invention? In fact, I have presented more than a dozen recent peer reviewed references describing the chemistry, and stratigraphy of the Younger Dryas Boundary Layer at locations on three continents in exhaustive detail. I didn’t “invent” anything.

    The argument for Younger Dryas Impact Hypothesis is founded solely on the chemistry and stratigraphy of the Younger Dryas Boundary Layer. And the actual science of the YDB is a subject about which you are obviously completely clueless, and ignorant. What’s worse, you are in complete denial of the validity of that science without ever having read a single word of it.

    The fact that you lack the intelligence to read and comprehend the science those publications present and then expose your lack of intellectual integrity by proclaiming them to all be “nonsense” is your own problem. But work that is “nothing but nonsense” rarely survives peer review to get published in major journals like PNAS, or GSA.

    “We’re still waiting for a single argument by way of rebuttal, something other than dogmatic assertions of faith. –AGF”

    As I said, I have presented more than a dozen recent peer reviewed publications in major scientific journals. But since you lack the intelligence to read and comprehend what actual science I have already presented, proclaiming it to be “nonsense” without ever having read a single word of it,  and since you persist in trying to fabricate a smokescreen of straw man arguments to hide that ignorance behind without providing any valid references of your own, there’s really nothing to rebut. What’s the point if you’re too dimwitted to comprehend the volumes of data that’s already been stuffed down your throat?

    You haven’t provided a single reference to real peer reviewed science to support your own personal opinions, and invalidations of the refereed literature that’s already been provided. So do tell us about “dogmatic assertions of faith.”

    You obviously lack the intellectual integrity to acknowledge, and intelligence to comprehend peer reviewed scientific references when provided. And since you are only capable of responding to them with ad hominem, any further debate with you is a completely demeaning waste of my time.

  195. That is why I think solar flux is a better indicator for solar activity,since that number is much more consistent ,then the sunspot number. Everyone seems to count sunspots in a different manner.

    MAUNDER MINIMUM SUNSPOTS- My guess is if we were using the equipment of today back then ,that the sunspot numbers during that period of time, would have been higher making this current period even more of a fall off in activity.

    Up to this point the solar activity prior to Oct.2005 was high, the solar activity since Oct.2005 ,has been low, with the most extreme part of this low cycle yet to come.

    The evidence if one looks at all the data to me is quite convining, that if the solar activity goes into a deep minimum for a long enough period of time ,that the temperatures will respond .

    What is so great about this present situation we now have, is the possibility for the sun to have a GRAND MINIMUM is high, and I think if that happens we will find out just how much influence the sun has on earth’s climatic system.

    The LAYMAN SUNSPOT SITE, is a great site to visit, and if one goes through the daily summaries,there are sometimes research articles attached to the end of the summary ,that support the solar/climate linkage.

  196. Again the climate system has many feedbacks and much of the time the negative feedbacks will rule, and if the climate is in a particular regime then variations in all the items that control the climate will just result in random temperature flucuations up or down.

    The temperatures when in this situation, will correspond to the item which is able to exert the most force on the climate compared to another item.

    For instance if their is a SLIGHT drop off in solar activity ,and the PDO enters a warm phase at the same time ,temperatures are going to go up.

    If a strong EL NINO were to develope temperatures would go up ,even if solar activity was down a little.

    Until positive feedbacks from one of the sources that controls the climate is strong enough to over come the inherent negative feedbacks in the climate system ,it is going to be very hard to see how x item, effects the climate, in a convincing way.

    This is why,it is so hard to come up or show a direct cause and effect. There are always competing feedbacks going on at the same time.

  197. agfosterjr says:

    Dennis Cox says:
    June 23, 2012 at 1:43 am

    You continue to hide behind your facade of authority, and to ignore every challenge. Please tell us why the YD extinctions were purely size specific. Or if you prefer, please refer us to any literature that addresses this critical problem. This is a primary objection, and neither you nor anyone else addresses it adequately. Of course the principle problem with your claim is that no YD catastrophe or extinction in any way comparable to the K/T event ever took place–there is no evidence for it. There is simply no evidence for any YD extinction except for what is easily explained by overkill, which clearly preferred big game animals. That’s where you and your literature should start, once you pull your head out. –AGF

  198. Robert Brown says:

    At about the 37 minute point of Svensmark’s video, “The Cloud Mystery,” it is stated that past cosmic radiation flux can be reconstructed from the state of iron meteorite fragments. Perhaps such data can be used to indicate whether or not the cosmic radiation flux was unusually high during the Younger Dryas period. I think that might better explain why this period lasted for a thousand years as opposed to the few decades that I would offhand expect from an impact event effect.

    I don’t think the method has a resolution of Ky. It’s used on a My basis to argue for the galactic arms passages. I do not know the answer WRT radioactive proxies from the YD, but Lief probably does, and then there is the literature…

    Agreed, though, that any of a number of extrinsic solar/galactic events could have been the proximate cause. They go into our common sense judgment that other explanations without them are right, decreasing their plausibility somewhat. But the simpler all things being equal explanations are still far more likely, barring specific supporting evidence of the sort you refer to.

    rgb

  199. Still waiting for your answers.

    Armchair scientists wait for answers. Real scientists look for answers.

  200. Robert Brown says:

    The (black) figures you are looking at in the tables below (allow some time to load up), represent the average change in degrees Celsius (or Kelvin) per annum, from the average temperatures measured during the period indicated. These are the slopes of the “trendlines” for the periods indicated, as calculated.

    Sigh. And neither this, nor you now, actually tell us how you calculated these slopes, does it? Which is why when you (above) told me that you did it with “linear regression on the individual stations” or the like, it was news to me. Is there somewhere in this paragraph where you mention linear regression? Is there someplace that you explain how you are using linear regression to obtain the slopes, especially the slopes as a function of time (which linear regression per se will not give you, because it returns a straight line fit of the data and cannot therefore return the acceleration). I’m sure that you do something to work around this, but what? You don’t say. Still.

    Let me put it yet another way. Do you think that your description of method suffices to enable a second person to duplicate your results?

    I hope that the answer is obviously not, because it doesn’t. Nor does it permit a second person to assess your results and decide whether or not they agree with them even so far as to whether you have produced a reasonable fit of a reasonable trend over the specific interval.

    But clearly we are at an impasse here. I’ve tried my best to help you at least clearly communicate your results (while at the same time pointing out vast areas where lacking a description of your methods that a third party could duplicate precisely to reproduce your results they are subject to doubt, and what some of the limitations are on the result even in the best of circumstances where what you do is precisely correct). If I were refereeing your paper in an actual journal, I would absolutely refuse to recommend publication until you fix up your methods section to something like scientific standards, which should be enough to permit verification by a third party without having to read your mind or guess.

    You seem to stubbornly want to insist that you’ve described it sufficiently, in spite of the specific omissions I’ve pointed out and that have come out in our discussion, such as your use of linear regression in some unspecified way to obtain the slopes as a function of time, the actual tools you are using to perform the analysis, how R^2 is being computed, what \chi^2 might be for the actual final fit (requires error estimates, not given, for your primary fit along with a description of the fit software or method), and why you stopped at quadratic when cubic would give you no error at all in the fit (but a very different extrapolation outside of the region — why (not) constant, why (not) linear, why (not) quadratic, why (not) cubic? Of course a higher order polynomial will give you a better fit, and one with the same number of degrees of freedom as the fit data will give you a perfect fit, so what is your justification for terminating at some degree? It can’t just be “gives the best fit” or “because it shows what I want to believe, which is that temperatures are downturned now after rising in the past”. You have to explain why you expect a quadratic behavior now, when there has never been one in the past except as an accident of Taylor Series when examining a bobble of the data in the vicinity of a peak or minimum embedded in a completely different longer time scale trend (that itself may be only a bobble in a still longer time trend, see the Koutsoyannis paper).

    These are all, I think, reasonable objections, but you just want to point at your result and crow instead of expand on your methods so I (or anybody else) can understand them and replicate them.

    I would therefore respectfully suggest that we terminate the discussion. You are welcome to think that I’m just stupid because I can’t just see what your are doing to get the slopes from the infilled data you’ve “randomly” selected without dice, or why you think quadratics are going to be meaningful in a four point aggregated fit. Or whatever it is that you actually do to obtain your fit quadratics, as silly old me just can’t quite make it out from your two paragraph, algebra free description.

    Good luck getting people to your blog and convincing them that you have proof that temperatures are reliably descending from a 1994 (or whenever) peak, and that your quadratic will of course extrapolate indefinitely into the future and hence has real predictive value. I’m about to close the window I’ve had open on your paper for several days now trying to make sense of it, but I’m sure you can find others who will instantly infer all of the missing methodology and shower you with the accolades you seem to crave.

    rgb

  201. HenryP says:

    Henry@rgb(the duke)

    Ok, Richard, just for you I will exchange the word ‘trendlines” for “the least square fit”
    in that line seeing you obviously have absolutely no idea how to do (linear) regression in excel, nevermind how to use any regression to get some answers to the questions I had…..namely if man contributed anything towards “global warming”

    I told you I am not looking into the future. The cold is already here (no extrapolation into the future necessary). I was as astonished by the results as you must be. Clearly, it is the sun, losing strength, as shown by the descent of the maxima. I did offer to show you how I got my values but you ignored that too.

    Where do get the idea I am craving for accolades?
    Figures (results of measurements) are a bit of hobby to me, I am here to give a service and to keep my brains a bit active.Your loss to you if you or anybody else do not want to take heed.

    I, and I am sure everybody else, notice again that you have no answers to the questions I posed to you, which makes your criticism of my work look, ehhh, …..a bit ….stupid?

  202. Spector says:

    RE: Robert Brown: June 23, 2012 at 7:52 am

    “But the simpler all things being equal explanations are still far more likely, barring specific supporting evidence of the sort you refer to.”

    That’s right. All I am suggesting is that it might be worth a check to see if the solar system might have been transiting an unusual part of the galaxy at that time.

    If a dead body is found with multiple bullet wounds, we usually assume that he had been shot–but if we also find that a nearby munitions factory had just exploded, there might be a different explanation.

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