Guest post by David Middleton
The recent return of the Warming Island AGW myth inspired me to build a climate reconstruction for the Greenland Sea region.
Temperature Reconstruction
I performed a GISS station search centered on 71.4 N latitude, 23.5 W longitude and downloaded the 12 GISS/GHCN instrumental records with at least 60 years of continuous data up to 2011.
Next I calculated a temperature anomaly relative to 1961-1990 for each of the 12 stations and then averaged them together to create a temperature reconstruction. The climate in the Warming Island area is statistically indistinguishable from that of the 1930’s.
Then I took that reconstruction back to 1000 AD with the GISP2 ice core Ar-N2 data (Kobashi et al., 2010)…
The Modern Warming is also statistically indistinguishable from the Medieval Warm Period in the Warming Island / Greenland Sea region.
Arctic Sea Ice Reconstruction
It occurred to me that there might just be a relationship between the temperature anomaly and the Arctic sea ice extent. So I went to Wood for Trees and downloaded the historical NSIDC Arctic Sea Ice Index. Then I cross plotted an annual 13-month running average of the sea ice index against the average of the station anomalies and the GISP2 reconstruction (Kobashi et al., 2010) and found a pretty good correlation (R-squared = 0.67)…
Using the equation “Sea Ice Index = (-0.5976 * Temp. Anom.)+12.374” I calculated a Model Sea Ice Index.
The “Model Sea Ice Index” (white curve) is very similar to the measured sea ice index (cyan curve)…
Using the same equation, I extrapolated the Model Sea Ice Index back to 1000 AD using the GISP2 temperature data from Kobashi et al., 2010…
The model suggests that Arctic sea ice had been steadily expanding from ca. 1150 AD up until ca. 1800 AD and has been declining since ca. 1800 AD.
Next, I carried the model back to the Early Holocene using the Alley, 2000 GISP2 reconstruction…
This suggests that the sea ice contraction during the instrumental era (1979-2011) is not particularly remarkable.
Calibrating the Model
Realizing that my model has been extrapolated about 8,000 years away from real data, I decided to compare it to some real data. McKay et al., 2008 demonstrated that the modern Arctic sea ice cover is anomalously high and the Arctic summer sea surface temperature is anomalously low relative to the rest of the Holocene…
Modern sea-ice cover in the study area, expressed here as the number of months/year with >50% coverage, averages 10.6 ±1.2 months/year… Present day SST and SSS in August are 1.1 ± 2.4 8C and 28.5 ±1.3, respectively… In the Holocene record of core HLY0501-05, sea-ice cover has ranged between 5.5 and 9 months/year, summer SSS has varied between 22 and 30, and summer SST has ranged from 3 to 7.5 8C (Fig. 7).
My GISP2 (Alley, 2000) sea ice model is generally consistent with McKay et al., 2008…
Conclusion
“Move along, there’s nothing to see here.” The Arctic sea ice has “been there and done that” many times over the last 10,000 years without any anthropogenic assistance.
References
Alley, R.B. 2000. The Younger Dryas cold interval as viewed from central Greenland. Quaternary Science Reviews 19:213-226.
Kobashi, T., J.P. Severinghaus, J.-M. Barnola, K. Kawamura, T. Carter, and T. Nakaegawa. 2010. Persistent multi-decadal Greenland temperature fluctuation through the last millennium. Climatic Change, Vol. 100, pp. 733-756.
McKay, J.L., A. de Vernal, C. Hillaire-Marcel, C. Not, L. Polyak, and D. Darby. 2008. Holocene fluctuations in Arctic sea-ice cover: dinocyst-based reconstructions for the eastern Chukchi Sea. Can. J. Earth Sci. 45: 1377–1397
Michaels, P. 2008. “Warming Island”—Another Global Warming Myth Exposed.World Climate Report.
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You do realize that McKay et al 2008 was about the Chukchi Sea and not the entire Arctic?
Could you also do a temperature reconstruction for the North coast of Ellesmere Island where apparently ice shelves that have been there for 3000-5500 years are rapidly disappearing?
Cheers!
David Middleton
Nice work-well done!
My own study showed considerable arctic ice melting around 1800 to 1860 which fits in nicely with your own paper. At that time the Royal Society mounted an expedition to investigate the causes.
http://wattsupwiththat.com/2009/06/20/historic-variation-in-arctic-ice/#more-8688
There then seems to have been a partial recovery, with a further notable down turn from 1919-1939 which my colleague Dr Arnd Bernaerts wrote about here
http://www.arctic-heats-up.com/chapter_1.html
There then seems to have been another partial recovery until the advent of the satellite era which marked a relative high point in the amount of arctic ice, which has declined ever since..
Arctic ice melt is a regular occurrence with a downwards trend probably from around 1750 or so, which Hubert Lamb and others mark as being the start of the glacier retreat we can witness today. As well as the Vikings a thousand years ago we also have the evidence of Arctic civilisation in the form of the Ipiatuk some 3000 years ago, so we really should stop thinking about the current episode as being unique.
tonyb
“the warmest year in the extended Greenland temperature
record is 1941, while the 1930s and 1940s are the warmest decades”
http://www.cru.uea.ac.uk/cru/data/greenland/vintheretal2006.pdf
http://www.dmi.dk/dmi/index/klima/klimaet_indtil_nu/temperaturen_i_groenland.htm
That’s worth a paper. I will look for it in around 3-4 years after (if) it gets through the buddy peer review.
David Middleton
Excellent work.
Thank you.
Yes, global mean temperature is cyclic as shown by the following data
http://bit.ly/ocY95R
Beautifully and comprehensively presented in a way that even this non-scientist can understand. Thank you David.
Nice work!
This rightly makes a mockery of this latest AGW myth, which seems to have duped a lot of people into thinking it’s both unprecedented and a new name for Warming Island – both of which are wrong.
The well-known fact that the Vikings settled there and called it Greenland at a time when they could grow crops, raise livestock, and bury their dead in ground which is now permafrost, rarely seems to see the light of day amidst the MSM AGW hysteria.
Sadly, as I say, lots of people have been duped – just as they were by the Row To Pole jokers. Most Hanoi-ing, as they say in Vietnam. }:o(
The alarmist method of choosing summer to measure ice loss and scream ‘AGW’ but ignore the winter freeze, regardless of the depth of that freeze, shows a complete one sided cherry picked system of argument which proves nothing.
The cyclicity of climate would dictate ice area changing to follow the cycles.
Thanks for making the seemingly obvious more obvious for the alarmists who might change the habits of a lifetime and actually read this.
A very good analysis of available information that within itself cuts most of the legs out from under AGW.
Correction: Kobashi et al.,2010 is a nitrogen isotope reconstruction, not d18O.
Scottish Sceptic says:
September 29, 2011 at 1:05 am
That’s worth a paper. I will look for it in around 3-4 years after (if) it gets through the buddy peer review.
————————
Why so long? I would expect a pal/peer reviewed paper by Friday.
By today’s standards. /sarc off
Same empty fruitbowl with some picked cherries. BTDT.
A textbook example of loss of high frequency information in ice data. Nice work Willis. It seems this sort of analysis is out of the reach of anyone with the term “climatologist” in their CV. Perhaps that’s the issue that will be the most challenging scientific investigation.
Ergo: The actual intent of Mann, Gore, Jones, et al, is to make the next natural cooling event much stronger and thereby initiate the next glacial cycle ASAP. The overall impact will be a tremendous reduction in human population, the destruction of modern civilization, a significant reduction in sealevels, a fantastic expansion in the population of ‘desireable’ species, and an absolutely phenominal expansion in new beachfront property for the rich-n-famous worldwide.
Who said these guys were flakes? I really can’t get it out of my head that Soros is behind all this somewhere, and I just can’t imagine how he himself expects to profit from it all. When ‘Fat Albert’ starts talking about everyone chipping in to build a pyrimid for ‘Big George’ you’ll know the cat’s out of the bag.
I just don’t get it! WHY?
If YOU can do it, then THEY should be able to do it too, but, as we all know, that would be VERY inconvenient, indeed.
They’re really not interested in testable science, or historical fact (or likelihood), only the religion and pandering to their funders.
Not much grant money on the horizon for your efforts. However if you could do a Jones/Mann obfuscation and show a potential but untrue 21st Century Arctic AGW meltdown you could gather squillions of dollar/pound/euros to continue the lie!
Inconvenience notwithstanding.
Michael D Smith says:
September 29, 2011 at 4:42 am
“A textbook example of loss of high frequency information in ice data. Nice work Willis.”
err… I know Willis E. does great work around here, but give credit to David Middleton where credit is due… 🙂
I am not sure to mix instrumental record with GISP2 data. More, GISP2 ends in 1905 (but not on your graph) so not easy to calibrate them against each other.
There is a nice relation between Arctic SST and ice extent. In the past I did the ice extent reconstruction back to 1900 based on Arctic SST as well. Add the albedo amplifying effect and it might be not far off.
Really good article David.
Günther Kirschbaum says:
September 29, 2011 at 12:39 am
You do realize that McKay et al 2008 was about the Chukchi Sea and not the entire Arctic?
I meant to point that out..
The Greenland Sea temperature derived sea ice model’s consistency with a foram-derived Chukchi Sea ice reconstruction is a good check on the validity of the model.
Could you also do a temperature reconstruction for the North coast of Ellesmere Island where apparently ice shelves that have been there for 3000-5500 years are rapidly disappearing?
Cheers!
I don’t think there are that many long record-length GISS stations and I’m not aware of any decent ice core records for the Ellesmere Island area.
My blockquotes are off a bit in my last two comments.
I consider it a compliment of the highest order to be confused with Willis!
The amplitude attenuation with frequency loss is also pretty obvious. I often wonder if the Hockey Team ever heard of Nyquist… And I seriously doubt any of them has ever processed seismic reflection data.
The Kobashi N2-Ar reconstruction goes up to 1950 and has temperature data up to 1993 (modeled from borehole temperatures).
I guess I’ll have to keep my “day job”… /Sarc