Dr. Don J. Easterbrook, Western Washington University, Bellingham, WA
Miller et al. radiocarbon dated 145 rooted tundra plants revealed by receding ice in the eastern Canadian Arctic and contend that it constitutes the first direct evidence that recent temperatures now exceed those of any century in the Holocene, including the Holocene Thermal Maximum. They further contend that (1) average summer temperatures of the last ~100 years were higher than any century in the past 44,000 years and suggest that present temperatures have not been exceeded in the past ~120,000 years, at or near the end of the last interglaciation, and (2) they conclude that this ‘unprecedented’ warming was caused by anthropogenic increases in greenhouse gases. So let’s look at some of the assumptions that form the basis for their conclusions and compare their conclusions to other Arctic data.
Figure 1 A. Baffin Island showing sample sites. Circles (color-coded by their 14C age) show the 135, <5 ka, sites where rooted plants were collected at receding ice cap margins; diamonds show sites dated >47 ka. Solid lines mark the margins of the LIS at the last glacial maximum and 9 ka [A. S. Dyke, 2004]. B. Detailed map of sites older than ~45 ka.
Assertions and assumptions by Miller et al.
[1] Mille el al. contend that “although glaciers are frequently associated with deep and widespread erosion, small, cold-based ice caps that mantle relatively flat terrain typically advance by lateral accretion rather than by basal flow, and are thus capable of preserving even the most delicate features of the landscape. As these ice caps recede, they often reveal rooted tundra plants that were living at the time snow and ice last covered the site.” They further contend that “Surface-elevation contours of the continental Laurentide Ice Sheet (LIS) show that all four ice caps with pre-Holocene dated plants were above the surface of the LIS at its last glacial maximum. These sites thus supported only local ice caps then as now. And, because the ice caps occupy flat summits of less than 0.2 km2 surrounded by steep slopes, ice thicknesses of more than 70 meters could not have been sustained.”
The assumptions in these statements are:
a. Miller et al. assume that the ice caps are cold-based (i.e., basal ice is frozen to the ground below) and that there is no basal sliding of the ice and no basal erosion. However, deep fiords and ice-scoured scoured bedrock in the area attest to active subglacial erosion (i.e., basal sliding rather than frozen to the ground), although most of the obvious erosion is probably related to Pleistocene glaciation. The Greenland ice sheet just across the Davis Strait at the same latitude is not frozen to its base, and the average summer temperature at Clyde (north of the sample sites) is 3°C above freezing during June, July, August, and September (Fig. 5). Summer temperatures of all of the more than half dozen weather stations along the east coast of Baffin, where the sample sites are located, are above freezing during June, July, August, and September. Thus, the Miller et al. conclusion that the small ice caps in this study are frozen to their base is highly questionable and most like not true.
b. Miller et al. contend that the Laurentide Ice Sheet did not cover the area of the ice caps and that there has been no erosion since the Eemian Interglacial 120,000 years ago. However, the Laurentide Ice Sheet (LIS) extended eastward beyond this area to the coast (Fig. 1) and reconstructed ice surface elevations show the area to be close to the 1000 m and 2000 m contours, i.e., close to or above the present ice caps. The scale of the ice surface reconstructions is not detailed enough to show exactly how high the LIS surface was at the sites, but at least suggest a good possibility that the area was overridden by the LIS. The importance of this is their conclusion that the older sites have not been disturbed for 120,000 years, but to make this assertion they need to provide adequate evidence.
Figure 2. Reconstruction of the Laurentide Ice Sheet (Dyke, 2002)
c. The Miller et al. assertion that the ice caps were not more than 70m thick is highly questionable. The ice caps expanded noticeably during the Little Ice Age and even if the LIS didn’t overrun the ice cap sites, the ice caps must surely have thickened, especially since the surrounding lower areas were filled with LIS ice. Thus, their contention that the ice caps could not have been more than 70 m thick is most likely not valid.
[2] Miller et al. claim that recent exposure of moss by melting ice proves that modern temperatures at the site were as high or higher than at any time since the moss was covered by ice and that therefore present temperatures have not been exceeded in 120,000 years. But is this necessarily true? If a block of ice is placed on the floor of a room and the thermostat is turned to 90°F, the ice will begin to melt. If the thermostat is then turned down to 40°F before all of the ice has melted, ice will continue to melt until the floor is uncovered, but to conclude that the temperature had never risen above 40°F since the floor was first covered with ice would be totally false. The same is true of the Baffin ice caps—if moss is uncovered at today’s temperatures, that doesn’t mean that higher temperatures haven’t occurred previously. Thus, the Miller et al. conclusions that “temperatures of the past century must have exceeded those of any century in more than 44 ka” and “there has been no intervening century during which warmth exceeded that of the last 100 years” are illogical and badly flawed. One wonders how this bad logic got past peer review. In addition, we know from data in the Greenland GISP2 ice core that temperatures in Greenland rose more than 20°F per century at least three times in the past 15,000 years, well within the 120,000 years claimed by Miller et al. to have never been warmer than recently.
[3] Among the 145 14C dates on exposed moss in this study are10 dates ranging in age from 23,900 to 50,700 years, leading to their conclusion that temperatures today are the hottest in >50 ka and most likely in the past 120 ka. They explain the disparity between these old dates and the multitude of young Holocene dates as due to higher elevations of the older samples so the younger sites could be exposed by melting of ice while the higher, older sites remained ice covered. But as shown by their data, this really isn’t true. Figures 1 and 3 show site M10-231v as an ‘Eemian’ site with dates ranging from 23,900 to 44,300 years. But ages at two nearby sites, M10-B226v and M10-223v, whose ages are shown as 2-3,000 and 4-5,000 years old, are higher than the site with old dates (Figure 4).
Figure 3. Site M10-231v, dated at 23.9 ka to 44.3 ka at an altitude of 1395m (4577 ft) and sites M10-226v at 1438m (4718 ft.) and M10-223v at 1405mm (4609 ft). (Google Earth image)
Figure 4. Elevations of sites M10-223v (2-3,000 yrs) and M10-226v (4-5,000 yrs) are higher than the ‘Eemian’ site >47,000 years.
This totally destroys their argument for no temperature as warm as the present since the Eemian Interglacial. All they have shown is that melting of the ice caps on Baffin Island wasn’t complete during the Holocene and recent warming has continued the melting.
Comparison of Miller et al. conclusons with other Arctic data.
The conclusions of the Miller et al. paper are that “there has been no intervening century during which summer warmth exceeded that of the last ~100 years” and “average summer temperatures of the last ~100 years are now higher than any century in more than 44,000 years.” How do these conclusions stack up against other data concerning past Arctic temperatures? Let’s compare them with recent recorded temperatures in Greenland and with past temperatures derived from Greenland ice core data.
Comparison with recent Arctic temperatures
Summer temperature records at Clyde, north of the sample sites, show no warming from 1940 to 2009 (Fig. 5). How is it that “temperatures of the past century must have exceeded those of any century in more than 44 ka” when temperature records clearly show no warming over the past 70 years? This makes no sense at all!
Figure 5. Summer temperatures at Clyde, north of sample sites.
Temperature records from Greenland and other Arctic areas also show no unusual warming. Yes, temperatures have warmed and cooled, but the 1930s were consistently warmer than the more recent warming from 1978 to 1998 (Figs. 6, 7, 8, 9).
Figure 6. Temperatures in Angmagssalk, Figure 7. Arctic temperatures (70-90 N latitude, -180
Greenland were warmer in the 1930s (before to 180 longitude) between 1880 and 2000 show that
CO2 began to rise sharply) than during recent the 1930s and early 1940s were warmer than recent
warming from 1978-1998. warming (1978-1998). (Modified from Chylek et al.
2004, 2006)
Figure 8. Arctic temperatures in Iceland, Norway, Figure 9. Average Arctic annual temperatures were
and Russia from 1890 to 2010 show that the 1930s warmer in the 1930s (before CO2 began to rise
and early 1940s were warmer than recent warming sharply) than during recent warming from 1978-
from 1978-1998. 1998.
Comparison with temperatures recorded in Greenland GISP2 ice cores
Figure 10 shows that virtually all of the period from 1500 years ago to 5000 years ago was warmer than modern temperatures. This data is directly contrary to the Miller et al. conclusion that “average summer temperatures of the last ~100 years are now higher than any century in more than 44,000 years.”
Figure 10. Temperatures during the Medieval Warm Period, the Roman Warm Period, and the rest of the time back to 5000 years ago were all warmer than the past century, directly contradicting the conclusion of Miller et al.
Looking still farther back in time, about 90% of the past 10,000 years were warmer than temperatures of the past century (Fig. 11). Thus, the Miller et al. conclusion that “temperatures of the past century must have exceeded those of any century in more than 44 ka” cannot be true.
Figure 10. Temperatures during ~90% of the past 10,000 years were warmer than the past century. (Modified from Cuffy and Clow, 1997; Alley,2000).
Temperatures during the late Pleistocene fluctuated dramatically, rising 20°F in a single century at least three times. These rates of warming were far greater (~20 times greater) than warming during the past century. Thus, the Miller et al. conclusions cannot be valid.
Conclusions
From the foregoing data and analyses, what is abundantly clear is that the Miller et al. paper is so badly flawed with unwarranted assumptions, poorly thought out assertions, and astonishingly bad logic that their conclusion “temperatures of the past century must have exceeded those of any century in more than 44 ka” cannot be considered valid. How could reputable scientists come to such incorrect conclusions? Perhaps the last sentence in their conclusions section gives us a clue: “anthropogenic emissions of greenhouse gases have now resulted in unprecedented recent summer warmth that is well outside the range of that attributable to natural climate variability.” Even if the conclusions in the paper were correct, they wouldn’t prove anything about CO2 as the cause of climatic warming, so this statement suggests that the real purpose of the paper was to push CO2 at the expense of objective science.
” One wonders how this bad logic got past peer review. ”
This one doesn’t wonder. The process has been corrupted for political reasons and financial gain.
Nice post, Don.
“although glaciers are frequently associated with deep and widespread erosion, small, cold-based ice caps that mantle relatively flat terrain typically advance by lateral accretion rather than by basal flow, and are thus capable of preserving even the most delicate features of the landscape……”
“Miller et al. assume that the ice caps are cold-based (i.e., basal ice is frozen to the ground below) … However, deep fiords and ice-scoured scoured bedrock in the area attest to active subglacial erosion (i.e., basal sliding rather than frozen to the ground)…. where the sample sites are located, are above freezing during June, July, August, and September. Thus, the Miller et al. conclusion that the small ice caps in this study are frozen to their base is highly questionable and most like not true.”
So you live in Washington, you can drive to many glaciers that are shrinking and leaving cold bare rock behind. Do you see “delicate features of the landscape” ? I never have, not in those old glacial troughs (and I been in more than a few lately both in your state and in MT). And if you did find something plant like, I wonder if you would expect it to be so old that you couldn’t use C14 dating? Maybe you could explain how that could happen, because I can’t imagine. The logic that the plants hadn’t moved and have never been uncovered for some 50K years or longer, seems inescapable.
And, BTW, permafrost doesn’t thaw in the summer if it’s covered with snow, no matter how warm the summer temps get.
This isn’t the end of the nonsense. They tell us the moss is quickly destroyed when it thaws, which is why they know it hadn’t thawed before. Okay, but what if we had done their survey 50 ya, 100ya, during the LIA, the MWP, the dark ages? Would we have found freshly exposed moss then? By logical deduction from their own claims, we cannot now know what would have been found. Perhaps old moss would have been found at all these times? Or at least the warmer ones? And that would prove that the recent few 1,000 years’ warming had nothing to do with AGW. Since by their own claims the disproving experiment cannot be done, their uniqueness claims are not scientific, just guesswork.
Ron House says: “Okay, but what if we had done their survey 50 ya, 100ya, during the LIA, the MWP, the dark ages? Would we have found freshly exposed moss then?
perhaps. but it wouldn’t be the moss was found in this study …that moss was buried then.
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The last line says it all: “the real purpose of the paper was to push CO2 at the expense of objective science”
The emerging ice-covered agricultural traces of Vikings flatly disprove that recent temperatures are even close to past warm and benign times.
“anthropogenic emissions of greenhouse gases have now resulted in unprecedented recent summer warmth that is well outside the range of that attributable to natural climate variability.”
If they’re going to claim that the Arctic warming (or anywhere else) post-1960s is mostly anthropogenic, then the warming c1915 – c1940 must mostly be due to something else.
That’s obvious: http://www.earth-policy.org/images/uploads/graphs_tables/Global_Carbon_Dioxide_Emissions_from_Fossil_Fuel_Burning,_1751-2009.GIF
This is a perfect example of politically driven pseudo-science: to jump from a single small, flawed study to a political concluding message, totally ignoring the existing body of scientific data on the subject. The paper is aimed straight at the media and politicians, over the heads of the scientific community.
Mann, Marcott, Miller … who will be the next mendacious machiavellian?
I would fully endorse point 2 in the article. It only needs to be ‘warm enough’ to continue melting of ice which in the past may have melted more quickly by higher temperatures than today. According to CRU the two warmest consecutive decades were the 1930’s and 1940’s.
tonyb
There is so much wrong with Miller’s (thankfully no relation) that it beggars belief.
For someone to assert that some moss survived in situ at a relatively high altitude in northern Baffin Land through the last ice age of ~120,000 years, is plain ridiculous.
Glacial ice is an incredibly effective abrasive, as can be seen by the deep scratches it has left behind on rocky outcrops – nothing survives the advance of the glaciers.
On the other hand if there were no glaciers, the process of erosion by wind, water and seasonal ice over a period of 120,000 years would have destroyed everything.
If the samples are real, then they must have originally come from a long way away. A good example of this is the hunt for diamonds 20 years ago in northern Canada when geologists followed trails of G10 garnets many hundreds of kilometres back to the original source kimberlites.
But it is all about the evil gas CO2 and maintaining access to the bottomless troughs of grant cash to ‘research’ this non-problem.
We do not yet have an ice-free Arctic. Yet HERE are 4 paper abstracts which find evidence for an ice-free Arctic during the Holocene. Yet we are to believe that the Arctic is warmer now than during the Holocene Climate Optimum. Here are More criticisms of Miller.
Here is something else worth considering bearing in mind Miller’s conclusions about moss on Baffin Island.
The northernmost part of the Eurasian mainland is the Taymyr Peninsula. Now look at the tree-line during the Holocene Climate Optimum compared to today.
I can see it is time for Miller et al to do finger ear and vocal exercise number 1.
1 Put the index finger from each hand in your ear.
2 Open mouth wide and sing LA-La, LA-La.
3 Keep this up till those with hard and difficult questions get board and go away.
4 Sit back and know that you are way smarter than anyone else in the room.
James Bull
Pal reviewed science at its finest.
I updated the Clyde, Nunavut graph (here), but I don’t know if I did it right. It looks different from the graph used in this blog post, with 2012 breaking the record for warmest summer since 1946.
Data found at Environment Canada.
“Thus, the Miller et al. conclusions that “temperatures of the past century must have exceeded those of any century in more than 44 ka” and “there has been no intervening century during which warmth exceeded that of the last 100 years” are illogical and badly flawed. One wonders how this bad logic got past peer review. ”
The anals [sic] of climatology are now so full of this BS non-science that it’s no longer worth counting. Science is corrupt and the reviewers are as biased as the authors that put this kind of politically motivated garbage up to be published.
Good article none the less.
Do those pseudoscientists never study backgroundsliterature?
What about Ötztal-man from 5000 years ago
What about the path through Schnidejoch-ice where 300pieces from younger stone age, bronze age, roman period, and middle age was found. And what about scandes treeline 600 m higher during climate optimum than during Little ice age. Nowadays appr. 100 m higher than LIAS.
Oh those propagandists!
Neven: Data found at Environment Canada.
It would be better if Don provided sources for his data too, nullus in verbum.
However, a clue as to why the data you got do not look the same comes from reading the presentation of the data:
Environment Canada:
===
Adjusted and Homogenized Canadian Climate Data (AHCCD)
These data are not the official Meteorological Service of Canada in situ station records and therefore should not be used for legal purposes. The official records can be obtained at the National Climate Data and Information Archive.
Users are strongly cautioned to determine the data suitability for their application. They should also be aware that ongoing research on adjustment techniques may result in future revisions of the datasets. The datasets are updated annually with the most recent data.
===
And in Baffin Bay, researchers have found that
Presently, the Baffin Bay southern sea-ice boundary extends from Disko Island to the southwest, towards Canada. This would imply that prior to AD 1250 this boundary was more northerly and gradually moved towards the vicinity of the core site until after AD 1500 (Little Ice Age), when it was positioned south of the core site.
http://notalotofpeopleknowthat.wordpress.com/2012/01/21/little-ice-age-coldest-period-in-the-last-7000-years-in-greenland/
OK, so instead of us all banging our dustbins here – who’s going to write a rebuttal and present it to the Journal Editor??
Oke nice one. Again still the same problem as always(whit wings for a better fit). They use there fantasy world temperature data and we all know thats plain wrong. This result cane only be produces if you use wrong data and wrong data can only Giff wrong results.
So in order to make it work someone must put the good data in. But what result will we get? Yes a cooler or even much cooler result but hey the globe is warming so thats impossible.
And there you have the 2 problems. They refuse to admit the globe is cooling so the result must always be warmer then the past to proof the globe is warming at least on paper in there fantasy’s.
Now they cant go back to real life so they have to work whit a fantasy. The only way to stop this is to show how the real world works.
Why is the temperature dropping and how much and why are the low temperatures in fact the result of global cooling and not warming. But more important is the temperature, what is the reality. How hight or low is the real global temperature.
It is all true, and a very good article. But no-one who matters is listening, and the Royal Society and American Physical Society, etc. are not going to change their minds about CAGW. I hope Marcia Wyatt reads this.
The bad logic and baseless assumptions of this paper are astounding. The fact that such rubbish can be published in a “scientific” journal tells us much about the state of “science” in the modern age.
Warming has been global in the Holocene, and stuff is still coming out from under the ice worldwide for instance:
http://www.amjbot.org/content/97/9/1579.full
The most obvious conclusion is that moss grew here 41K-47K years therefore it was warmer at the time than today.
http://s23.postimg.org/40862648r/5_sample_dates_Miller2013.jpg
But the isotope data indicates the planet was still in the grips of the ice age at the time, and while there are certainly many upspikes in temperature in the last ice age (and a large one at 50K years ago), Baffin Island was probably not warm enough for moss to grow here and the Laurentide ice sheet was either at these summits or very close.
So the more likely explanation is that Carbon14 dating becomes unreliable as one approaches 50K years and therefore the moss probably came from the Eemian interglacial 130K-115K years ago which certainly appears to be warm enough to allow moss to grow on these isolated mountains (as much as 4.0C warmer at this location).
But …
CO2 @ 41K-47K years ago –> 188-210 ppm
CO2 @ 130K-115K years ago –> 259-287 ppm
So what part does CO2 play in this again?
Regarding the moss, if you believe the age dates you have to believe that the moss was covered for that period of time. Moss does not die, move several kilometers and then replant itself. If Miller merely collected moss trapped in ice then his entire research is worthless.
Miller acknowledges his work does not mean the whole Arctic is warmer, just the area of Baffin Island he studied. It is well known the Arctic does not warm uniformly. Miller’s next step is to see if this unprecedented warming is throughout the Arctic.
Miller states the study area could not have held more than 70 m of ice because of the changes in elevation (which would make much more ice unstable). That seems plausible but also highly unproveable.
You can have older moss at lower elevations depending on how an area heats up during the summer. I hiked at Blue Mountain (Ontario) one summer and was surprised by all the unmelted ice, especially in areas shielded from direct sunlight.
Not sure if it was mentioned in Don’s great piece here (JC also has a great guest post on this to which Miller replied) but the ice has been known to be receding since the last ice age. A few pockets of ice only now melted does not mean anything about modern temperatures compared to older ones.
Very good article.
Among many other indicators that the Holocene Climate Optimum was warmer than now, Velichko et al. 1999 noted that
“Vegetation which existed in Northern Eurasia … 5.5–6 ka BP [Before Present] accumulated” “292.1 Gt of phytomass,” a value “120%” of now.
Lutaenko et al. 1993 noted warmer temperatures during Holocene Climate Optimum are implied by how “the shift of the southern boundary of the Pacific boreal region was 700–800 km to the north compared to its present-day position (based on bivalve mollusks).”
One could go on for quite a while with more examples, for region after region and for the global average, like Huang et al. 1997 was explicit on how the “early to mid-Holocene appears as a relatively long warm interval” above present-day temperatures in their “reconstruction of a global average ground surface temperature history.”
The Modern Warm Period is nothing exceptional (unsurprisingly so when the patterns in recent historical sea level rise rate, humidity, cloud cover, and temperature in http://img176.imagevenue.com/img.php?image=81829_expanded_overview_122_424lo.jpg all fit predominately natural climate change as illustrated).
As concerns so much of what passes for AGW research, this looks like yet another study whose main point is find a way to rationalize the CO2 obsession of the AGW movement.
Pippen Kool says:November 2, 2013 at 10:32 pm
[…]
And, BTW, permafrost doesn’t thaw in the summer if it’s covered with snow, no matter how warm the summer temps get.
That’s right it can’t melt if it stays below freezing. Brilliant!
I oftentimes like to point out to those who believe it is far warmer now days, …. than at any time in the past, …… the fact that it was the Roman Warm Period …. that did the Romans in, to wit:
Hannibal lucked out when he decided to march his army and herd of war elephants across the Alps to attack the Romans in 218 BC because there surely could not have been as much or as many glaciers or heavy snowpack blocking his route since documented history proves he accomplished that feat which I don’t think could be repeated today. http://en.wikipedia.org/wiki/Hannibal's_Crossing_of_the_Alps
Could someone help me with the graphs? Figure 10 or 11 ( confusing which one) which shows the last 10,000 years of Temperatures seem to have the C Degrees on the right inverted. How can the Little Ice Age be warmer than the Minoan Warm Period. Am I not understanding what it shows or are the Degrees upside down. Anyone want to help me?
This work by Dr. Easterbrook is nothing less than a metaphorical public flogging of Miller, et al.
Birdieshooter says:
November 3, 2013 at 6:54 am
“…or are the Degrees upside down. ”
____________________
Yes, they are. (I’m sure you’ve seen that, by now.)
Oops- hit the send button too quickly. The degrees scale is negative, i.e. the further down the Y- axis, the colder temp is shown. That isn’t really upside down, but just showing the scale as below zero on the Y- axis.
Thanks Alan. Makes all the sense in the world now. My eyes (or brain) never picked up on the negative signs. Not used to thinking in those cold extremes.
Here is someone who says that soot can expose parts of the ice cap on Baffin Island. They say it was part of their research. They show photos too. Was Millar peering into one of these areas opened up by soot? We may never know, unless he tells us (the truth). 😉
Further to my last comment here is a close up of the soot puddles on the Baffin Island ice cap.
http://www.acespace.org/blog/wp-content/uploads/2010/12/Baffin-icecap.jpg
From
http://www.acespace.org/blog/2010/12/black-carbon-the-dirty-and-doubly-evil-sidekick-of-co2/
Easterbrook apparently is on an ideological mission – not a science-based one:
If subglacial erosion leaves scours in bedrock due to basal sliding, then basal sliding must *NOT* have occurred, else the fragile mosses would have been scoured into dust – much less remained rooted. So Miller et al’s assumption is obviously correct and Easterbrook is just plain wrong. This is such a simple counter-factual that is there really any need to read more of Easterbrook?
Figure 10 doesn’t (?) show the Minoan Warm Period, does it? Shows a cold period at 2500 BC.
So Greenland – and Greece – show the regionality of “global” temperatures.
Once you have one regionality established, you have to concede that whatevery study you do MAY only relate to your study area.
I’m a geologist. I’m not rich. If one region of my mapping were “global” even within a 100 km radius, I would be rich.
Reality trumps models, especially in the wallet.
Thus, the Miller et al. conclusions that “temperatures of the past century must have exceeded those of any century in more than 44 ka” and “there has been no intervening century during which warmth exceeded that of the last 100 years” are illogical and badly flawed. One wonders how this bad logic got past peer review.
==================
Agreed. The flaw in the logic is so obvious that is wouldn’t get past your average grade school pupil. Ask any child over the age of 6 to solve this problem. Does a block of ice that was put out in the morning and is still melting in the evening, does this mean that the temperatures in the evening are higher than they were at any time during the day?
9 times out of 10 the child will tell you it simply means it was a large block of ice. Yet we have supposedly trained scientists that can’t figure this out. This says a lot about the state of peer review in Climate Science, that such a bone head error could have been published.
Miller makes the same mistake as in this 2001 paper:
http://www.co2science.org/articles/V4/N32/C1.php
Warming in Baffin Island occurs when there is cooling in the temperate zone, due to negative NAO conditions, which in a trend has to mean a global cooling phase.
http://wattsupwiththat.com/2013/08/23/the-medieval-warm-period-in-the-arctic/#comment-1398577
(this, and the following comments of mine on the thread)
Kevin O’Neill says:
November 3, 2013 at 9:24 am
Easterbrook apparently is on an ideological mission – not a science-based one:
============
it would appear the pot is calling the kettle black.
ferd b,
It’s just another case of alarmist projection.
Steve from Rockwood says:
November 3, 2013 at 5:58 am
Miller’s next step is to see if this unprecedented warming is throughout the Arctic.
============
No, his next step is to take a course in logic, so he can understand that all he has demonstrated is that the block of ice was too big to melt completely when temperatures rose during the interglacial. That over the past 10,000 years that this block of ice has been melting there have been many warm periods, some much warmer than present, and as this block of ice continues to melt it will uncover more and more items that were buried 100,000 years ago.
Steve from Rockwood says:
Not sure if it was mentioned in Don’s great piece here (JC also has a great guest post on this to which Miller replied) but the ice has been known to be receding since the last ice age. A few pockets of ice only now melted does not mean anything about modern temperatures compared to older ones.
=====================================
JC?? What is that? I would be interested in reading that, got a link?
It is quite clear that the Arctic was warmer 5000 to 6000 years ago than it is today.
http://climatesanity.wordpress.com/2008/10/15/dont-panic-the-arctic-has-survived-warmer-temperatures-in-the-past/
TomR,Worc,MA,USA says:
November 3, 2013 at 10:11 am
JC?? What is that? I would be interested in reading that, got a link?
_____
http://judithcurry.com/2013/10/29/unprecedented-arctic-warming-part-ii/
dbstealey says:
November 3, 2013 at 9:55 am
It’s just another case of alarmist projection.
=============
Agreed, it is inconceivable that Miller et al, as well as the reviewers are not aware of the flaws in their logic. It is also inconceivable that they are not aware of the large body of evidence showing that arctic temps 10,000 years ago were warmer than now. Which strongly suggests this was not an innocent mistake.
Even if you accept that the ice hasn’t moved in the slightest for tens of thousands of years, which in itself is not believable because ice slowly deforms under load, and the weight of ice above will cause the base to spread as it tries to avoid the load. And this action will scour.
Even if, you still have the problem of temperature. The fact that a block of ice is smaller today than it was 40,000 years ago tells you nothing about temperature in the past, except that 40,000+ years ago temperatures in the region must have been above freezing.
You can’t even conclude that temperatures 40,000+ years ago were warmer than today, except if moss won’t grow in the region today. The presence or lack of ice however does not tell you how much above freezing temperatures might have been, because ice melts not as a function of temperature, but as the integral of temperature over time.
You can have very high temperatures, and the ice won’t melt completely so long as the conditions only last for a relatively short period of time. Antarctica or Greenland could be as warm as the tropics and it would still take thousands of years for their ice sheets to melt completely.
ronald says:
November 3, 2013 at 4:10 am
You know I get the jest of what you are saying but WOW proof read before you hit send ;>)
I really think that a lot of these concerns have been answered pretty effectively. See climateaudit and Judith Curry’s site, where Richard Telford and Giff Miller himself answered a lot of questions. Some of the ones I saw: the mosses he found were rooted, and thus had not been moved. If a glacier had been there or passed over them, they would have been crushed completely – that implies that this area wasn’t under a glacier during the time in question. If it wasn’t under a glacier, the seventy meter thickness limit returns, and is very important: it means that more than a century or so of higher temperatures would have removed the ice cap completely.
I’m not saying that the study has been proven valid, just that reading a blog post like this doesn’t prove much. Most of us are not competent to judge these things. I do think that if Dr. Easterbrook has good points to make, it would make sense to post some of them on those blogs (or Richard Telford’s, or Jim Bouldin’s) where the discussion has taken place so far, and some of us have learned things. Why start at the beginning again? (I’d make the same point to Tamino, or Michael Mann, who like to “prove” their points at websites under their own control, where they can control what responses are allowed to appear. Go discuss directly with the other side in the argument.)
lorne50 says:
November 3, 2013 at 10:50 am
=================
Did you mean gist ??
Couldn’t resist 🙂
Kevin O’Neill says:
I think you’re not comprehending what Easterbook is claiming, here. His argument is that the Laurentide Ice Sheet might have overtopped these ice caps, making them far deeper than 70 meters. The glacial erosion that he’s talking about is that of the larger surrounding glacier, NOTof these ensconced caps, which lie in a frozen cirques and would not necessary move. The erosion of ice floes down the valleys surrounding these cirques is very obvious, and this means the LIS was probably active in this area. So IF these mossy ice caps were covered by a larger glacier (likely), then the melt of the ice sheet over the mosses would be much longer than 44k years, and the heating needed to melt it more extensive.
Besides lengthening the period of the melt, what do you think of the logical critique of Miller’s silly assumption that the day a glacier retreats to expose some previously covered and undamaged flora must therefore be the warmest period since the flora was covered in the first place? If I take an frozen ice cube tray out of the freezer, leave it on the counter in midafternoon, then the last bit of ice melts at 9:00 pm, does that prove that It’s warmer at 9:00 pm than it was at 4:00 pm?
Forget logic, look at the treelines during the Holocene. Many are further north covering a greater geographic area than Miller et. al.
Correction:
It’s not called “Clyde” … it’s Clyde River … maybe they omitted the river part for a reason 🙂
Did Miller omit to supply any photographs of cute animals drowning under rising sea levels to back his conclusions up?
RE the 70m limit on icecap thickness…would not further accumulation then form a dynamic overriding glacier, which could achieve much greater thickness while flowing over into the lower valleys?
Jaems Strom asks: “JC?? What is that? I would be interested in reading that, got a link?”
JC is Climatologist Judith Curry, her site is here http://judithcurry.com/
Kevin O’Neill’s criticism of Easterbrook is an obvious display of projection. He should reply to the comments of TonyB and Mickey Reno, if he wants to be taken seriously, with some solid science.
Regular readers of WUWT would know that TonyB would answer with a sensible contribution, but it was nice to see Mickey Reno chip in with a suitable rebuttal also.
No. Miller deduces that the ice caps are cold based from the fact that moss is found in-situ.
No, but Miller does present a scenario that explains his conclusion that it is necessarily true. Easterbrook does not address that explanation.
Yes, it does. Here, Easterbrook commits the warmists’ current favorite fallacy – conflating “warm” with “warming”. They are fond of making the asinine claim that the globe must still be warming, because it is still warm. Easterbrook inverts that, claiming Baffin Island cannot be warm, because it is not warming. Same crappy reasoning, different spin.
Miller’s paper is chock full of sketchy (and mostly unstated) assumptions, and examples of faulty reasoning. These are not among them. Easterbrook hits hard on some of Miller’s weaknesses, but others remain unexamined. Among those:
1) When a few percent of lab results are “out there”, suggest startling conclusions, and require boatloads of assumptions and extraordinary reasoning to explain, parsimony suggests that perhaps the lab results are wrong. Carbon dating is not an error free process. When a few percent of your samples show dates 20 times older than the rest, step one would be to take verification samples, to see if you can replicate your results. What is behind the rush to (extreme, and probably poor) judgement? The implications of “the Pause”?
2) The current simultaneous exposure of very young paleo-mosses and (allegedly) very old paleo-mosses is not accounted for by Miller in the context of his assertion that temperature determine glacier extent. By what mechanism is this supposed to have occurred, and what are the implications of that explanation with respect to Miller’s claim that unprecedented current temperatures are the ONLY way the older mosses could be exposed now? Huge hole. Many trucks running abreast.
3) At the few sites that showed the limited-out C14 aging, it was not mostly mosses, but lichens that were found. What explanations are there for this, and what are the implications for the Miller claims?
4) The claim of max 70m ice cap thickness does not follow from the math that Miller used to calculate it. That comes to 50m, which is the figure that Miller has used in previous presentations on this topic. Why 70 now? And when was it most recently at this alleged maximum thickness? And what was the thickness of this cap in 1913? Inconsistencies and unaddressed assumptions abound. How many others are there? Does this cap meet the assumptions of Nye’s Ideal Circular Ice Cap? Has it always for the last 120ky?
5) Where did this current melt rate (0.5m/y) come from? The assertion is that snowline is determined solely by temperature. The same is assumed for melt rate. How is that assumption supported? How is circularity in this line of reasoning avoided?
@Samuel C Cogar –
And Hannibal’s traverse of the Alps was only at the beginning of the warming – the Roman Warm Period really didn’t reach full force for another 100 years.
The vicintiy of the LIS cooled that location during the early/mid holocene irrepective if it was part of the LIS and the accumulation limited to 70 m or not. That location is then no indication for global temperatures.
Black soot is the elephant in the Arctic (after AMO and the LIS for that Baffin Island location).
The IPCC has global forcing value of 0.1 W/m2 for black soot on snow/ice.
Hansen 2004 wrote that black soot is 3 times more efficient in warming than an equal CO2 forcing. -> 0.3W/m2
Almost all soot is in the northern hemisphere another factor of 2. ->0.6W/m
Only a small fraction of the northern hemisphere is covered by ice/snow. That leaves a forcing of several W/m2 for the ice covered regions.
(plus 0.7 W/m2 radiative forcing of black soot in the atmosphere)
They got their headline.
Here’s what LiveScience reported and was the October 24 headline on Yahoo:
Arctic Temperatures Highest in at Least 44,000 Years
Interestingly this came out at the END of what the Danish Meteorological Institute tracked as the shortest Summer above freezing and coldest on record.
Well timed. Well placed.
Miller claims that the location in question could have had a maximum of 50 or 70 meters of snow coverage (not glacial coverage). Miller claims that the snow coverage (now melted) would have melted long ago if the temperatures then had been comparable to today’s for as long as a century or so.
Let’s assume, just for argument that he is correct; fifty meters of snow melt in 100 years, in other words,average net snow melting of half meter per year of warmth. This is not unreasonable. Or rather, it is not unreasonable if we know with some certainty that winter snowfall is so limited that we get that net half meter melt. So… what was the snowfall at Baffin Island during the last 10,000 years or so? Is there any reason to think that snowfall there over the last ten millennia has consistently been such that current temperatures would melt all of the winter accumulation plus another half meter? Heck, I’ve even read some CAGW enthusiasts who swear that warmer temperatures mean MORE snow. Maybe it was warmer 5,000 years ago but the snow was heavier and therefore did not get that net half meter melt.
I would be very surprised if we have accurate data on snowfall for the last ten thousand years at Baffin Island.
Mickey Reno says:
November 3, 2013 at 11:22 am
“If I take an frozen ice cube tray out of the freezer, leave it on the counter in midafternoon, then the last bit of ice melts at 9:00 pm, does that prove that It’s warmer at 9:00 pm than it was at 4:00 pm?”
__________________________
Thank you. That simple analogy negates the premise of Miller, et al.
Not discounting the ice cube tray experiment, if your moss is rooted in the earth, your theory is rooted in science. Climate science seems to have so many great observations and yet only ever one conclusion. That on its own is reason to doubt the consensus.
Can I point out Otzi the Iceman? He didn’t crawl under a glacier to die, yet he was found where he died – under a glacier near the top of a mountain. His body was protected from the ice movement by a rock ledge.
Pippen Kool says:
Tell us why you think that has any relevance whatever to my argument. AFAICT it’s a complete non-sequitur as irrelevant as saying “Perhaps. but there are roses on sale at my local florist.”
tommoriarty says:
November 3, 2013 at 10:17 am
It is quite clear that the Arctic was warmer 5000 to 6000 years ago than it is today.
http://climatesanity.wordpress.com/2008/10/15/dont-panic-the-arctic-has-survived-warmer-temperatures-in-the-past/
===================================================
It is also quite clear that Greenland was cold between 2700BC and 2500BC when there were major maximum’s in temperate zone temperatures that enabled the biggest expansion of all the classic great civilisations, e.g. Egyptian, Harrapan, Chinese, Minoan, Peruvian, European Neolithic:
http://smpro.ca/crunch/GISP2Civil.png
And then there’s that sudden cooling around 1200 BC that collapsed many cultures:
https://www.google.co.uk/?gws_rd=cr#q=1200+BC+climate
in Greenland it was the warmest:
http://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Greenland_Gisp2_Temperature.svg/800px-Greenland_Gisp2_Temperature.svg.png
Oops!
http://www.glyfac.buffalo.edu/Faculty/briner/buf/pubs/Axford_et_al_2013.pdf
Meanwhile, down in the Antarctic…..
I complained to the BBC that they had no coverage of the huge extend of Antarctic Sea Ice this year. This, was their reply:
.
Reference CAS-2376609-TJ8YC5
Thank you for contacting us regarding BBC News.
I understand you feel that our coverage of climate change issues is biased and that it has failed to address recent data that shows Antarctic ice to be at record levels.
Impartiality is the cornerstone of all our output and we ensure all our correspondents and production teams are aware of this to help us deliver fair and balanced coverage for all the stories we report.
Senior editorial staff, the Executive Committee and the BBC Trust keep a close watch on programmes to ensure that standards of impartiality are maintained.
Climate change and global warming are amongst the most high profile news stories of recent years and while we are fully committed to balanced and impartial coverage of the issue, the overwhelming scientific opinion is that human activity is increasing the rate at which earth’s global temperature is rising by.
As a public service broadcaster we have an obligation to reflect this broad scientific agreement on climate change and we reflect this accordingly; however, we do aim to ensure that we also offer time to the dissenting voices.
While it might not always be possible to reflect all opinions in one programme we charge our editors with ensuring that all relevant voices are heard over a reasonable period of time across our programming output, and this has included our main news broadcasts and flagship programmes such as ‘Newsnight’.
Nevertheless, I would like to assure you that I have registered your concerns on our audience log. This is a daily report of audience feedback that is made available to many BBC staff, including members of the BBC Executive Board, programme makers, channel controllers and other senior managers.
The audience logs are seen as important documents that can help shape decisions about future programming and content.
Thank you once again for getting in touch.
Kind Regards
Terry Hughes
BBC Complaints
.
Greenland is so called as from around 850AD to 1350AD it was largely covered in grass. The Vikings lived there for around 500 years.
Not possible if it was colder than today.
This report is another example of desperation from desperate people.
There are very few rolls of the dice left before the nonsense is finally swept away and it will come when the green taxes are dropped and a politician has to stand in front of Parliament and sit in a BBC studio and explain things.
“anthropogenic emissions of greenhouse gases have now resulted in unprecedented recent summer warmth that is well outside the range of that attributable to natural climate variability.”
One tiny wee flaw, nobody knows what “natural climate variability” is! So how one can pronounce thats some apparent arming is outside it, well or otherwise, is a mystery!
Anyway we beat the Australians at Twickers on Saturday, must be AGW!
The same Mr Miller was co-author on 2001 paper regarding Baffin temperatures:
“Little Ice Age recorded in summer temperature reconstruction from vared sediments of Donard Lake, Baffin Island, Canada”
http://link.springer.com/article/10.1023/A:1011181301514
https://notendur.hi.is/~oi/AG-326%202006%20readings/Anthropocene/Moore_JOPL2001.pdf
Back then the warmest period in last 1200 years was between 1200-1375 AD. 1960s was one of the coldest periods. In general that 2001 paper is in total conflict with the new one.
Chad Wozniak says:
November 3, 2013 at 2:38 pm
@Samuel C Cogar –
And Hannibal’s traverse of the Alps was only at the beginning of the warming – the Roman Warm Period really didn’t reach full force for another 100 years.
——————-
You got that right, Chad.
And the silliness of the proponents of CAGW and the IPCC have been touting their claim about the current unprecedented melting of the Alpine Glaciers in an attempt to justify their “junk science” claims about “greenhouse” gases.
MAK says:
“The same Mr Miller was co-author on 2001 paper regarding Baffin temperatures…
Back then the warmest period in last 1200 years was between 1200-1375 AD.”
A colder period in the temperate zone:
http://wattsupwiththat.com/2013/11/02/miller-et-al-s-unprecedented-recent-summer-warmth-in-arctic-canada-bad-assumptions-poor-logic-and-contrary-to-other-evidence-of-arctic-temperatures/#comment-1465135
Assertions and assumptions by Miller et al.
[2] Miller et al. claim that recent exposure of moss by melting ice proves that modern temperatures at the site were as high or higher than at any time since the moss was covered by ice and that therefore present temperatures have not been exceeded in 120,000 years. ?
————————–
If the above is actually what Millel el al claims then his claim is pathetically illogical simply because the current melting “act” that revealed those moss plants does not prove that present temperatures have exceeded the temperatures at the time said moss plants were sexually reproducing and growing.
Mosses (Bryophytes) are persnickety propagators and/or reproducers and unless the temperature and moisture are just so-so they will not grow, to wit:
—————
“In dioicous mosses, male and female sex organs are borne on different gametophyte plants. In monoicous (also called autoicous) mosses, both are borne on the same plant. In the presence of water, sperm from the antheridia swim to the archegonia and fertilisation occurs, leading to the production of a diploid sporophyte. The sperm of mosses is biflagellate, i.e. they have two flagellae that aid in propulsion. Since the sperm must swim to the archegonium, fertilisation cannot occur without water. After fertilisation, the immature sporophyte pushes its way out of the archegonial venter. It takes about a quarter to half a year for the sporophyte to mature.
Wherever they occur, mosses require high levels of moisture to survive because of the lack of a vascular system, and the need for liquid water to complete fertilisation. Many mosses can survive desiccation, sometimes for months, returning to life within a few hours of rehydration.” http://en.wikipedia.org/wiki/Moss
========================
Thus, the question is, are current climatic conditions (temperatures and moisture) in the Baffin Island area conducive to/for the growth and reproduction of mosses?
HA, I again messed up when entering that “editing” text. Sorry bout that.
MAK says:
The same Mr Miller was co-author on 2001 paper regarding Baffin temperatures:
“Little Ice Age recorded in summer temperature reconstruction from vared sediments of Donard Lake, Baffin Island, Canada”
http://link.springer.com/article/10.1023/A:1011181301514
https://notendur.hi.is/~oi/AG-326%202006%20readings/Anthropocene/Moore_JOPL2001.pdf
Back then the warmest period in last 1200 years was between 1200-1375 AD. 1960s was one of the coldest periods. In general that 2001 paper is in total conflict with the new one.
GOOD OBSERVATION–THEIR TEMP CURVE SHOWS THE MEDIEVAL WARM PERIOD WARMER THAN RECENT, YET MILLER SEEMS TO HAVE CONVENIENTLY FORGOTTEN HIS OWN EARLIER PAPER, WHICH CONTRADICTS THE PRESENT PAPER.
Don Easterbrook says:
“THEIR TEMP CURVE SHOWS THE MEDIEVAL WARM PERIOD WARMER THAN RECENT”
Which means that there were much colder conditions in the mid latitudes from 1195, and exactly at the rapid cooling in Baffin Island in 1375, there were very high temperatures at least in the UK. The same for the warm 1950/60’s in Baffin, it was colder then in the temperate zone then:
“The cold period was followed by large and rapid warming in the 1950s leading to a maximum around 1960 AD and cooler conditions toward the present.”
https://notendur.hi.is/~oi/AG-326%202006%20readings/Anthropocene/Moore_JOPL2001.pdf
That’s the negative NAO conditions, particularly from the late 1950’s:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/month_nao_index.shtml
Warming in Baffin Island means cooling in the mid latitudes.
Dr. Easterbrook’s and Dr. Wyatt’s critique of the Miller et. al. paper is what peer review is all about.
Nice work Don. To conclude that recent temperatures have been the warmest over some period Miller et al. would have to show that the RATE of recent melting was the highest over that period (controlling for the area of non-seasonal ice that is available for melting). Instead they looked at the level of ice melt. They are looking at the wrong stupid derivative.
Interestingly, this is the same “mistake” that warmist “scientists” make in order to avoid the evidence that the 20th century’s high level of solar activity was responsible for 20th century warming. They acknowledge the numerous findings of a high degree of correlation between solar-magnetic activity and climate but always add that the sun couldn’t have caused late 20th century warming because solar activity was not increasing over this period (as if it is the CHANGE in the level of solar activity, rather than the level of solar activity, that would cause warming).
I have been collecting such statements for several years. Here is a list of 18 from various individual warmist scientists, plus several from different climate-alarm group efforts, like the IPCC:
http://www.crescentofbetrayal.com/ClimateEmai_citations.htm
This focus on the obviously wrong variable is not science but “scientism” in the pejorative sense: political propaganda dressed up to look to the ignorant like it is scientific. It is a testament to the anti-scientific nature of climate alarm that such blatantly phony “science” can prosper widespread at the top of the climate science field.
James Griffen says “ Greenland is so called as from around 850AD to 1350AD it was largely covered in grass. ”
Really? So the Greenland ice cap is only 700 years old? Where did all the ice go in that period?
In the Article it says, regarding the figure from the GIPS2 ice core,
“Figure 10 shows that virtually all of the period from 1500 years ago to 5000 years ago was warmer than modern temperatures. This data is directly contrary to the Miller et al. conclusion that “average summer temperatures of the last ~100 years are now higher than any century in more than 44,000 years””
I have seen a discussion of that figure here somewhere before. Does anyone know where? I think the problem is that the last 100 years is not actually in the data, so the graph does not contradict Miller’s statement.
jimmi_the_dalek says:
In the Article it says, regarding the figure from the GIPS2 ice core,
“Figure 10 shows that virtually all of the period from 1500 years ago to 5000 years ago was warmer than modern temperatures. This data is directly contrary to the Miller et al. conclusion that “average summer temperatures of the last ~100 years are now higher than any century in more than 44,000 years””
I have seen a discussion of that figure here somewhere before. Does anyone know where? I think the problem is that the last 100 years is not actually in the data, so the graph does not contradict Miller’s statement.
THE TOP OF THE GISP2 ICE CORE IS 1950, SO IT DOESN’T INCLUDE THE GLOBAL COOLING FROM 1950 TO 1977, THE WARMING FROM 1978 TO 1998, OR THE SLIGHT COOLING SINCE 1999. BUT IT REALLY MAKES LITTLE DIFFERENCE. ALSO NOTE THAT THE MILLER STATEMENT TAKES IN THE LAST CENTURY, NOT JUST THE 2013 TEMP. SO YES, THE GRAPH DOES CONTRADICT THE MILLER ET AL. STATEMENT
(why all the caps)
Can you give a reference for that starting date please, and for the figure 10, or the data from which figure 10 was constructed.
Data for Fig 10 are from GISP2 ice core oxygen isotope measurements by Stuiver and Grootes, 1999. Listed below is the text heading for the data.
Complete GISP2 continuous measurements listing
This file contains the entire continuous GISP2 delta 18O sample data set (excluding the silty ice samples, which are published separately), measured at the University of Washington’s Quaternary Isotope Laboratory, as of March 5, 1999.
The data columns represent:
Depth Top depth of each interval, in meters. Samples are continuous unless specifically noted.
Age Layer count age at the given depth (in yr BP), where 0 BP represents AD 1950 summer to AD 1949 summer. Age corresponds to the top of the interval, unless noted otherwise.
Del 18O Mean 18O value (in per mil) over the interval starting at the indicated top depth. Standard deviation in a single 18O measurement is 0.14 per mil. Multiple measurements (such as in the data sets below) reduce the standard deviation to the 0.05 to 0.1 per mil range.
You can access the data at
http://depts.washington.edu/qil/datasets/gisp2_main.html
OK thanks, that clears something up. However the graphs described as “Modified from Cuffy and Clow, 1997; Alley,2000” are not so much modified as completely replotted, and the caption says “Years before present (AD 2000)” so is the caption wrong? Also the first data point on the graph appears to be “95” (though the resolution is not sufficient to tell if that really is the beginning of the scale). Is the 95, 95 years before 2000 or 95 before 1950? Where are the actual values that were plotted? As a further complication the link in your previous posts gives vales for 18Oxygen data up to 1987 (year -37 relative to 1950!). Is this data too recent to be reliable (i.e the ice has not sealed)?
The Holocene temperature curve came from the NOAA Paleoclimatology Program and World Data Center for Paleoclimatology, Boulder, IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2004-013 ,. It was placed there by Richard Alley (last updated 3/2004). The graph was a smoothed curve by Alley based on GISP2 Ice Core Temperature and Accumulation Data
NOAA Paleoclimatology Program and World Data Center for Paleoclimatology, Boulder, CO.
SUGGESTED DATA CITATION: Alley, R.B.. 2004.
NAME OF DATA SET: GISP2 Ice Core Temperature and Accumulation Data
LAST UPDATE: 3/2004 (Original Receipt by WDC Paleo)
CONTRIBUTOR: Richard Alley, Pennsylvania State University.
IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2004-013
GISP2 Ice Core Temperature and Accumulation Data.
IGBP PAGES/World Data Center for Paleoclimatology
Data Contribution Series #2004-013.
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.
Alley, R.B., 2000, The Younger Dryas cold interval as viewed from central Greenland: Quaternary Science Reviews, vol. 19, p.213-226.
Cuffey, K.M., and G.D. Clow. 1997. Temperature, accumulation, and ice sheet
elevation in central Greenland through the last deglacial transition.
Journal of Geophysical Research 102:26383-26396.
PERIOD OF RECORD: 49 KYrBP – present
Temperature interpretation based on stable isotope analysis, and ice accumulation data, from the GISP2 ice core, central Greenland. Data are smoothed from original measurements published by Cuffey and Clow (1997), as presented in Figure 1 of Alley (2000).
The GISP2 core is the source of the data (top 1950), but Alley’s plot is unclear as to the age of the top, probably because he used a smoothing filter. In any event, the age of the at the top of the core is 1950.
OK thanks again. That does pin it down. Unfortunately it means that the series does not begin in 1950, though it is given in terms of “years before 1950”. The top of the series begins like this :
Column 1: Age (thousand years before present)
Column 2: Temperature in central Greenland (degrees C)
Age Temperature (C)
0.0951409 -31.5913
0.10713 -31.622
0.113149 -31.6026
0.119205 -31.6002
0.119205 -31.598
0.125451 -31.6656
0.132407 -31.7235
0.138807 -31.7583
0.145126 -31.8098
Note the first entry, 0.095 ky , i.e.95 years before 1950, or 1855, so the whole of 20th century is missing, and even if the Greenland temperatures are a good proxy for the world as a whole, you cannot make comparisons with the last 100 years (unless you were to add the modern instrumental record to the ice core values).
The age on Alley’s original graph reads “Age before present (2000 AD)” so that would presumably put the date of his youngest data at 1905 if you take his label at face value. The age of the original graph by Cuffy and Clow (1997) is shown as “Thousands of years before present” and since the core top is 1950, “present” = 1950. Alley’s curve is based on the data from Cuffy and Clow. As I pointed out earlier, if you ‘add’ the cooling from 1950 to 1977, the warming from 1978 to 1998, and the slight cooling from 1999 to present, the temp of the ‘last century’ is not going to top the temp of 90% of past 10,000 years.
If you plot the oxygen isotope data, rather the temp itself, the youngest date is 1950 and it is clear that adding the last 50 (or 63 to 2013) years, is not going to make the ‘last century’ as warm as 90% of the past 10,000 years.
It’s not Alley’s graph.
I discovered where I had seen this before. There is a WUWT thread
http://wattsupwiththat.com/2013/04/13/crowdsourcing-the-wuwt-paleoclimate-reference-page-disputed-graphs-alley-2000/
which rejects the idea that age before present is AD 2000 in favor of 1950.
Since the WUWT community has already decided, perhaps you had better fix the caption.
Jimmi_the_dalek says:
“..and even if the Greenland temperatures are a good proxy for the world as a whole..”
Yet again, Greenland and Baffin Island temperatures are an INVERSE PROXY for the temperate zone.
Given the fact that 4400-4800 years ago was very warm in the temperate zone, the major expansion period for many civilisations, and that the cold period that caused the collapse of many of them around 3200 BP, what does that tell us about around 1000AD and the 8.2Kyr event?
http://smpro.ca/crunch/GISP2Civil.png
http://mclean.ch/climate/figures_2/Vostok_to_10Kybp.gif
[SNIP – A valid email address is required here, fake ones don’t cut it – mod]
At inter-annual to decadal scales, the peaks and troughs in Greenland ice core temperature proxies are nearly all the inverse of what we see through CET:
http://www.21stcentech.com/wp-content/uploads/2012/07/Greenland-ice-core-data.png
http://climexp.knmi.nl/data/tcet.dat