We all know how much NSIDC’s Dr. Mark Serreze has been touting the idea of the “Arctic death spiral“, and we’ve had predictions of ice free summers in 2008, 2013, 2015, 2020, 2030, 2040, 2050, 2060, 2070, and 2100 to name a few. Other forecasts don’t give specific dates but say things like within 5 years, 10 years, 20 years, 30 years, 100 years, decades, and sooner than expected. Such “all over the road forecast certainty” doesn’t really build any confidence that any of these climate soothsayers have any idea when or even if the Arctic will be “ice free” in the summer in the next 100 years.
Now, inconveniently, we have this new paper via ScienceDirect New insights on Arctic Quaternary climate variability from palaeo-records and numerical modelling which says that their studies show that the early Holocene might very well have had ice free summers. This is interesting, because as this generally well accepted graph shows, temperature was higher then. But there’s more.
From the description for this graphic: The main figure shows eight records of local temperature variability on multi-centennial scales throughout the course of the Holocene, and an average of these (thick dark line). (to 10000 BC-2000CE (from 0 — 12000 BP)) The records are plotted with respect to the mid 20th century average temperature, and the global average temperature in 2004 is indicated. An inset plot compares the most recent two millennia of the average to other recent reconstructions. At the far right of this plot it is possible to observe the emergence of climate from the last glacial period of the current ice age. During the Holocene itself, there is general scientific agreement that temperatures on the average have been quite stable compared to fluctuations during the preceding glacial period. The above average curve supports this belief. However, there is a slightly warmer period in the middle which might be identified with the proposed Holocene climatic optimum. The magnitude and nature of this warm event is disputed, and it may have been largely limited to high northern latitudes.
But, the other rub of the early Holocene is CO2 in the atmosphere. We know from ice core records that CO2 concentration has varied with ice ages. Coming out of the last ice age into the Holocene, we know that atmospheric CO2 concentrations rose as CO2 came out of the oceans as they warmed. This graph from the American Association for the Advancement of Science (AAAS) shows that the early Holocene (~10,000 years before present), had a rise coming out of the ice age and then had CO2 concentrations stabilize lower than that of today, about 260-270 ppm:
Figure 1. Top: One sigma-calibrated age ranges for the 14C control points 1, 2 and 6 as an indicator of the possible age range of the CO2 record reconstructed from stomatal frequency. The labels are the same as in Wagner et al. (1). Center and Bottom: Atmospheric CO2 concentration reconstructed from stomatal index (
) (1) and direct measurements of CO2 concentration of air enclosed in bubbles in the ice cores from Taylor Dome (
) (3, 4) and Vostok (
) (7, 8).
This new paper in the journal Quaternary Science Reviews throws a formidable monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss. Because if we had ice free summers ten thousand years ago at ~ 260 ppm CO2, and we had warmer temperatures than today, we can’t then conclude that an additional 100 ppm of CO2 since then would be the cause of an ice free summer in the Arctic today. And ice free summer at lower CO2 and higher temperature is an incongruity with today’s theory of the “Arctic Death Spiral”.
Here’s the paper abstract:
New insights on Arctic Quaternary climate variability from palaeo-records and numerical modelling
Abstract
Terrestrial and marine geological archives in the Arctic contain information on environmental change through Quaternary interglacial–glacial cycles. The Arctic Palaeoclimate and its Extremes (APEX) scientific network aims to better understand the magnitude and frequency of past Arctic climate variability, with focus on the “extreme” versus the “normal” conditions of the climate system. One important motivation for studying the amplitude of past natural environmental changes in the Arctic is to better understand the role of this region in a global perspective and provide base-line conditions against which to explore potential future changes in Arctic climate under scenarios of global warming. In this review we identify several areas that are distinct to the present programme and highlight some recent advances presented in this special issue concerning Arctic palaeo-records and natural variability, including spatial and temporal variability of the Greenland Ice Sheet, Arctic Ocean sediment stratigraphy, past ice shelves and marginal marine ice sheets, and the Cenozoic history of Arctic Ocean sea ice in general and Holocene oscillations in sea ice concentrations in particular. The combined sea ice data suggest that the seasonal Arctic sea ice cover was strongly reduced during most of the early Holocene and there appear to have been periods of ice free summers in the central Arctic Ocean. This has important consequences for our understanding of the recent trend of declining sea ice, and calls for further research on causal links between Arctic climate and sea ice.
~~~~~~~~~~~~~~~~~~~~~~~~~~
Fig. 1. Map showing the locations of some of the studies included in the papers presented in this special issue. Numbers refer to Table 1, which contains the references to the respective study. Some of the papers on the Arctic Ocean involve sediment cores from a large spatial area; these are only plotted with boxes enclosing the areas of the studied cores. Furthermore, Cronin et al. (2010) analyzed sediment cores from virtually the entire central Arctic Ocean and, therefore, there is no number representing that study on the map. The maximum extensions of the Eurasian Ice Sheet during the late Quaternary compiled by the QUEEN project (Svendsen et al., 2004) are shown. LS: Late Saalian (>140 ka), EW: Early Weichselian (100–80 ka), MW: Middle Weichselian (60–50 ka), LGM: Late Weichselian (25–15 ka). The speculative extent of an MIS 6 ice shelf inferred by Jakobsson et al. (2010) is shown by the hatched area enclosed by a gray stippled line. The approximate spatial minimum cover of sea ice during 2007 is shown with a white shaded area enclosed by a black stippled line as a comparison to the median extension for the period 1979–2005 shown by a blue stippled line (Data is from National Snow and Ice Data Center). MJR: Morris Jesup Rise; YP: Yermak Plateau. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
================================
h/t to WUWT reader “josh”
Addendum: Some follow up graphic from comments, in my response to Richard Telford:
Here’s an interesting plot of solar insolation at 65 degrees north over time. To give readers an idea of this line, here is a map:
(Map from WikiMedia) Fairbanks, AK is at 64.5° N
The plot below shows how insolation varied with the Milankovitch cycles at 65° N. I’ve added the deltas comparing 10KYA to present.
The “Fermi Paradox” blogger who originally made the graph I annotated wrote: The graph shows the insolation in W/m^2 at 65 degrees norther latitude from 20ky before present to 10 ky in the future, calculated with the program insola from J. Laskar et al. The four plots are for the two months after the summer solstice and the two months before. It can be seen that the change in insolation over time is quite significant. Note though that this only applies at high latitudes – the global mean barely changes at all.
Note the magnitude of the change in insolation from 10K years ago to present, from 15 to 40 Watts/m2
Now look at this image from NOAA’ s Environmental Research Laboratory (ESRL):
CO2 accounts for 1.4 Watts/m2 of forcing in the last 150 years, so compared to the forcings of the Milankovitch cycles (at least at 65N) it is an order of magnitude lower. My point is that given the small impact of CO2 in forcings, it is not likely to be the driver of Arctic ice melt in the present, just like it wasn’t much of a significant factor 10K years ago.
Why couldn’t the phase changes of water lead to different levels of climate stability, overwhelming other constituents in the climate system? If you look at the historical evidence, it seems that in the current continental alignment patterns, when ice is the dominant phase for water, the temperatures are colder (duh, I know) and more variable. When liquid is the dominant phase, temperatures are warmer and less variable.
Without speaking to the quality of samples or appropriateness of proxy, the proxies used in the above graph seem to indicate this as you move out of the ice age. All the gibberish about thirty year trends is nonsense when you look at this information. For instance, whatever the dark red proxy is shows a long term cooling trend. So does the cyan colored proxy. Could we really be on a long term cooling trend since the end of the last ice age? No, but interesting that there are two separate proxies that show this.
Still, the amount of ice in the hydrological cycle seems pretty important to the climate. This is one reason why I think Hansen’s attempts at deriving climate sensitivity from the LGM are useless in a largely ice free Holocene.
Yet another thing to consider is the log effect of LW absorption CO2 has. Look at the fast rise in the black line, which released large amounts of CO2 from the ocean. On that point, I haven’t heard much quibble from proponents. Why wouldn’t water vapor have amplified that more so than it would now? Despite the large releases of CO2, the climate largely stabilized when the transition from ice-dominant to vapor-dominant completed. Could it be that water vapor is a stabilizing force in our atmosphere and that as we move away from the sun, evaporation will lessen and renew the importance of CO2 in the atmosphere? For a little while at least…
Oh dear, oh me, oh my…
This paper is going to be tarred and feathered over at the Not-So-Real Climate website.
Can’t wait to read their pseudoscience rebuttals and he-man chest poundings in 3…2…1…
Additional thought to my last paragraph:
When that black line takes off to the sky, it reaches a point where water vapor begins to coalesce into clouds. Is there any proof of the frequency of clouds in the paleo-climactic records? Or that they even existed? That may sound silly, but I think that it is an important point to consider.
I must protest against the phrase “climate solons.” Solon means a legislator, and I certainly don’t want Hansen et al. making my laws.
REPLY: I meant to say “soothsayers” but instead wrote “solons” for some reason. Fixed, thanks – A
But doesn’t this mean someone could have made millions of dollars shipping goods through the North West Passage at the time of the ice free conditions? If only I could have been alive at the time. I could have been a billionaire then, by cornering the market in NWP shipping.
I just want to make sure I understand the point of the post.
In the early Holocene temperatures were higher than they are now and there is evidence to suggest that there may have been summers where the central Artic Ocean was completely ice free.
Yet CO2 was lower then that it is now
So therefore we cannot conclude that the dramatic increase in CO2 concentrations in the atmosphere in the past 150 years that is a direct result of human activity is one of the principal drivers in the current warming trend?
Did I get that right?
Cause its my understanding that there can be factors that drive global temperatures other than CO2 concentration and perhaps those other factors were in play 10000 years ago.
I don’t know of any Climate Scientist that claims that they can tell you what the global average surfact temperature might be based purely on knowing the concentration of CO2 in the atmosphere.
The science behind Global Warming/Climate Change, as I understand it, concludes that when you look at all the factors that might drive global temperatures, the factor that is driving temperature right now is CO2. I don’t think that they conclude that it was always the major forcing factor.
So how does this research fundamentally challenge the basic conclusions of Climate Change/Global Warming?
REPLY: Why should we bother to try explaining it, you will simply say These People are Nuts
Additionally (or P.P.S, lol) when considering the phase changes of water, consider the evaporation of water. If ice melts, we experience runoff, evaporation, pooling, geological changes in mineral deposits, and a whole host of things. runoff, evaporation, and pooling are the important ones. As the ice melts, some water evaporates, some runs to the sea, and some will pool in various areas for various reasons. Water that has pooled will continue evaporating. Water that has runoff cannot. Water that has evaporated cannot. As the Earth loses water to runoff and evaporation, the atmosphere will become drier and lose water vapor. eventually, the clock runs out, and the atmosphere loses the necessary amount for Earth to become an extremely cold place to live, halting most evaporation processes. On our way away from the Sun wrt Milankovitch. Just an additional thought. I think that the hydrological cycle is much more important than climate scientists have considered. The key piece being evaporation, because evaporation is work performed by he energy in Earth’s climate.
“The science behind Global Warming/Climate Change,….”
Whoa! science, what science Uncle Walt?
Manmade global warming is Swiss Cheese Science – Full of holes that we’re supposed to not notice and not comment on. And if we do, we’re the unhinged ones!
That sounds like a winning strategy. How’s that working these days?
It seems more like a political crusade with the added side benefit of claiming “I saved the planet!”
If you want to do something useful Uncle Walt, you can help promote these two efforts.
http://www.lutw.org/
http://www.samaritanspurse.ca/ourwork/water/default.aspx
One thing we need to keep in mind is our perspective of arctic sea ice. The LIA lasted, give or take from roughly 1300 to 1850. This was *the coldest* period of the Holocene since the Younger Dryas.
How many accurate descriptions of Arctic ice conditions do we have prior to the 14th century? Our good documentation of Arctic ice conditions begins in the middle of the LIA. We are probably *still* recovering from that event. That event lasted long enough that it would be rational for many people to consider that condition to be “normal” If a certain place had sea ice for 300 years and now in the past 100 has none, and there is no documentation of what the place was like >300 ya then it would be logical to think that some would believe that icy condition was “normal” and today’s conditions are “abnormal” when in fact, we could well be experiencing conditions that are closer to “normal” for the Holocene than they were 200 years ago.
The chart looks pretty much like any of the interglacials from the Vostok ice cores – a very rapid rise out of the ice age followed by a slow descent into the next one. We really need a credible explanation as to why this happens. CO2 was never going to explain it. Two separate positive feedback mechanisms are needed to explain the slow decent into, and steep rise out of, an ice age. Any suggestions from anyone?
What I’m considering at the moment is there may be a limit to the maximum possible height of the polar ice sheets. Once they reach a certain height (10,000ft+) then precipitation of new ice stops stops as it’s too high up there to snow. This then stops the removal of water vapor from the polar atmosphere by snowfall. There is always going to be melting at the edges because of the lower latitude and GHG warming from the water vapor and whatever CO2 is in the atmosphere.
Once the precipitation stops then all that remains is the melting from the edges. Evaporation from the melt water maintains the higher humidity and rainfall helps to melt the ice further up. Removal of the edges causes the glaciers to flow more strongly which transports the bulk of the ice to lower latitudes for melting. There you have a possible positive feedback mechanism.
Ice is the ‘great big switch’. It causes a big jump in albedo and a big drop in humidity. The reverse it true when it melts. The binary nature of ice leads to two states – glacial and interglacial. Unfortunately the melted ice from the ice sheets has left no record. If we know (or could model) how they built up and melted, then we might see the two positive feedback mechanisms at work.
Whatever the cause, we are in a bog standard interglacial and the descent to the next one is well under way. CO2 is the minor player. Water vapor is always the main GHG. The Greenland GISP2 temperature chart shows lower highs and lower lows since the end of the Minoan warming so the descent started about 3200 years ago.
You have taken the wiki page for the first figure, and the data come from
The following data sources were used in constructing the main plot:
1. (dark blue) Sediment core ODP 658, interpreted sea surface temperature, Eastern Tropical Atlantic: M. Zhao, N.A.S. Beveridge, N.J. Shackleton, M. Sarnthein, and G. Eglinton (1995). , Paleoceanography, 10(3): 661-675. doi:10.1029/94PA03354
2. (blue) Vostok ice core, interpreted paleotemperature, Central Antarctica: Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J., Delaygue G., Delmotte M., Kotlyakov V.M., Legrand M., Lipenkov V., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M. (1999). , Nature, 399: 429-436. doi:10.1038/20859
3. (light blue) GISP2 ice core, interpreted paleotemperature, Greenland: Alley, R.B. (2000). , Quaternary Science Reviews, 19: 213-226. doi:10.1016/S0277-3791(99)00062-1
4. (green) Kilimanjaro ice core, δ18O, Eastern Central Africa: Thompson, L.G., E. Mosley-Thompson, M.E. Davis, K.A. Henderson, H.H. Brecher, V.S. Zagorodnov, T.A. Mashiotta, P.-N. Lin, V.N. Mikhalenko, D.R. Hardy, and J. Beer (2002). , Science, 298(5593): 589-593. doi:10.1126/science.1073198
5. (yellow) Sediment core PL07-39PC, interpreted sea surface temperature, North Atlantic: Lea, D.W., D.K. Pak, L.C. Peterson, and K.A. Hughen (2003). , Science, 301(5638): 1361-1364. doi:10.1126/science.1088470
6. (orange) Pollen distributions, interpreted temperature, Europe: B.A.S. Davis, S. Brewer, A.C. Stevenson, J. Guiot (2003). , Quaternary Science Reviews, 22: 1701-1716. doi:10.1016/S0277-3791(03)00173-2
7. (red) EPICA ice core, δDeuterium, Central Antarctica: EPICA community members (2004). , Nature, 429(6992): 623-628. doi:10.1038/nature02599
8. (dark red) Composite sediment cores, interpreted sea surface temperature, Western Tropical Pacific: L.D. Stott, K.G. Cannariato, R. Thunell, G.H. Haug, A. Koutavas, and S. Lund (2004). , Nature, 431: 56-59. doi:10.1038/nature02903
I have an objection with averaging proxy temperatures coming from different proxies and different locations.
As we see in the plot , there are much larger variations than the average shows. If each curve, because of the methodology is out of phase or its calibration with temperature is not stable over the years ( as with tree rings, other factors at other times might influence the proxy analogue) averaging them is like mixing cold soup with hot soup.
One should look at the individual curves and how they compare with the present .
I do not doubt that at warmer periods in the Holocene the Arctic ocean may have been navigable: but for all practical purposes not for the last few hundred years.
What I do find fascinating is the folklore from over a thousand years ago that you could indeed sail across the roof of the world. And that that folklore exists in two separate cultures, the Norse and thus northern European culture BUT also in Chinese culture too.
The legend persists and drove the British to explore the possibility for two hundred years: without success
Legend is just that, we have nothing to show that it was so, but we do know that these two cultures were the first to develop ships, although of very different designs, which were capable of reaching and indeed crossing the Arctic ocean. Just over a thousand years ago.
And that they did explore it: although we have no written records of the result.
Folklore is no reliable guide to the past but often seems to contain more than grain of truth and when two separate cultures which never really met until several hundred years later both tell tales of the same thing that supposedly happened a thousand years ago then perhaps it was really so.
Whatever the Arctic ocean is icebound today: but it might possibly become open to navigation once again nut not in my lifetime I imagine.
Kindest Regards
Good to see another post about climate. Are there any useful cross references to sea-level, temperature and climatic conditions at this time? I assume that coming out of an ice age had a cause that was independent of C02, although as you have pointed out, the co2 feedback may well have contributed. The thought had come to my mind that there is a message here about climate sensitivity. If the change in orbit/inclination or whatever that started the change is known. The C02 change is known, so the post-ocean C02 release temperature should give a good indication of climate sensitivity. I think we can forget about arctic ice let’s move on to the next challenge.
Found this-
The Piri Reis map shows the western coast of Africa, the eastern coast of South America, and the northern coast of Antarctica. The northern coastline of Antarctica is perfectly detailed. The most puzzling however is not so much how Piri Reis managed to draw such an accurate map of the Antarctic region 300 years before it was discovered, but that the map shows the coastline under the ice. Geological evidence confirms that the latest date Queen Maud Land could have been charted in an ice-free state is 4000 BC.”
http://www.world-mysteries.com/sar_1.htm
If we had thousands of feet of ice over Chicago during the last ice age, is it reasonable to assume the Arctic Ocean was then solid to the bottom (salt water notwithstanding, not that I know)?
The Holocene thaw would then take a while to turn it back into an ocean, thousands of years for it to refill, reconnect with the Pacific, and get settled into a stable body of water with stable circulation patterns. We could easily expect an overshoot in the process that would leave it ice free for a while.
anna v says: October 30, 2010 at 11:59 pm
You have taken the wiki page for the first figure, and the data come from
The following data sources were used in constructing the main plot: . . .
You missed the folks at the bottom, emph. mine –
Additional data used in inset plot and for matching temperature scale to modern values. Colors match those used in Image:2000 Year Temperature Comparison.png.
1. (orange 200-1995): P.D. Jones and M.E. Mann (2004). , Reviews of Geophysics, 42: RG2002. doi:10.1029/2003RG000143
2. (red-orange 1500-1980): S. Huang (2004). , Geophys. Res Lett., 31: L13205. doi:10.1029/2004GL019781
3. (red 1-1979): A. Moberg, D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén (2005). , Nature, 443: 613-617. doi:10.1038/nature03265
4. (thin black line 1856-2004): Instrumental global annual data set TaveGL2v [2]: P.D. Jones and A. Moberg (2003). , Journal of Climate, 16: 206-223.
bublhead says:
October 30, 2010 at 10:50 pm
The science behind Global Warming/Climate Change, as I understand it, concludes that when you look at all the factors that might drive global temperatures, the factor that is driving temperature right now is CO2. I don’t think that they conclude that it was always the major forcing factor.
There are many instances of “scientists” trying to attribute CO2 to nearly every climate or extinction event throughout history. Here is just one example.
http://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum
If it is not cited as the cause it nearly always attributed as the dominant driver of climate shifts. CO2 is the manic obsession of todays university inspired Marxist science.
Wild swings of CO2 have always been shown to be the result of and not the cause of climate changes and extinctions.
As the article says CO2 has been lower through the Holocene epoch even when temperatures have been much warmer than now.
Why?
I am not quite sure how you can write a post about the early Holocene warm period and not mention that orbital (Milankovitch) forcing gave higher summer insolation in the early Holocene. It suggests either that you don’t really understand the issues, or you don’t want your readers to. The conclusions of this paper are entirely reasonable – you will be hard pressed to find any palaeoclimatologists who are surprised that sea ice extent was lower in the early Holocene. When it gets warmer, ice melts. Ice doesn’t particularly care whether it is warm because of high insolation or high CO2 levels.
REPLY: Oh Mr. Telford, anything for denigration as usual. Good to see your MO has not changed. Here’s an interesting plot of solar insolation at 65 degrees north over time. To give readers an idea of this line, here is a map:
(Map from WikiMedia) Fairbanks, AK is at 64.5° N
The plot below shows how insolation varied with the Milankovitch cycles at 65° N. I’ve added the deltas comparing 10KYA to present.
The “Fermi Paradox” blogger who originally made the graph I annotated wrote: The graph shows the insolation in W/m^2 at 65 degrees norther latitude from 20ky before present to 10 ky in the future, calculated with the program insola from J. Laskar et al. The four plots are for the two months after the summer solstice and the two months before. It can be seen that the change in insolation over time is quite significant. Note though that this only applies at high latitudes – the global mean barely changes at all.
Note the magnitude of the change in insolation from 10K years ago to present, from 15 to 40 Watts/m2
Now look at this image from NOAA’ s Environmental Research Laboratory (ESRL):
CO2 accounts for 1.4 Watts/m2 of forcing in the last 150 years, so compared to the forcings of the Milankovitch cycles (at least at 65N) it is an order of magnitude lower. My point is that given the small impact of CO2 in forcings, it is not likely to be the driver of Arctic ice melt in the present, just like it wasn’t much of a significant factor 10K years ago. -Anthony Watts
I can only read the abstract, but is this really all that surprising? Variations in the Earth’s orbit will change the amount of sunlight reaching the Arctic in the summer, and we had the last peak around 9000 years ago.
http://www.eoearth.org/article/Milankovitch_cycles
More heat causes melting of the Arctic, and whether this heat comes from Milankovitch cycles or CO2 doesn’t matter, thus the claims that this should somehow contradict that current melting of the Arctic is due to more CO2 is misplaced.
What will such a melt period do to the ice deposition on Greenland?
They confidently count ice-rings back into the past, to achieve a geological chronology, but during such a warm period they may be missing a few thousand ice-rings (years).
.
I think my post above is agreeing with what Dave F is saying bit I would add albedo to water vapor as another positive feedback. Both act as positive feedback in the descent into, and the exit from, an ice.
John Kehr has an interesting posting on “Climate Sensitivity of the Northern Hemisphere” which indicates that the Milankovitch cycle can increase summer insolation by 11% (50 W/m2) in the Nothern Hemisphere… which is consistent with the Holocene peaking when the Artic has an ice free summer.
Unfortunately we are now on the downward slope… and as John Kehr states in his article: Although change in forcing is slow, it is relentless
http://theinconvenientskeptic.com/2010/10/climate-sensitivity-of-the-northern-hemisphere/
The current interglacial was “triggered” by a change in the orbital parameters of the Earth’s orbit that caused the NH to have a period where the amount of energy it received during the summer increased 11%, or about 50 W/m2. The temperature of the NH changed about 12-14 °C with that change in energy.
…..
While the temperature change is larger for the NH alone, so is the change in solar energy (forcing). Although change in forcing is slow, it is relentless. Every summer, over the course of 10,000 years, gets slightly more energy than the summer before. This results in more and more melting of the ice sheets. Summers 10,000 years ago in the NH received 10% more solar energy than the they do now.
PS
The article is also a really great demonstration of why it is just crazy to construct and monitor Global Averages (even if they were possible)… the North and South have different climate sensitivities… and the Global Average can hide a multitude of sins.
The really vital message here is that the arctic can be ice free without triggering any of the conjectured `tipping points’ leading to runaway warming. It suggests that an ice free arctic is something that has happened before and will likely happen again. An ice free arctic is not a disaster.
I also think this is the best Long Term forecast I have seen:
http://theinconvenientskeptic.com/wp-content/uploads/2010/10/Pleistocene-moll_NL-550×275.jpg
Totally agree with anna v; it is illogical and misleading to average proxy temps together.
At best proxy data only gives trends – it cannot realistically give specific temperatures or CO2 contents or whatever other parameter being ‘assessed’.
Hence, to my mind, further averaging proxy data is like averaging the peoples of the world – yep – we are all human – but heck, our cultures are extremely different!
Your comment makes no sense. Run off and evaporation just move water from one part of the planet to another. The planet doesn’t lose water.
I didn’t read the meat of the article or any of the comments.
I’m happy to bask in the glow of real science starting to peek out of the totalitarian boot heel that describes the last 20 years of academia.
My name is Wright, feel free to call me wrong. I don’t hide from debate.
We all know who does.
The graph comes from Wikipedia which in turn comes from the Global Warming Art project prepared by Robert A. Rohde:
http://en.wikipedia.org/wiki/File:Holocene_Temperature_Variations.png
I’m a layman, not a scientist, but some one who is already seeing his electricity bills soar because of this CAGW nonsense. IMO anything on climate from Wikipedia must be taken ‘cum grano salis’.
At the bottom of the Wiki page is a most important caveat: “Though all of this data is published, and the methodology is similar to previously published methodology, and resulting average is similar to previously published interpretations of the Holocene, even so, no peer reviewed scientific publication has ever combined precisely these data in precisely this way. Hence, any interpretation of that average must be regarded with skepticism”.
I’m always suspicious of Wiki’s “thick dark line[s]” — in this case, as in the ‘hockeystick’, it is meaningless.
How can the average of a bunch of arbitrarily chosen proxy curves mean anything when grafted on to an instrumental series or, in this case, with the current (at the time of preparation) instrumental value stuck on?
Bulbhead
Sorry, you are misinformed, the general belief (by climate scientists) is that climate and Co2 has been relatively stable through the ages until we came along, increased CO2 and changed the climate.
http://www.metoffice.gov.uk/climatechange/policymakers/policy/slowdown.html
Extract “Before the twentieth century, when man-made greenhouse gas emissions really took off, there was an underlying stability to global climate. The temperature varied from year to year, or decade to decade, but stayed within a certain range and averaged out to an approximately steady level.”
tonyb
” bublhead says:”
?
It doesnt.
It was farting polar bears and walruses, innit?
Sorry I havent read through the comments. But it might pay to save that wikipedia Holocene temp graph for before it meets with a few Wiki edits. One wonders how it has survived intact for so long.
Greenland ice-core dating based on 10Be, the current standard, may be unreliable due to contamination . Even cores from neighbouring boreholes can be vastly different, which may be reason why many of proxies give contradicting results.
I have looked into the recent 10Be data, used by Dr. McCracken for calculating the heliosphere strength, and found that even as recently as Dalton minimum there could be significant errors.
More details available 10Be ? .
Somebody tell the EPA that the polar bears will be fine. Wait, they don’t care.
If there have been periods of ice free summers in the central Arctic Ocean in the early Holocene, I hazard to suggest that there have been other periods of ice-free summers in more recent times:
http://omniclimate.files.wordpress.com/2009/03/fig01.gif
” bublhead says:”
So how does this research fundamentally challenge the basic conclusions of Climate Change/Global Warming
http://wattsupwiththat.com/2010/10/30/might-arctic-warming-lead-to-catastrophic-methane-releases/
Might Arctic Warming Lead to Catastrophic Methane Releases?
Apparently not
If there is less ice isn’t there therefore more water vapour?
Jason F (2010/10/31 at 2:51 am)
You asked about increase in water vapour – I was refered to a paper the other day in commments on another thread:
“The central role of diminishing sea ice in recent Arctic temperature amplification” http://www.nature.com/nature/journal/v464/n7293/full/nature09051.html
The paper measures up to 10% increase in humidity (June-Oct) in the period 1989-2008.
Malaga View says:
October 31, 2010 at 12:56 am
Aha, back to classical old fashion plain science now? Looks so much more familiar!
But, alas, the patients are controlling the asylum now. We were busy slaving away, paying our taxes and supporting our familys.
Sorry.
If the value s of the ice-core data in the graph are correct, than the CO2-concentration 12000 years before present was below 250 ppm. Life would no longer exist on earth, because all plants stop assimilation, when the CO2 concentration falls below that value.
‘TJA says:
October 31, 2010 at 2:12 am
Somebody tell the EPA that the polar bears will be fine. Wait, they don’t care.’
How will those polar bears survive an ice free Arctic? How will they find their there favorite meal, seals? Or will they invade Montreal looking for easier pray?
Could we herd them toward Washington?
nc 12:20 am:
I followed the link you gave about the Piri Reis map. At the bottom of the page there’s a section entitled “Modern analysis of the Piri Reis map – Surprising Conclusions” and shortly afterwards a ‘read more’ link to the rest of the article which quite comprehensively debunks the claims that earlier map-makers had modern knowledge and technology that was subsequently lost.
“At the far right of this plot it is possible to observe the emergence of climate from the last glacial period of the current ice age. ”
Do you mean left?
John M Reynolds
Anthony,
You could definately have warmer temperatures and the trade off would have been less atmospheric pressure. But only to a point. The interesting link with water and salt is that the oceans have been becoming fresherwater over time due to the planetary slowdown and centrifugal force.
Follow the yellow brick road, follow the yellow brick road, follow, follow, follow, follow, follow the yellow brick road……..to the past.
Global warming scientists say the Arctic has never been ice free but it is going to be ice free because of global warming. Now that a peer reviewed work shows far less ice in the Arctic than now, and it’s not the first to do so, global warning believers say it’s a meaningless paper—it doesn’t (or the won’t let it) change what they believe.
You see, nothing will change religious zealotry. Blind faith is blind.
You can see that nothing will change their mind. Proof of strong negative feedback from H2O didn’t change their mind. ClimateGate didn’t change their mind. If those two things didn’t change their mind then one could conclude they don’t want to change their mind.
“The Americans are not here. We are pushing them back. We are cleaning them out.”
–Baghdad Bob
” and calls for further research on causal links between Arctic climate and sea ice.”
Ah ha! Must be budget time.
The longest running Ice Core:
http://www.robertb.darkhorizons.org/TempGr/Vostok.JPG
says that we have begun to round down the slope into the next Ice Age.
It was also (from the same graph) very stable at the end of the previous Ice Age as well as during the Holocene.
Ditto for the previous Ice Age and Interglacial. So much so, that it’s a very good probability that we have (as some suggest) already entered the beginning of the end of the Holocene Interglacial.
Each Ice Age is different, and it’s very obvious from spending time with Ice Core runs that there are 2 major waves that, over hundreds of thousands of years, have merged to form the Greater Interglacials, and are now pulling apart to form the Lesser Interglacials.
Looking for a 2nd peak in this Interglacial? Not the best odds, not at all.
@bublhead,
The point is that it was warmer, the Arctic icecap was gone, and the Earth did just fine.
Whatever forced the changes during the study period, loss of the icecap did not trigger, as AGW theory claims, a run away disaster. Polar bears seals whales and walrus all did fine.
And the increased temps did not cause a tipping point of run away positive feedbacks.
The methane did not bubble up from melting permafrost and poison life or cook the planet.
The point is that AGW- the idea that we are facing a global climate disruption due to CO2- is not supported by the history.
Is that something you are willing to deal with or will you seek to avoid the topic?
My quick thoughts based on the post are:
1. The artic in an ice free condition was not a risk, even to polar bears during the early Holocene. Today it would be a benefit to mankind and even polar bears.
2. The rate of the temp increase to the peak temp of the Holocene ~8,000 yrs ago was more dramatic than that of the last 150 yrs. Mankind and biodiversity did not end ~8,000 yrs ago. Ahhhh, quite the contrary, it flourished.
3. We are slowly sliding into the next glacial period, relentlessly but very very slowly. So no catastrophic ‘we are all going to freeze’ headlines, please. We have had enough of the ‘burn’ hype . . . . . ‘freeze’ hype is not an alternative option.
4. The graphic entitled “Holocene Temperature Variations” in the post is an upside down hockey stick with the handle pointing at the future Apparently Mother Nature is a hockey fan. : )
5. The temps at ~8,000 yrs ago were, conservatively, approximately of the order of the last 30 yr. It is hard to tell with that tiny inset when compared to the bigger chart. And the CO2 concentrations were not comparable to today’s higher levels. There was another cause operative in the Holocene. So Milankovic effect in combination with other effects did give natural cycles that were higher than the total of all of the speculations of current mankind effects and . . . . . . the world did not end; it thrived.
My unborn great-great-great grandchildern are smiling at me from my resident DNA.
John
On the same page as references, is the abstract for this supporting paper:
Temperature and precipitation history of the Arctic Original Research Article
Quaternary Science Reviews, Volume 29, Issues 15-16, July 2010, Pages 1679-1715
The Last Glacial Maximum (LGM) peaked not, vert, similar21 ka ago, when mean annual temperatures over parts of the Arctic were as much as 20 °C lower than at present. Ice recession was well underway 16 ka ago, and most of the Northern Hemisphere ice sheets had melted by 6 ka ago. Solar energy reached a summer maximum (9% higher than at present) not, vert, similar11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1–3 °C above 20th century averages, enough to completely melt many small glaciers throughout the Arctic, although the Greenland Ice Sheet was only slightly smaller than at present. Early Holocene summer sea ice limits were substantially smaller than their 20th century average, and the flow of Atlantic water into the Arctic Ocean was substantially greater. As summer solar energy decreased in the second half of the Holocene, glaciers re-established or advanced, sea ice expanded, and the flow of warm Atlantic water into the Arctic Ocean diminished.
So the Arctic sea ice extent vaties with temperature and Arctic temperature varies with solar radiation and the ice free period in the early Holocene is due to orbital changes. This says nothing about today except that the fall in sea ice extent is due to an increase in Arctic temperature.
So polar bears survived all this holecene warmth? Even in an ice-free Arctic the polar bears didn’t all drown?
My my how the eco-zealot lies are unraveling.
“Nothing travels faster than light, with the possible exception of man-made climate change, which follows its own rules”.
Thanks verity jones for the pointer 🙂
Now we all know what our dead corpses will turn into…as good and conscious skeptics we will contribute to future methane powered big SUV´s!!
Buy more popcorn!
The mission of climate scientists is now clear. They have to get rid of the early Holocene, too.
If that was true, it doesn’t mean that CO2 (if it causes lots of warming) won’t cause ice free Arctics in Summer, it does invalidate the assertion that CO2 is the primary driver of temperature and that it would be a “death spiral.”
Clearly, I would like to see more supporting evidence of this idea before I accept it just like all of the “science” supporting CAGW. Everything needs to be corroborated now.
Some posts here tend to be somewhat Northern Hemisphere-centric; to assert that the Northerners and the Chinese ‘invented ships’ is a simplistic and silly statement, as ships and shipping were not ‘invented’ but evolved over a very long period of time around the world. Some cultures evolved faster than others, and in different initial directions. Because some cultures were literate much earlier than others this allowed those early-adopters of literacy to archive their history, as the Norse peoples did of their settlement of Greenland and parts of the coast of Vineland in North America. After Capt James Cook blazed a trail into the Southern Pacific into Melanesia and Polynesia in the 17th century, contact with the native peoples there did not result in Europeans discovering any significant historical record as those Southern cultures transmitted their histories orally and thus were taken little notice of as Westerners believed that writing trumps speech.
There is a solid body of evidence that those Southern Pacific peoples also ‘invented ships’ (large twin-hulled sailing canoes) and ustilised them to colonise or trade with many points around the Pacific Rim during the warmer MWP and the Roman Warm Period, traversing vast tracts of the Pacific Ocean and making deadfall landings at the end of such traverses.
There are many historical oddities and question marks everywhere, such as the great Lewis and Clark expedition to the Pacific coast of North America discovering a tribe of large and fair-skinned native people with reddish hair, who used what appeared to be Welsh coracles for fishing on their rivers, round boats woven from Willow and covered in hide or felt, the paddles of which were incised with what appeared to be Welsh or Breton inscriptions. That people, according to Lewis and Clark, also followed religious practices that seemed to be a very rough approximation of Christianity.
anna v wrote: “You have taken the wiki page for the first figure, and the data come from
The following data sources were used in constructing the main plot:
[a long list of references]
I have an objection with averaging proxy temperatures coming from different proxies and different locations.
As we see in the plot , there are much larger variations than the average shows. If each curve, because of the methodology is out of phase or its calibration with temperature is not stable over the years ( as with tree rings, other factors at other times might influence the proxy analogue) averaging them is like mixing cold soup with hot soup.
”
Quite right.
“One should look at the individual curves and how they compare with the present .”
Absolutely.
Or, hold one’s nose, and at least provide error bars in both the x and y axes for the average plot [why does climate science, unlike every other field of science, typically not show error bars and/or provide quantitative estimates of uncertainly?]
To Anna V: I agree with you completely. Mixing proxies (which is a key strategy for creating hockey stick handles) is bad science. I can think of several analogies in electrical engineering and I’d be deservably fired for doing any of them.
As someone commented those in the little ice age must have thought that was normal. Global warming advocates think climate should be stable, fixed in time to suit their needs and desires. And they will do almost anything to bring that about.
The problem I see, and others in comments, is global warming advocates have framed the conversation on CO2 directing a lot of the energy in research in a narrow focus. Like tunnel vision missing the big picture. And climate researchers who oppose that focus have been suppressed and ridiculed.
CO2 is a bitch, you can’t live with it and sure as hell can’t live without it. And it is difficult to understand but to put the blame on CO2 for everything is like kicking the dog because some chickens are missing. CO2, like the dog is taking the blame when the problem could be the farmer miscounted the chickens.
The way this will be spun by the AGW alarmists, of course, is that if it got that hot with low CO2 levels, that high CO2 levels on top of this means we’re all going to diiiiieeee!!! The a priori assumption is always that CO2 is proven to drive temperature, of that no doubt will be brooked, so anything that indicates high temps without high CO2 levels will never be examined the way it should be, that is as disproving the idea that CO2 is the one main driver of climate and temperature. It will be read as another factor that’ll add, or multiply, to the “known” CO2 effect, assuring gloom, doom, death, and destruction. It will never force a reexamination of their core beliefs.
Ian H says:
Your comment makes no sense. Run off and evaporation just move water from one part of the planet to another. The planet doesn’t lose water.
Well, I’ll admit to getting to verbose about it, but all I am really saying is that it is credible to believe that the Sun can control climate by causing changes in the hydrological cycle.
Robert in Calgary,
Its comments like yours Robert that just dismiss the work of all of those published climate scientists who have been coming to the same basic conclusions for decades now that give climate change deniers a bad name.
If the study that is the basis of this discussion somehow challenges or disproves the IPCC conclusions, tell me how, don’t just sit back with a smirk on your face telling me that all those published climate scientists are involved in some sort of global conspiracy to distort science so that we can destroy the global economy or something.
As an aside, thanks for the links to the two organizations you support. I have supported a number of small businesses through Kiva micro credit loans and the organizations you support look to be doing great work. I will look into them and perhaps support them as well.
And I agree with Anna V., but even in single proxies like the Vostok core, there appear to be two levels where stability (roughly) occurs. One is during Ice Ages, the other during interglacials. What changes in those periods of stability?
MartinGAtkins
As much use as I make of Wikipedia as a starting point in my research, it isn’t actually a primary source. The article you referenced is written (and probably continuously edited) by lots of people, some of whom probably have an agenda.
Your comment seems to revolve around this statement
“Wild swings of CO2 have always been shown to be the result of and not the cause of climate changes and extinctions.”
While I don’t deny this, I would be interested in some citations but the point of the IPCC science is that human activity is pumping green house gases (primarily CO2) in such volumes as to overwhelm other factors like the Milankovitch Cycles. Human activity has become a factor. We are pushing CO2 into the atmosphere in far greater volumes than natural sources. It can’t been seen as a surprise that doing so will cause the environment to do things it hasn’t done in the past.
So I guess I return to my earlier question, how does this study challenge or disprove the fundamental conclusions of Climate Change?
Which is kind of what you asked as well:
“As the article says CO2 has been lower through the Holocene epoch even when temperatures have been much warmer than now.
Why?”
I guess my first answer would be that things like our place in the Milankovitch cycles are different than they were then. Everything that I have seen says that current and projected levels of CO2 are higher than they are at any point than we can identify in history. And that unnaturally high level of CO2 is currently overwhelming all the natural drivers to the cycles of global climate.
Does this study somehow challenge that understanding?
And yet polar bears, ringed seals and bearded seals survived as species. This does not mean some of them did not die. But we know that animal populations can take quite a hit and still bounce back (e.g. sea otters, northern fur seals, grey whales, elephant seals, etc.).
These animals are adapted to the Arctic, which means they feed heavily in the spring and early summer (when they develop thick layers of fat). This fat allows polar bears to fast during the low-ice summer months (Hudson Bay bears routinely fast for 4 months and do just fine) and seals to fast while they give birth (in the spring) and moult (in the early summer). At the height of the summer ice loss period, none of them really need ice to survive.
I expect “ice-free” really just meant a few weeks in September. By November ice would have been back.
@QA_NJ
Don’t expect to hear much from Mike Mann for a few weeks. He is probably busy inventing new ways, previously unknown to statisticians, to torture data until…voila!…the Holocene has ceased to exist.
I hope Steve McIntyre hasn’t got any immovable long term plans and that Anthony Montford (Bishop Hill) has a good supply of sharpened pencils.
bublhead — So how does this research fundamentally challenge the basic conclusions of Climate Change/Global Warming?
It doesn’t.
I read your blog post, and with all due respect, you’re a narrow minded bigot.
Non-skeptics are focused on “it’s an impending disaster” where “impending” ranges from “it’s too late, we’re already screwed” to 5 years to a century or more. But the “it’s an impending disaster” meme is unyielding: the sky is falling, and the only question is when.
Skeptics have a wider bandwidth, ranging from what you would call lukewarmers “GW is happening, man contributes, but it’s not a disaster” all the way to the “it’s a conspiracy” crowd. You attack the silly 15% minority viewpoint because it’s exceedingly simple to do and then uncreatively (all of your ilk manages the same stupid pet trick) attempt to spin the viewpoint, strawman style, as that representing all skeptics. The scrotal torsion alone from that amount of spin could sterilise an elephant.
Most of the people posting on this blog fall into the “lukewarmer” group attempting to understand and ultimately extricate the usable science from the vapid spinning and screeching of the chicken little crowd (i.e. YOU.) That you are unable to distinguish between those who are coldly and rationally examining evidence and those who are rejecting evidence out of hand is quite telling: in the manner of “birds of a feather” you can only identify the antipodal viewpoint thus indicating that you buy the alarmist party line without critical thought. If you were actually a thinker, you’d be more inclined to grasp the underlying skeptical approach and write thusly. But, you don’t, meaning you can’t.
Have another smurfy day in screechland.
Repeat after me: “stable systems don’t have tipping points”
It appears it has all happened before.
http://climateaudit.org/2009/05/03/is-chu-for-real/
GL Alston
” The scrotal torsion alone from that amount of spin could sterilise an elephant.”
Haha. nice one.
It is my great desire that more an more people learn this simple approach.
Once you say these words the whole debate changes.
” C02 warms the planet, we just don’t know how much”
That changes the debate for the following reasons.
1. Bulbheads dont know how to respond. They are used to their party line.
( skeptics deny the effect of C02, skeptics are anti science, balh blah blah)
2. The argument shifts to the weakest link of their argument where they have
INTERNAL discord.
I don’t know why more “skeptics/denialists” don’t see this.
EVEN IF you believe that C02 has no effect, EVEN IF you believe that, you are FAR BETTER OFF, saying ” C02 warms the planet, we just dont know how much”
Hello Uncle Walt,
I said nothing at all about a “global conspiracy to distort science”. We have a theory that has very little credible science to back it up.
I’m sorry if I’m not providing enough “meat” in my comments. I have found that I can spend large amounts of time putting together posts for folks such as yourself.
I find that AGW fanatics tend to move the goalposts a lot and engage in a lot of “tapdancing”. I don’t want to spend that much time dealing with tapdancers.
Manmade global warming fanatics have had over 20 years to make the case scientifically. You didn’t have the science so you tried to shout down people with “The debate is over!!” and “Scientific concensus!!”
Al Gore is a massive hypocrite, so is David Suzuki. We supposedly have a planetary crisis and these two live the good life while lecturing everyone else.
Over 20 years and you haven’t made the case. Rational folks might say it’s because the science to backup the theory isn’t there.
Ideally, manmade global warming fanatics would come to their senses, admit they really got it wrong, then we could all turn to really helping people and the situations on this planet who need our help.
Not only the proxies should not be added, but if they are based on the Greenland glaciers ( google GRIP project), the latest and the most praised 10Be records, then proxies may be highly suspect!
Here I show direct copy of 10Be data from
A 600-year annual 10Be record from the NGRIP ice core, Greenland
by Berggren et al. from
GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L11801, doi:10.1029/2009GL038004, 2009
Received 6 March 2009; revised 20 March 2009; accepted 1 April 2009; published 2 June 2009.
http://www.vukcevic.talktalk.net/CET&10Be.htm
The 10Be data is inverted and superimposed with the CETs.
Anyone in contemporary science will tell that can’t be.
Either solar output is directly responsible for the temperature variations (except for miner deviations between Greenland and central England)
or 10Be Greenland glaciers (GRIP project) data are useless.
Perhaps Anthony could ask Dr. Svalgaard to explain the mystery.
One thing that has become clear in recent years is that past weather and climate analogs may give hints of what our weather patterns have done in the past, but they will not yield exact predictions. Here is where anthropogenic effects may come into play. The Great Plains are far different place now than in 1750; large scale destruction of jungles in Indonesia (in order to farm ethanol producing palm trees) and the Amazonin the long run produce different global weather patterns today than in 1350. We simply do not know.
What governs Artic sea surface temperature variations is simple (prevailing winds and ocean currents). What drives these components is far more difficult to ascertain than our Alarmists will admit. If for some reason the ocean currents that provide warmer tropical and subtropical waters to the poles would be cut-off or diverted, polar sea ice would increase immediately, and strong, deep polar air masses would drive the mid-latitude climate. Hot dry summers and bitterly cold dry winters would dominate. All without the help of changes in greenhouse gases. But consequently, what goes up must come down. In order to maintain a proper balance (or heat budget), teleconnections between the equator and poles would certainly create extreme weather and climate variations on the fringes. This is what occured over Europe during the LIA. The LIA there was known more for its extreme variations in temperature and precipitation patterns . The NAO and AO produced a pattern of wide climate variability no matter what occured in the subtropics. Perhaps an unknown teleconnection existed or was amplified by some unknown parameter. We do know that the changes in the NAO were amplified a very strong belt of mid latitudinal baroclinicity across the North Atlantic. We also know that Greenland, Iceland, Scandanavia and the North Sea cooled. And these conditions persisted for over 500 years.
The main point is to go by what we do know. It is too bad this bit of knowledge is clouded by not only misinformation and revisionism, but also by shodding statistics, poor theory, and the retention of important data for political purposes (see Lonnie Thompson and his ice core data). There is so much we do not know, that one would think there would be a more transparent push to get the truth investigated.
The potential for ice-free summers in the Arctic is not new – Astrid Lysa from the Geological Survey of Norway reported some years back on research into beach-structures on northern Greenland that indicated ice-free conditions and were dated at about 8000 BP.
It doesn’t throw a great deal of light on the debate (other than there was no ‘tipping point’ – which is of course important) because the Holocene Optimum is generally recognised as having been induced by orbital cycles. I am not convinced that the rather rapid rise out of the ice-age at about 11,000BP can also be explained by oribital cycles – the rise seems too abrupt and it also coincides with proxies for geomagnetic and solar magnetic disturbances.
Thus, there has been a natural cooling since then – with roughly 1000yr cycles of warming and each succesive peak being lower. It could be argued that the late 20th century peak in the northern hemisphere would have been lower still without CO2 bumping it up a bit!
bublhead says:
October 31, 2010 at 8:34 am
As much use as I make of Wikipedia as a starting point in my research, it isn’t actually a primary source. The article you referenced is written (and probably continuously edited) by lots of people, some of whom probably have an agenda.
You said “I don’t think that they conclude that it was always the major forcing factor.”
Google “co2 extinctions” and you will find more than enough references to nearly all the extinction events by some “scientists”.
Your comment seems to revolve around this statement
“Wild swings of CO2 have always been shown to be the result of and not the cause of climate changes and extinctions. While I don’t deny this, I would be interested in some citations”
You could start by accepting that the interglacial periods were driven by warming first and CO2 followed by some 800 years. Then do some leg work and show me a period when CO2 led to climate change or mass extinctions.
the IPCC science is that human activity is pumping green house gases (primarily CO2) in such volumes as to overwhelm other factors like the Milankovitch Cycles.
Milankovitch Cycles act over longer or as long as the Holocene epoch. They don’t explain the peaks and troughs of temperature during the last 1100 or so years.
Look at this graph. The last temp peak and trough on the left hand side they are the Middle age warming and the Little ice age. You will see throughout the Holocene, temperatures have fluctuated wildly and cannot be attributed to CO2 or Milankovitch Cycles.
http://i599.photobucket.com/albums/tt74/MartinGAtkins/GISP_to_11Kybp.gif
We are pushing CO2 into the atmosphere in far greater volumes than natural sources. It can’t been seen as a surprise that doing so will cause the environment to do things it hasn’t done in the past.
I’m not just being pedantic but the climate never does exactly what it’s done in the past. We live in a chaotic environment and it has and will always be so.
And that unnaturally high level of CO2 is currently overwhelming all the natural drivers to the cycles of global climate.
Whilst it can’t be said that the extra CO2 has no effect it equally cannot be said that it overwhelms all the other drivers. There is no empirical evidence that it is making any meaningful difference to our climate.
Does this study somehow challenge that understanding?
It challenges the concept that the present low NH ice levels are in anyway unique.
I’ve added an inline response to Richard Telford upstream.
richard telford says:
“The conclusions of this paper are entirely reasonable – you will be hard pressed to find any palaeoclimatologists who are surprised that sea ice extent was lower in the early Holocene.”
The late, great John Daly wrote on pretty much the same thing, an ice-free Arctic.
The Arctic has been ice free countless times over the past 10,000 years. It is called “natural variability,” and if CO2 has any effect, it is too insignificant to be measurable. Many other so-called forcings overwhelm any putative CO2 effect. Face it, you can’t pick out your supposed CO2 effect from past or current natural climate fluctuations. It all looks the same. [<— this is a Phil Jones chart].
Richard sums up:
"Ice doesn’t particularly care whether it is warm because of high insolation or high CO2 levels."
Richard, when ice is warm we have a different word for it: "water." And if CO2 is the cause of Arctic ice melting… prove it. Or at least provide convincing, testable, reproducible evidence showing that is so, and empirically quantify the percentage of melting ice due to increased CO2. Do that and you will be on the short list for the next Nobel prize [for whatever that is now worth]. The fact is that the claimed connection between CO2 and Arctic ice is pure conjecture, nothing more.
By
robustlyrigorously adhering to the scientific method – with all raw data, methodologies and metadata provided upon request to skeptical scientists – try to show us convincingly that CO2 is the main climate driver. If you can.Natural climate variability within the parameters of the Holocene explains all observations of the current climate. Nothing unusual is happening, despite all the alarmist hand-waving. Regional climate constantly changes, but the globe’s current temperature is well within the bounds of past extremes. In fact, today’s climate is extremely benign. Nothing unusual or exceptional is occurring due to CO2.
Alarmists contort themselves trying to prove that CO2 has a measurable effect on the temperature. But the null hypothesis, as described above, has never been falsified – while the alternative hypothesis, CO2=CAGW, has been repeatedly falsified, not least by the planet itself.
The day the alarmist contingent decides to follow the scientific method is the day that their CO2=CAGW hypothesis goes down in flames. And they know it, which is why they hide from the scientific method like Dracula hides from the dawn. If followed, the scientific method would destroy them and derail their gravy train.
My post crossed with Anthony’s above. It would have saved me some typing if I had seen his detailed rebuttal. MartinGAtkins makes good points too, as do others.
And whatever happened to that thingy called “sublimation”? If the relative humidity is low, and there is wind, sublimation occurs. So long a this planet rotates on its axis, there will be wind.
As to the H2O molecule, it would be better, for understanding, that H2O molecules never travel alone. Heat baggage travels along with them, the quantity dependent on the state or phase, that is, the solid state, the liquid state, or the vapor state of H2O. When there is a change of state, heat baggage is either greatly increased or decreased on a molecular basis; the heat baggage has to either come from somewhere, or go somewhere with a change of state, or phase change, of H2O. H2O is one of the two great heat movers on the planet, moving heat from the equatorial regions in the direction of the polar regions.
The other great heat mover is the Coriolis effect, which moves colder water from the polar regions to equitorial regions, displacing warmer equatorial waters in the direction of the polar regions. Within the polar regions, huge amounts of heat are radiated away from Earth into space, and corresponding huge amounts of heat are radiated to equitorial regions from the sun. H2O is the vehicle that transports massive quantities of heat around.
As for CO2, greater concentrations of it in the atmosphere increase green plant growth and vice versa. There is such a small concentration of it in the Earth’s atmosphere, it is clear to me, at least, that it can have little if any effect on the overall temperature of Earth. Other forces overwhelm it as a driver of temperature. With less of it, there will be less food for all animal life to eat, and vise versa, no more.
CO2 has become the bugaboo of alarmists, only because by alarmist methods, great sums of money can be made, Follow the money, every time.
Mind all, I am a mere civil engineer, but lo, those many years ago, I did learn the fundamentals of chemistry, and physics; statics and dynamics, thermodynamics, and electrical, along with appropriate courses in mathematics. It has been more than 50 years since I attended college and university, back when there was no more than fundamentals to be taught, and professors of chemistry and physics were determined that their students learned those fundamentals of chemistry and physics well.
I have been a “science buff” from a very early age, and having a huge idle curiosity of all things of a scientific nature, I have also, from my own efforts, “kept on top”, as best I could and can do, of all advances in most all scientific fields of endeavor, just for my own edification.
I might also add, that I had good success, through necessity of income, in sales as well, and I do know a confidence artist when I hear one speaking or read the writing of one, and this CO2 bugaboo is, without question, no more than a confidence artist’s game.
So many assumptions are included in the mix, on which the speculations of AG warming, AG climate change and AG climate disruption are dependent, a good many of which have been falsified , that I am amazed that anyone who understands scientific method takes it seriously at all. Only the desire of government grant money could drive this parody of science.
‘Tis a pity that there now seem to be only “specialists” and “experts” in the sciences anymore, or at least heard from nowadays. Where have the generalists of science gone, the equivalents of the giants of science of yesteryear, who made such wonderful and important discoveries that actually advanced scientific knowledge greatly? No government grant money for them, I would only guess.
you do not have to go back 8000 yrs to see a major change for ice in the artic
http://pubs.aina.ucalgary.ca/arctic/Arctic37-1-49.pdf
ABSTRACT. The release of a dead but well-preserved higahr ctic plant community, entombed for about 400 radiocarbon years (WAT-778 and 789)
under glacial ice at TwGinl acier, central Ellesmere Island (78″53’N7,5 35%)’ is reported. Remarkably intact plants have been emerging from under
the ablating front of this polar glacier which has been retreating for several decades at an average rate of 4.1 m.yr” over the last 22 years. The
vegetation can be readily recognized as a Cassiope terragona-Dryas integrtfolia-dominated community, similar in species composition and cover to
an extant Cassiope-Dryas community 200 m below the ablationf ront. The excellent preservation of the plants supports the thesis that polar glaciers
are frozen to their bases, and hence their movements are by internal deformation rather than by erosive basal sliding.
——————–
http://hol.sagepub.com/content/17/8/1069.abstract
Columbia V5A 1S6, Canada
Abstract
Holocene glacier fluctuations prior to the `Little Ice Age’ in Garibaldi Provincial Park in the British Columbia Coast Mountains were reconstructed from geomorphic mapping and radiocarbon ages on 37 samples of growth-position and detrital wood from glacier forefields. Glaciers in Garibaldi Park were smaller than at present in the early Holocene, although some evidence exists for minor, short-lived advances at this time. The first well-documented advance dates to 7700—7300 14C yr BP. Subsequent advances date to 6400—5100, 4300, 4100—2900 and 1600—1100 14C yr BP. Some glaciers approached their maximum Holocene limits several times during the past 10 000 years. Periods of advance in Garibaldi Park are broadly synchronous with advances elsewhere in the Canadian Cordillera, suggesting a common climatic cause.
and for those who want to say that the MWP was only NH
http://www.clim-past.net/5/375/2009/cp-5-375-2009.pdf
Abstract. The rapid expansion of the Inca from the Cuzco
area of highland Peru (ca. AD 1400–1532) produced the
largest empire in the New World. Although this meteoric
growth may in part be due to the adoption of innovative
societal strategies, supported by a large labour force and a
standing army, we argue that it would not have been possible
without increased crop productivity, which was linked
to more favourable climatic conditions. Here we present a
multi-proxy, high-resolution 1200-year lake sediment record
from Marcacocha, located 12 km north of Ollantaytambo, in
the heartland of the Inca Empire. This record reveals a period
of sustained aridity that began from AD 880, followed by increased
warming from AD 1100 that lasted beyond the arrival
of the Spanish in AD 1532. These increasingly warmer
conditions would have allowed the Inca and their immediate
predecessors the opportunity to exploit higher altitudes
(post-AD 1150) by constructing agricultural terraces that employed
glacial-fed irrigation,
More from the Holocene.
Could it be in the cycles?
A Pervasive Millennial-Scale Cycle in North Atlantic Holocene and Glacial Climates
Climate Change in Eurasian Arctic Shelf Seas
Holocene Sea-Ice Variations and Paleoenvironmental Change, Northernmost Ellesmere Island, N.W.T., Canada
It *could* be in cycles but I believe there is a very clear and steady cooling trend for the past 2000 years or so. Yes, that trend is punctuated by periods of warming and cooling but each warm period seems to have been a little cooler than the previous and each cooling period cooler than the previous.
We can talk about these cycles of warming and cooling superimposed on that trend but I believe the real issue is that trend and I have seen nothing from the 20th century warm period that breaks that trend. It still appears that this warm period is cooler than the MWP. The LIA was the coldest period since the Younger Dryas. This is the coolest “warm period” we have had in a long time.
Long term cooling trend from Vostok ice cores: click Current temperatures are not unusual, nor is the rate of increase.
Take a look at what I’ve just found:
and
Added to the above post this means that it’s much, much worse than we thought. :o)
Climate science believers would do well to avoid making arguments like
“it’s unprecedented”
Even if you believe it to be true, it’s a bad argument. That should be apparent on its face.
Anthony, your argument seems to have not to subtly changed.
The uninformed reader could have assumed from your previous text that the cause of the early Holocene warming was unknown, perhaps part of internal variability. Why else should the paper be a “formidable monkey wrench”?
Now you are arguing that orbital forcing at 65N was an order of magnitude higher in the early Holocene that CO2 forcing is today. This is completely different argument. Is this an admission that the earlier argument could have been misread? But is also misleading. First, it shows the radiative effect CO2 in 2000. This effect will be higher by the end of the century. Second, it ignores the slightly reduced early Holocene winter insolation. More importantly, it ignores the impact of feedbacks. A global radiative forcing and a forcing with a near zero global average cannot be expected to cause the same feedback. Further, it ignores the possible duration of the sea-ice period in the early Holocene, which may be longer than that forecast for the end of this century.
REPLY: Sorry, your argument fails to convince, especially since the “feedbacks” issue is, ahem, still up in the air. Bottom line, you’ve offered no evidence that CO2 is driving changes in Arctic ice then or now. – Anthony
In answer to crosspatch, I would just say that the forcing from doubling CO2 (3.7 W/m2) is seven times larger than the estimated solar-change forcing at the Maunder Minimum (-0.5 W/m2 derived from the solar data at climate4you for example) that drove the Little Ice Age. This is just comparing forcing, not considering feedbacks that would amplify both. I think this puts it into a perspective that is not often recognized.
richard telford says:
October 31, 2010 at 3:46 pm
“The uninformed reader”……..
==============
No uninformed readers here, they/we come here to be informed.
We may be unwashed, but we are not uninformed.
Anyone who hasn’t read it should – “The Secret of Atlantis” by Otto Muck. Atlantis was destroyed 10,000 BC by the comet Adonis IV which also caused teh biblical deluge (and the mass freezing of mammoths). Anyone taht even doubts this for one second will have their mind blown when they read the book. The Atlantis destruction event was THE event that ended the last age. There is absolutely NO DOUBT.
[Reply: Perhaps you should take this comment over to Climate Progress, where it would be more appropriate. ~dbs]
Hunter,
I guess I am not sure what you mean by “the the Earth did just fine.”
The disaster scenarios that come from global warming, as I understand them, involve increased volatility of the weather, significant changes in precipitation patterns globally, and rising sea levels worldwide that threaten low lying areas where millions of people live.
The loss of Artic ice in the summer has its own positive feedback mechanism because the loss of ice changes the albedo of the polar region so more energy is absorbed by the (darker) water instead of being reflected by the more reflective ice.
I don’t know what study you are referring to that claims that loss of Artic Sea Ice triggers the disasters as much as loss of Artic Sea Ice being a result of Global Warming.
So I still don’t see how a period 10000 years ago when it was warmer than it is now and the Artic Ocean was ice free part of the time challenges the basic conclusions of Global Warming.
CO2 is not the only driver of heating and cooling cycles. Other factors such as the Milankovitch cycles had impacts as well.
But when you pump unprecedented levels of CO2 into the atmosphere, it’s not illogical to consider that the effect of those levels of CO2 might large enough to overcome all the factors that have governed climate cycles in the past.
The same thing applies to methane releases. Some models suggested that as the globe gets warmer, there could be massive releases of Methane into the atmosphere. Though it doesn’t appear to be happening as yet, nothing that has happened makes such releases impossible as the warming trend continues. Maybe the methane releases are yet to come.
Your conclusion:
“The point is that AGW- the idea that we are facing a global climate disruption due to CO2- is not supported by the history.”
Misses the point. We are dealing with CO2 levels much higher than any time in history and the effect of those CO2 levels overrides the trends and triggers we might be able to discern from the record of past cycles.
There are a LOT of assumptions in those numbers that have not borne out in actual observation. The assumption that feedback would be positive is a major one and the amount of forcing that CO2 actually provides is another. Neither of those have been shown to be true. They are basically little more than guesses. IF the forcing from CO2 is as that researcher thinks it is and IF the resulting feedback (if any) are positive (there is more observational data that the feedback is negative!) then yes, maybe. But to state it as if it is some sort of truth is intellectually dishonest.
This is an interesting study, but there is a logical fallacy (not made in the study by the way) in drawing a conclusion that just because CO2 levels may not have been the driver behind a warmer Arctic during the Holocene Optimum, that they couldn’t be the driver behind a warmer Arctic now. This is exactly the same logical fallacy that looks at the longer term CO2 levels and warming periods and draws the false conclusion that just because CO2 levels SOMETIMES followed a rise in temperatures in the records, that rising CO2 levels cannot cause a rise in temperatures in and of themselves. There can be many different causes that lead to the same effect, and there is no logical or justifiable reason to draw the conclusion that the existence of one precludes the existence of others.
hunter says:
October 31, 2010 at 5:50 am
@bublhead,
The point is that it was warmer, the Arctic icecap was gone, and the Earth did just fine.
Whatever forced the changes during the study period, loss of the icecap did not trigger, as AGW theory claims, a run away disaster. Polar bears seals whales and walrus all did fine.
And the increased temps did not cause a tipping point of run away positive feedbacks.
The methane did not bubble up from melting permafrost and poison life or cook the planet.
The point is that AGW- the idea that we are facing a global climate disruption due to CO2- is not supported by the history.
Is that something you are willing to deal with or will you seek to avoid the topic?
I could not agree more with that summary and have posted, on numerous occasions, similar comments. Whilst I have real concerns regarding the so called ‘science’ behind AGW, and concerns regarding the accuracy and reliability of the collation of the temperature record during the instrument period, what I find most surprising about the theory is the prophesies of doom that accompanies a warming world. History simply does not support those prophesies. In fact not only did man survive a warmer planet, he greatly flourished during such periods. The birth of modern civilisations occurred during the warm Holocene period (8,000 to 3,000 bp). Historically, the only Northern civilisation of note is the Vikings and it is no surprise that they flourished during the MWP. If only proper studies into the geological and historical record were carried out, it would soon become apparent that warm is good and cold is bad.
Whilst I do not believe that man is significantly impacting on climate (and to the limited extent that he may be doing so, this probably mainly due to land change uses in which I include UHI), I can see no evidence that a planet warmer by 2° or 3° or 4° C will be a bad thing and I am unaware of any sound scientific evidence supporting runaway forcings..
“We are dealing with CO2 levels much higher than any time in history and the effect of those CO2 levels overrides the trends and triggers we might be able to discern from the record of past cycles.”
Really? What do you mean by “history” here? Just curious. Your comment does not make any sense either way, but it would help if you were precise in your writing.
I assume that you take the models that even the IPCC warns against placing too much faith in at face value?
Can you provide me with evidence that man-made co2 was responsibe for the late 20th century reduction in Arctic sea ice extent?
Do you have evidence that the 2007 minimum extent (satellite records since 1979) was casued by man-made co2?
Please bear in min NASA who have put the blame on wind and currents. They also point to soot.
http://www.nasa.gov/vision/earth/lookingatearth/quikscat-20071001.html
http://www.nasa.gov/topics/earth/features/warming_aerosols_prt.htm
http://www.pnas.org/content/101/2/423.long
bublhead says:
October 31, 2010 at 5:05 pm (Edit)
Hunter,
I guess I am not sure what you mean by “the the Earth did just fine.”
The disaster scenarios that come from global warming, as I understand them, involve increased volatility of the weather, significant changes in precipitation patterns globally, and rising sea levels worldwide that threaten low lying areas where millions of people live.
The loss of Ar[c]tic ice in the summer has its own positive feedback mechanism because the loss of ice changes the albedo of the polar region so more energy is absorbed by the (darker) water instead of being reflected by the more reflective ice.
I don’t know what study you are referring to that claims that loss of Ar[c]tic Sea Ice triggers the disasters as much as loss of Ar[c]tic Sea Ice being a result of Global Warming.
So I still don’t see how a period 10000 years ago when it was warmer than it is now and the Ar[c]tic Ocean was ice free part of the time challenges the basic conclusions of Global Warming.
CO2 is not the only driver of heating and cooling cycles. Other factors such as the Milankovitch cycles had impacts as well.
Regrettably, almost each of your sentences needs correction/comment:
“The disaster scenarios that come from global warming, as I understand them, involve increased volatility of the weather, significant changes in precipitation patterns globally, and rising sea levels worldwide that threaten low lying areas where millions of people live.”
Not true. Each of these Dire Predictions is based on nothing more than an assumed and extrapolated linear curve of temperature into to the far future (50 – 150 years) based on simplified models that have failed to predict accurately even the near-term (15 year) future based on even their own linear and compounded CO2 level changes that themselves assume no changes in culture, technology, and energy production methods. (Based on 1908 technology, how long, how wide, and and thick should I build a runway for the airplanes that will be flying in 1948?) These predictions are made for the purpose of publicity and fear-mongering to raise taxes and to make ALL energy artificially more expensive. Nothing more. The CAGW theorists and their UN/IPCC partners are doing this for their money, their power, their glory.
Rising sea levels? How about 1/4 inch per year? There is no real-world hazard from rising sea levels. What has been seen is no different than the rates seen before CO2 began to rise. And the BENEFITS of rising CO2 levels are (deliberately) ignored by the CAGW profit-makers: more food, more fodder, more fuel, more farms, more more wood, more shelter, more greenery, more plants, more drought-resistant plants, and even longer growing seasons in more areas due to the natural 800-year warming cycle we are near the peak of today. Changing precipitation patterns cannot be established nor accurately predicted. The Sahara was green only a few thousand years ago. Changing precip patterns? Yes, they may occur. But the CAGW theorists cannot predict their own past, much less any future.
“The loss of Ar[c]tic ice in the summer has its own positive feedback mechanism because the loss of ice changes the albedo of the polar region so more energy is absorbed by the (darker) water instead of being reflected by the more reflective ice.”
Please substantiate this oft-repeated claim. Tell me the angle where sunlight reflects from the ice. Tell me the angle where sunlight reflects from the ice. Tell me the area you assume is ice-free in which summer months. Tell me the difference in heat absorption between a supposedly “dark” sea and a “white”ice field when the sun’s angle is 23 degrees from the horizon. Tell me the difference in absorbed heat based on the number of km’s that sunlight penetrates. Justify your claim for this charade. But use numbers valid for the Arctic.
Don’t use the areas covered by land. (They are already ice-free all summer months.) Don’t use absorption criteria based on the temperate climates or near-tropical sun angles. Don’t use 24 hour solar days when only a limited part of the Arctic sees 24 hour days for only limited numbers of days per year. Show me your numbers for this oft-repeated Arctic solar feedback claim. [And,please, spell Arctic correctly. 8<) ]
“So I still don’t see how a period 10000 years ago when it was warmer than it is now and the Ar[c]tic Ocean was ice free part of the time challenges the basic conclusions of Global Warming.
CO2 is not the only driver of heating and cooling cycles. Other factors such as the Milankovitch cycles had impacts as well.”
Milankovitch cycles are drivers over long-term periods of time (25,000 to 120,000 years). No CAGW/CO2 theory can explain the 800 year observed cycle of +/- 1.5 degree temperature changes. No CO2 theory can explain the observed and measured 60 year short term temperature cycle. ANY previous Arctic Ocean times when it was ice-free proves that today's warmer temperatures and lowering ice extents merely proves that you cannot explain the natural cycles that have always been present. We are in an 800 year long-term cycle. We are warming from the low temperatures of the mid-1650's. No one denies that truth – so YOU must explain why we have been warming for 350 years without CO2 and for 50 years with CO2 at the same rate. (Adding a 60 year short cycle of course – that YOU cannot explain either.) And YOU cannot do that.
And, if you cannot explain natural cycles when CO2 was NOT varying due to human causes, your assumed CO2 – driven cycles today based on a recent 20 year rise in CO2 levels are also dead wrong.
G.L. Alston
Thanks for reading my blog. I am always looking for new readers. Did you leave any comments? I got three new comments on my “These people are Nuts” post (http://bublhead.blogspot.com/2010/10/these-people-are-nuts.html). I hope you were one of them.
I wonder if you read the comments thread following my post because I think I addressed your concern. If you didn’t I will quote it here.
“ . . . the community of published climate scientists all uniformly agree on three basic tenants of this science.
The globe in getting warmer (the current warming cycle started before the industrial revolution) and is warming now faster than at any time in history.
Human activity is putting Green House gases, particularly CO2, into the atmosphere in quantities that dwarf all natural sources combined and is driving the concentration of CO2 in the atmosphere to level never before seen.
Those Green house gases are the principle driving factor behind the pace of the increase in global average surface temperature.
The devil is in the details. Depending on whose model you use, the earth will either heat up by between 1 and 5 degrees this century. 1 degree is bad. 5 degrees is catastrophic.
There is no remaining debate in the scientific community about the basics of global warming. There is a wide range of possible outcomes with the resulting wide range of costs, but the basics are known.”
I think that is actually not in conflict with your statement that “Skeptics have a wider bandwidth, ranging from what you would call lukewarmers “GW is happening, man contributes, but it’s not a disaster” all the way to the “it’s a conspiracy” crowd.”
Personally I don’t consider your Lukewarmers as Climate Change Deniers or Skeptics or whatever term you want to use. Its clear to me that past the three basics, there is little agreement on the sensitivity of the climate to CO2 or whether this will lead to a massive release of Methane or if it will shutdown the North Atlantic Circulator or if it will be bad but not catastrophic at all.
The basic are, I believe, settled. The details are not. Which is, I believe, in line with what you were saying. I don’t know that we actually disagree all that much.
The discussion here is one of the reasons I like this blog for this topic. Most conservative oriented blogs are purely deniers, global warming isn’t real, mankind isn’t doing it, temperatures have started to decline or any number of other insanities. This blog actually discusses the science.
I like that
That is why I posted my original comment and its question.
Which I still think is an open question. What in the study that was the subject of the original post, challenges any of the basic conclusions of IPCC?
I look forward to a good discussion.
As an aside, I like the way you write and wonder if you have your own blog that I could start reading?
crosspatch, I only talked about forcing, not feedback, for a reason. Even Monckton, Lindzen and Spencer agree with the 3.7 W/m2 forcing for doubling CO2 (there really is consensus on that number). Now considering the equivalent number for the Maunder Minimum, it is only -0.5 W/m2. This is just to give the most easy comparison with recent historical events, because a problem so far is that people don’t have a reference point for the 3.7 number.
The open water during that time is not really new. Studies by Dyke on Bowhead Whalebones have indicated that to be the case. The western and eastern Bowhead populations could meet 9-10,000 years ago. Likewise the drift wood carried by Transpolar Drift to Svalbard, by Hoggblom 1982, has indicated 4 periods of high percentages open water much greater than today. The driftwood and whale bones study actual suggest that the past 100- 800 years, coinciding with the LIttle Ice Age, as a period of less typical sever ice. This paper is further confirmation.
re:
I beg to differ. In science one must always have a null hypothesis. When it comes to CO2 AGW, that null hypothesis is natural causes. If you cannot show scientifically how the new hypothesis, e.g., AGW, somehow explains the recent temperature increases far BETTER than natural causes, then the null hypothesis is by definition the correct answer. In order to show that man produced CO2 explains things better, you would also have to be able to explain how we got similar temperature increases, similar rates (sometimes apparently even faster and larger increases) in the past when man wasn’t producing any significant amount of CO2, or didn’t even exist. Until that can be done, logically, and until proven otherwise, the temperature increases are of natural origin.
This is how we’ve managed to come out of the dark ages (that and a nice temperature increase giving us a much more hospitable world! :0) ) – by using our nifty tool of science in order to weed out assumptions, guesses, human error, and human bias to the greatest extent possible. In science, applying the tool correctly is crucial – otherwise, well, the earth is flat, we get sick from vapors and evil spirits, the universe and sun revolve around the Earth, and so on.
The null hypothesis is always king – ALWAYS – until the new hypothesis can be scientifically proven to fit all known data and facts significantly better than the null hypothesis does.
Thank you, racookpe1978 for your post of October 31, 2010 at 6:00 pm replying to bubblehead where you said:
“Regrettably, almost each of your sentences needs correction/comment”
I thought about replying several times and gave it up for that very reason. Where to even start when there are so many misconceptions and logical errors.
R. Gates says:
October 31, 2010 at 5:20 pm
True, but this sort of study does do two things…
First, it quiets the people that claim that the Arctic hasn’t been ice free in the past 100+ thousand years, see:
http://tamino.wordpress.com/2010/10/16/anthony-watts-pants-on-fire/#comment-44936
Second, it provides evidence that losing the (summer) Arctic sea ice isn’t the world-killer that the CAGW crowd seems to scream. As a person that believes in (some of the) AGW but not in the CAGW rantings, I consider this study very important.
-Scott
Is there a consensus on whether the impact of Milankovitch forcing increasing or decreasing? If not, what are the opinions?
“you’ve offered no evidence that CO2 is driving changes in Arctic ice then or now.”
Has anybody ever argued that changes in CO2 at 10kBP was an important forcing?
RobertInAz says:
October 31, 2010 at 10:08 pm
The orbital dynamics behind Milankovitch forcing are well understood, but the details of how the changes in insolation affect climate are not completely understood.
Milankovitch are more important in redistributing insolation by latitude and season than they are in affecting global averages. Milankovitch forcing also changes very slowly – it is important on millennial timescales, not decadal.
Insolation values can be obtained from
http://www.ncdc.noaa.gov/paleo/forcing.html
That’s not how I read that graph.
Here is one including more recent studies:
[MOD COMMENT – no link given – mj]
Driftwood and whalebone studies have suggested that around 10-9000 years ago the Arctic had a lot of open water. Then there Rapid Climate Change leading to cold temperatures and severe ice conditions. Those driftwood studies and ice core studies all suggest alternations at millennial time scales between periods of severe ice and high percentages of open water. Mayewski (2004) also reviews the Arctic ice core data that reveal several periods of Rapid Climate Changes where temperatures drop, often by several degrees in a few decades.
When Dr. Mark Serreze posted recently here about the state of Arctic Ice, he referred to a paper he co-authored “The History of Arctic Ice” 2010 Polyak et al., where they state “the severity of present ice loss can be highlighted by the break up of ice shelves at the northern coast of Ellesmere Island (Mueller etal.,2008), which have been stable until recently for at least several thousand years based on geological data (England et al.,2008).”
Maybe Serreze and the others were striving for dramatic effect by selectively using highly speculative geological data (driftwood data). Or perhaps it was their advocacy , that has taken their science to the dark-side. But their portrayal of the Ellesmere Ice Shelf stability simply stretches the truth. Most studies shown tremendous climate variability over the past 10,000 years with sudden rapid coolings followed by warming, not 5000 years of stability! So I investigated the validity of their claim.
First, Polyak and Serreze’s claim that the Ellesmere ice shelves have been stable for 5000 years, ignores the well documented calving of 600 km2 of the Ward Hunt Ice shelf in 1961. (Holdsworth, 1971) It also ignores the 1946 document existence of a 700 km2 ice island that was determined to be part of the Ellesmere ice shelf. These early dates are prior to the dates when the disastrous effects of CO2 are purported to first attacked the Arctic, and suggests natural variation and natural causes. But lets assume that the 194 break up was due to global warming.
The sole basis for Serreze and Polyak’s 5500 years of stable ice shelf claim, is based on the absence of driftwood behind the small section of the Ellesmere Island Shelf. So their claims needs a some background info to understand and evaluate.
The potential for driftwood to land on Ellesmere Island is a function of 3 factors. 1) How much sea ice is available to carry the wood, 2) Shifts in the sea level pressures and wind patterns that can alter the Transpolar Drift. This effects the current’s ability to deliver wood to Ellesmere island that would more typically go out the Fram Strait and to Svalbard, and 3) Access to Ellesmere Island beaches. An Ice Shelf or multiyear ice (ice shelves are just thicker multiyear fast ice) can block driftwood access landward of the ice. But open water is not absolutely necessary to access the beaches as icebound driftwood can be pushed over the fast ice.
Due to the way currents transport driftwood in the Arctic, Svalbard receives orders of magnitude more driftwood than Ellesmere or other places in the Canadian Arctic Archipelago. And therefore Svalsbard provides better sample sizes and a more sensitive indicator of overall Arctic sea ice changes. Haggblom 1982, published the classic study of driftwood patterns on the islands of Svalbard. Using studies from the timber industries, he created a table of maximum time driftwood could stay afloat before its increased density due, to water-logging, would cause it to sink. Amongst the conifer trees, Spruce trees could stay afloat up to 17 months while Larch and Pine trees could stay afloat 9-10 months. Hardwoods with different xylem tissue, like Birch, Aspens and Willows stay afloat only 6-10 months. Also, the larger the trunk (due to smaller surface-to-volume ratios) the more slowly it became waterlogged. Likewise the presences of bark or how dry the wood was initially affected the rate of being waterlogged.
Then based on known speeds of currents Haggblom estimated that it would take 5 years for driftwood to reach Svalbard after being flushed from Siberia or other boreal forests in to the Arctic waters. Since the maximum time before sinking was 17 months, if the Arctic waters were ice free, all logs would become waterlogged and sink before reaching Svalbard. In order for the driftwood to reach Svalbard wood had to become frozen into the pack ice, raised above the water-line, and transported via ice floes for most of its journey. Thus the amount of driftwood, the species and size of the driftwood, can serve as proxies suggesting concentrations of Arctic sea ice vs open water, while C14 dating and the elevations zones where the wood is deposited, suggest the age within about 100 years error bars.
Haggblom characterized patterns of Svalbard driftwood into general times of severe ice, moderate ice and high percentages of open water. But even within those time spans, he detected a lot of variability. For example, the zone that corresponds from the present time to about 800 years BP, is littered with various lines containing abundant driftwood in many-sized pieces from conifers and hardwoods, The presence of the remains unique to Siberian vessels known as “lodja” or “sitji” helped date parts of this line. The abundant driftwood and lack of Bowhead whale bones, suggested severe sea ice conditions, but these were alternating with less wood suggesting less severe ice conditions a. In accord with the Svalbard time lines, there is the Little Ice Age where there were at least three cold periods around 1650, about 1770, and 1850, with intermittent periods of slight warming.
From that zone, there is an abrupt transition. Hoggblom dated that net driftwood zone to range between 800-1700 BP.He suggested that the Arctic experienced mostly open water because in stark contrast to the earlier zone of abundant driftwood, this was relatively empty of driftwood with only a few large Spruce or Larch trunks. However there were whale bone lines in this zone. This all suggested a warmer period and high percentages of open water. This suggestion is supported by an abundance evidence centering the Medieval Warm Period between 950 and 1200 years BP. Archaeological evidence indicates the Norse and Thule cultures moved into Greenland and Ellsmere Island during this time.
This warm period is also suggested in paper Serreze and Polyak actually cited by Anderson “A highly unstable Holocene climate in the subpolar North Atlantic: evidence from diatoms” in which the authors equate current Arctic temperatures to a period 1600 years ago, which is also the time indicated in Svalbard by no driftwood suggesting high percentages of ice free ocean.
Further examining of the paper they referenced, (England 2008), raised few more suspicions. England(2008) presents a map of the Ellesmere Island with locations of dated driftwood, and the location of the Ellesmere Island Ice Shelf as it is believed to have existed in 1906, and which they suggest had been stable for over 5500 years. Polyak, Serreze et al state “An even longer perspective for the outstanding magnitude of the modern warming and related ice loss is provided by the history of ice shelves at the northern coast of Ellsemere Island, which are made of super-thickened landfast ice supported by pack ice in the adjacent Arctic Ocean. These ice shelves have been stable for most of the last 5.5 kyr based on driftwood ages(England etal.,2008)”
In England (2008) they show the extent of the 1906 ice shelf would have covered Clements Markham Inlet. When showing the time periods of dated driftwood they state “In Clements Markham Inlet a temporary cessation occurs approximately 3500 cal yr BP, after which driftwood re-enters intermittently to the present.” However the phrase “re-enters intermittently to present” actually refers to just a few samples dated between 1900-2100 years ago, followed by a several hundred year absence of driftwood, until a few more samples that were dated to what appears to be the last hundred years.
So by England’s own analysis, the whole Ellesmere Ice shelf as defined in 1906, was not intact for 5500 years, at least not around the Clements Markham Inlet when the driftwood landed a few different times during that time span.
Furthermore the absences of driftwood at the Clements Markham Inlet after 3500 years, and between 500 and 1900 years ago, dates also correspond to the broad time periods of warm open waters from the Svalbard data. This suggests that during those corresponding times, driftwood was not available to any parts of Ellesmere. Therefore the lack of driftwood may not infer the presence ice shelves that blocked beach access. A more likely speculation, since Svalbard data corresponded to warmer open water, is that the ice shelves were likely reduced or absent, and despite potential access, there was no driftwood able to reach the beach’s.
Finally the sparse Ellesmere driftwood and dates is insufficient to provide any evidence of decadal fluctuations in ice cover. Often there were several hundred years between driftwood dates. Thus fluctuation less that 100 years would not be reocgnized.
So England’s conclusions about a stable ice shelf must be viewed as speculation at best. Furthermore England’s speculative conclusion was mostly referring to the Ward Hunt Ice Shelf which is one small section of the Ellesmere Shelf . But Polyak and Serreze in attempt to show the “severity” of the current ice decline, not only make the speculation about Ward Hunt Ice Shelf stability appear certain , they expand this to include the whole Ellesmere Ice Shelf stating “These ice shelves have been stable for most of the last 5.5 kyr” . There is a hint of missing integrity here by these authors of History of Arctic Ice.
We have been told by the Warmists that there would be an Arctic feedback loop. That is that the more sea ice retreats each year, the more dark sea is exposed, the more heat is absorbed leading to less ice next September and so on….
This feedback loop has been shown in this post to have not kicked in during the Holocene despite ice-free central Arctic ocean. Does this mean that this theory for the Arctic is false? Is my question valid? Am I missing something? Comments appreciated.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VBC-51509K7-1&_user=10&_coverDate=10%2F02%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1520547417&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=4864f509bd7183b0f225da2036305798&searchtype=a
http://wattsupwiththat.com/2010/10/30/new-peer-reviewed-paper-says-there-appear-to-have-been-periods-of-ice-free-summers-in-the-central-arctic-ocean/#comment-520353
I have done a write up related to this as well. I tie in a variety of other factors as well.
http://theinconvenientskeptic.com/2010/11/nh-summer-energy-the-leading-indicator/
John Kehr
The Inconvenient Skeptic
Scott says:
October 31, 2010 at 9:18 pm
R. Gates says:
October 31, 2010 at 5:20 pm
There can be many different causes that lead to the same effect, and there is no logical or justifiable reason to draw the conclusion that the existence of one precludes the existence of others.
True, but this sort of study does do two things…
First, it quiets the people that claim that the Arctic hasn’t been ice free in the past 100+ thousand years, see:
http://tamino.wordpress.com/2010/10/16/anthony-watts-pants-on-fire/#comment-44936
Second, it provides evidence that losing the (summer) Arctic sea ice isn’t the world-killer that the CAGW crowd seems to scream. As a person that believes in (some of the) AGW but not in the CAGW rantings, I consider this study very important.
-Scott
_____
I wouldn’t disagree with your general statement and my statement was simply to point out that one cause does not in any way preclude another so that those sceptics who would insist that this kind of study proves that CO2 can’t cause warming.
We know that CO2 levels are up 40% since the 1700’s and furthermore, that they are at their highest levels in at least 800,000 years. The central question is only a matter of sensitivity– both in the amount of CO2 as well as the relatively rapidity with which the levels have grown (geologically speaking). Human activity over the past few hundred years represents essentially a continuously “CO2 volcano”, and for anyone to suggest that just because the earth may have been warmer in the past when CO2 was not this high, says nothing about what kinds of effects the speed and levels of CO2 in our modern era might cause.
R. Gates says: October 31, 2010 at 5:20 pm
This is an interesting study, but there is a logical fallacy (not made in the study by the way) in drawing a conclusion that just because CO2 levels may not have been the driver behind a warmer Arctic during the Holocene Optimum, that they couldn’t be the driver behind a warmer Arctic now.
They need the positive feedback of water vapour to cause the catastrophic rise in temperature the AGWers believe will happen, it does not matter what caused the rise in temperature in the past, without the positive feedback of the main greenhouse gas water vapour there is no catastrophe, it didn`t happen in the past warmings and it will not happen in future warmings. CO2 can`t do it on its own.
This is nothing to do with the arctic but what caused this warming.
http://i446.photobucket.com/albums/qq187/bobclive/swissglacier.jpg
I have to agree with anna v, dumping data from all over the world into a “Shake and Bake” bag and attempting to draw any logical conclusion about a single region like the Arctic isn’t logical.
All the studies I’ve read related to this fascinating era indicate the temperature change was far more extreme in the NH. Unfortunately, very little ice core analysis has been done on the Alaska glaciers or if it is available, I haven’t been able to locate it.
One recent study postulated the importance of the Bering Strait as one of the triggers for the glacial shifts. The Bering Strait is 49M at its lowest point and the drop in Pacific Ocean depth at the glacial maximum was approximately 150M. IPCC cites 120M which is in dispute and may be corrected in the next report.
Salinity in Arctic waters via the Bering Strait has also been attributed to the Arctic Ice minimum in 2007. I believe the statement was, it accounts for more than half of the ice melt in 2007.
Ice free Arctic during this period isn’t supported by sediment samples taken at/near the North Pole however the samples indicated ice free conditions from earlier periods.
A 150M drop in Ocean levels, decreased fresh water Arctic input from a dryer Siberia and lack of Bering Strait input, dryer conditions would promote evaporation, Glaciers and sea level drop cutting off a significant portion of the Canada discharge from the Arctic, as well as higher salinity, and additional exposed land mass along the Siberian coast would have all contributed to declining summer ice formation.
As far as I can tell, CO2 had very little to do with glacial changes — was a byproduct of temperature change.
Interesting aside: there is also evidence of human hunting artifacts in Alaska dating to 13-14k BP and Mammoth remains well within the Arctic circle above Alaska and on islands off the coast of Siberia.
Anyone have historical cloud data that shows the current warming cannot be attributed to changes in cloud cover?
…
…
…
No? No support for the attribution to CO2?
rbateman:
Thanks for the link to the 800,00 yr. Vostok graphic. I will add it to my standard 400,000 year graphic that came from Frank Lansner’s article in WUWT. And, if one scrolls down to the last graph of this article, you find that an ice core collected by NOAA, about 10,000 miles from the Vostok core, shows similar results. Namely, that we insignificant little humans had better prepare for a coming ice age.
If the sun, as Mr. Lansner posits, should go into a 1,000 or 10,000 year solar minimum, what might then happen? Will it matter at all what CO2 or water vapor or anything else has to do with the current warming?
I find it striking that on any of these proxy temp/CO2 graphs, that the vast majority of time during the last 400 or 800 thousand years has been spent well below the -2 degree centigrade variance from the current optimum (if I understand that correctly). Can anyone say “Ice Age?” Chicago under a mile of ice? No, wait. That’s nuts according to the aptly named “bublhead”. All I know is, as a technically oriented non-scientist, and a very visually oriented person, those graphs practically shout out that we are living in a warm period that is on borrowed time. We may be in the start of a 10,000 year solar minimum (or whatever the hell may cause the next temp decline), or it may not happen for another 10,000 years. Either way, this insistence on CO2 as the driver seems nuts to me. It is just a very successful diversion created by unscrupulous businessmen and their political cronies, to elevate them to powerful positions and riches that will assure their continued power. But hey, we should be grateful that they are trying to take care of us little guys, right?
http://www.robertb.darkhorizons.org/TempGr/Vostok.JPG
It is too bad there is no real way to get the H2O content of the atmosphere from the ice cores. I’ll bet that H2O goes up before CO2. As more water moves to liquid phase and becomes available for the hydrological cycle, CO2 is released from the oceans and ice packs. And this fooled some paleo types into thinking it was a driver and not a passenger. Still, there seem to be two levels of stability that correlate with whether ice is in liquid or solid phase.
I just stumbled onto this website by accident but I wanted to say a couple of things. First of all I wanted to say that I have read somewhere that before 2 millions years ago we had a period of several million years where we didn’t have any ice ages. And then there was a period before that where we did have them. I guess that is long term. I also wanted to say that if someone fills a glass up to the brim with ice and ice water, and then allows the ice to melt, the level of the liquid will be lower in the glass than it was originally with the ice in it. Is science so sure that ocean levels were lower during the ice age? One final note to Darren Parker: I plan on looking up this “The Secret of Atlantis” by Otto Muck. I know that there is another book out there by a person from India that says that Atlantis was in the South China Sea and sank beneath the waves because of the volcano Krakatoa.
Anthony, you are a funny man. I will not argue the quality of your interpretation. This is not the place.
I’ll just point something that academics consider somewhat important.
You quote in your title that “there appear to have been periods of ice free summers in the central Arctic Ocean”.
The paper instead says “there appears even to have been periods of ice free summers in large parts of the central Arctic Ocean”.
“Quoting is serious business”.
Several papers have suggested that there is a 1400-1500 year cycle, and since the warm period around 10,000, years ago there have been periodic cold snaps in the Arctic seemed to correspond with this time span.
Keeling for whom the CO2 curve is named after, in addition to warning about increased CO2, noticed climate changed due to natural causes that affected temperature and CO2. He noticed strong forcing, consistent with observed temperature periodicities, occurred at 9-year intervals close to perihelion.
http://www.pnas.org/content/94/16/8321.abstract
He also proposed that the larger 1400 cycles were due to a rectified lunar tidal forcing. The tidal affected the vertical mixing bringing cold water to the surface and thus effecting climate dynamics.
http://www.pnas.org/content/97/8/3814.abstract
I believe it was discussed here a while back.
Dave F says: It is too bad there is no real way to get the H2O content of the atmosphere from the ice cores. I’ll bet that H2O goes up before CO2.
Looking at it from the other pole, the South Pole is one of the driest places on earth. The do experiments on long wave radiation there to help eliminate cloud and water vapor effects. So with H2O out of the way, inland enough to take oceanic influences out of the equations we have a natural experiment where you can see the trend in temperature due just CO2 and whatever unknowns left over. Nature’s South Pole experiment shows significant cooling trends, despite the CO2
Slightly OT, but relevant to ice conditions in the early Holocene. Motl discusses it here:
http://motls.blogspot.com/2010/07/in-defense-of-milankovitch-by-gerard.html
(The links to the pdf on Motls page don’t seem to be working right now.)
This is a pretty important paper, IMO. Look at Fig 2 & 3 in the pdf. There is a remarkable statistical correlation between June solar insolation at 65 deg north and ice-volume changes — 99%! You almost never find such close correlations in climate science. To me, this leaves little room for any CO2 effect in the north polar regions as far as ice-volume changes go. Motl agrees.
This is interesting, because as this generally well accepted graph shows, temperature was higher then.
Clearly it doesn’t, to the contrary it shows temperatures are higher now!
beng says:
November 2, 2010 at 8:03 am
Slightly OT, but relevant to ice conditions in the early Holocene. Motl discusses it here:
http://motls.blogspot.com/2010/07/in-defense-of-milankovitch-by-gerard.html
(The links to the pdf on Motls page don’t seem to be working right now.)
This is a pretty important paper, IMO. Look at Fig 2 & 3 in the pdf. There is a remarkable statistical correlation between June solar insolation at 65 deg north and ice-volume changes — 99%! You almost never find such close correlations in climate science. To me, this leaves little room for any CO2 effect in the north polar regions as far as ice-volume changes go. Motl agrees.
Since the links don’t appear to work I haven’t been able to check that but the Motl page talks about ‘rate of change of ice volume’ and ‘June insolation at 65ºN’ but his graphs don’t show data more recent than about 10kyears ago.
Phil. says:
November 2, 2010 at 8:56 am
This is interesting, because as this generally well accepted graph shows, temperature was higher then.
Clearly it doesn’t, to the contrary it shows temperatures are higher now!
=========
And, there it is in a nut shell : )
The tendency of Climate Science drifts to the child-like as it attempts to attribute Global conditions to regional anomalies. How can anyone claim something is Global in Nature when the nature of the system has always achieved a balance at its most extreme points?
Phil., here’s a link that I got to work for the Roe paper:
http://earthweb.ess.washington.edu/roe/Publications/MilanDefense_GRL.pdf
[Note: TinyURL compresses URL’s to manageable size. Easy to use: http://tiny.cc ~dbs]
Nope, that works from the Yahoo search page, but not embedded in this page — sorry. A quick search should bring up a working link to the pdf — it did for me.
beng says:
November 2, 2010 at 8:03 am
This is a pretty important paper, IMO. Look at Fig 2 & 3 in the pdf. There is a remarkable statistical correlation between June solar insolation at 65 deg north and ice-volume changes — 99%! You almost never find such close correlations in climate science. To me, this leaves little room for any CO2 effect in the north polar regions as far as ice-volume changes go. Motl agrees.
Thanks for the working link, on quibble with your post, it isn’t a statistical correlation of 99% it’s “The SPECMAP record has zero lag and HW04
record is lagged by only 1 kyr, in order to show the maximum lag correlation with the
insolation time series of –0.8 and –0.4, respectively. Autocorrelation estimates suggest that the SPECMAP and HW04 time series of dV/dt have 106 and 123 degrees of freedom respectively. Therefore, in both cases the correlations are significant at well above the 99% confidence level.”
Mr. Watts:
The research study referred to above does not support a conclusion that increases in CO2 radiative forcing have not contributed to a decline in Arctic sea ice.
The abstract from the study states that it is to be used for comparison of “potential future changes in Arctic climate under scenarios of global warming”. The abstract does not say that CO2 does not contribute to current global warming or that current CO2 levels are not contributing to the recent multi-decade decline in Arctic sea ice. If the study makes such a claim, then please provide the direct quote and citation. The abstract stated:
“One important motivation for studying the amplitude of past natural environmental changes in the Arctic is to better understand the role of this region in a global perspective and provide base-line conditions against which to explore potential future changes in Arctic climate under scenarios of global warming.”
The study provides a basis for challenging assertions made by some AGW proponents that current Arctic sea ice extent does not have any comparable historical precedent during the Holocene. It also challenges assertions by some AGW proponents that there have never been periods of ice free summers in the central Arctic Ocean during the Holocene. Neither of these assertions are necessary to support the theory that CO2 and other anthropogenic radiative forcings are contributing to the current observed decline in Arctic sea ice.
That the Arctic could achieve higher temperatures than we are currently experiencing (through higher TSI radiative forcing or changes in cloud cover) without adding any CO2 to the atmosphere is “old news”.
While CO2 levels are not the focus of this study, there is a large body of literature that supports the theory that increases in CO2 radiative forcing and the other anthropogenic forcings have contributed to the current ice decline and will contribute to future declines in Arctic sea ice.
Any implication that this study “throws a formidable monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss” is false. While it is appropriate to make fun of silly phrases such as “Arctic Death Spiral”, this does not require the use of false assertions or the poorly constructed logic used to support the “monkey wrench” conclusion. The data concerning prior conditions is a useful starting point to an analysis of current conditions. The prior conditions reflect changes to the Arctic caused by changes in TSI and other non-anthropogenic forces, such as changes in cloud cover. However, if the specific forces which created the prior condition or “natural variability” are not identified, it is unclear how this information can be used in understanding the impact of current forces on the Arctic sea ice.
Mr. Watts:
I have found a copy of the paper “History of sea ice in the Artic” and the assertion in the posting above that:
“This new paper in the journal Quaternary Science Reviews throws a formidable monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss.”
is such a piece of disinformation that whoever wrote this line must not have read the paper or is deliberately distorting the information contained in the paper.
Contrary to the post, section 4.4 of the paper supports the theory that the increase in atmospheric green-house gas concentrations is a major contributer to current Arctic sea ice loss.
“4.4. Recent warming
Arctic paleoclimate proxies in lake and marine sediments, tree rings, and icecores indicate that from the mid-19th century the
Arctic not only warmed by more than 1 C average in comparison with the‘‘LittleIce Age’’(Overpecketal., 1997), but also reached the highest temperatures in at least the last two thousand years (Kaufman etal.,2009). This warming sharply reversed the long-term cooling trend that had likely been caused by the orbitally-driven decreasing summer insolation with the positive feedbacks from ice ands now albedo (e.g., Otto-Bliesneretal., 2006b). Subglacial material exposed by retreating glaciers in the Canadian Arctic corroborates that modern temperatures are higher than any time in at least the past1600 years (Anderson etal., 2008). An even longer perspective for the outstanding magnitude of the modern warming and related ice loss is provided by the history of ice shelves at the northern coast of Ellsemere Island,which are made of super- thickened landfast ice supported by packice in the adjacent Arctic Ocean. These ice shelves have been stable for most of the last 5.5kyr
based on drift wood ages (England etal.,2008), but declined by more than 90% during the 20th century and continue to break at a notable rate (Mueller etal., 2008).
An unraveled magnitude and duration of modern sea-ice retreat on a millennial background has been reported for the Nordic Seas based on combined ice core and tree-ring proxy data from Svalbard and Scandinavia (Macias-Fauriaetal., 2009). A comparison of this reconstruction with the Arctic-wide compilation of ice extent since the mid-19th century (Kinnardetal.,2008) shows a close match except for an obvious discrepancy in the early 20th century (Fig. 12). This discrepancy reflects the pronounced warming event in the Nordic Seas that was amplified by multidecadal variability of the North Atlantic circulation (Polyakovetal., 2009) and therefore affected primarily the Atlantic sector of the Arctic, somewhat similar to the15th-century warming anomaly(Crespinetal., 2009). In contrast, a very close match between the Nordic Seas and Arctic-wide records of ice extent during the recent decades emphasizes the pan-Arctic nature of the modern ice loss.
A climatic simulation by Sedla´cˇek and Mysak (in press) suggests that after about 1900 AD the slow increase in atmospheric green-house gas concentrations was the main driver of sea-ice changes in the Northern Hemisphere, while other forcings such as volcanic activity were mostly responsible for the thermodynamically produced changes in sea ice area and volume during the preceding four centuries. The remarkable modern warming and associated reduction in sea-ice extent are especially anomalous because orbitally-driven summer insolation in the Arctic has been decreasing steadily since its maximum at 11ka, and is now near its minimum in the precession cycle (Bergerand Loutre, 2004)”
The final paragraph of the paper concludes that the current Arctic ice decline is different from other declines that occurred during the Holocene:
“On suborbital timescales, ice distributions varied in the Holo-cene, but no evidence exists for large, pan-Arctic fluctuations.
Historical records indicate that Arctic sea-ice extent has been declining since the late 19th century. Although this decline was
accompanied by multidecadal oscillations, the accelerated ice loss during the last several decades lead to conditions not documented in at least the last few thousand years. Taking together the magnitude, wide geographic distribution, and abruptness of this ice loss, it appears to be anomalous in comparison with climatic and hydrographic variability observed on submillennial time scales and longer-term insolation changes.”
L. Polyaketal./QuaternaryScienceReviews29(2010)1757–1778 1772
For a summary of the paper, I refer you to the following link which was posted on September 8, 2010, which includes this statement from one of the authors of the paper:
When asked, “when was the last time the Arctic was ice free”, the lead author, Leonid Polyak, of Ohio State’s Byrd Polar Research Center, replied:
“The paleo data we have so far is very scant, so we can’t know for sure when the Arctic was ice free in the summer last time. To be conservative, the closest candidate is the early Holocene (roughly ~10 kyr ago), when the insolation in the Arctic was high due to the beneficial orbital configuration; however, the more data I see, the stronger is my impression that there was not that little ice at that time. The next best (actually, better) candidate is the Last Interglacial, about 125kyr ago, again due to orbitally-driven high insolation: the ice was likely very low, but we can’t say whether it was completely ice free in summer or not. There are also a few other major interglacials, which may have had a similar picture, in particular Marine Isotopic Stage 11, about 450 kyr ago. In any case we are talking about very rare events controlled by a forcing very different from today. If none of those intervals was really ice free, then a million year assessment would be correct.”
The final paragraph of the review anticipated the assertion so misleadingly made in the post above, when it stated:
“So the next time some anti-science disinformer — or more likely, one of the doubters who has been duped by them — says past warmth undermines our understanding of human-caused warming, tell them, quite the reverse is true. The paleoclimate record provides us more cause to be worried, not less. We know natural forcings led to warming in the past, but human emissions of greenhouse gases are overwhelming the climate now, and threatening catastrophic levels of warming if we stay on our current emissions path.”
http://climateprogress.org/2010/09/08/arctic-sea-ice-history-paleoclimate-polar-amplification/
While it is fair to disagree over whether the warming will actually be “catastrophic” and the extent to which AGW is “overwhelming the climate now” (please note, these hyperboles are also not supported by the paper), there is no need to fabricate an assertion concerning the paper which is so clearly contrary to the conclusions reached in the paper.
You may want to consider updating the posting referencing this paper.
Sorry about the reference to a different paper in Quarternary Science Reviews than the one cited in the post, but the general comment that the cited study providing data that “there appear to have been periods of ice free summers in the central Arctic Ocean” in the early Holocene, about 10-11,000 years ago and that this somehow throws a “monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss” is not supported by other research in the same journal.