Guest post by Verity Jones
Man is not the primary cause of change in the Arctic says book by Russian scientists
Forget the orthodox view of Arctic climate change – this book has a very different message. (h/t to WUWT commenter Enneagram)
Published last year, this is a synthesis of work by the Russian Arctic and Antarctic Research Institute (AARI). It sets out the data and experience of scientists over 85 years, drawing together much already published in the area. For a book that is billed under a climate change heading, this is actually more an antidote to the hype usually associated with warming in the Arctic. A few pages of each chapter are available on-line and even that is well worth reading; no doubt even better in its entirety.
The Preface sets the tone of the book very clearly – “.…scientists have predicted a significant decrease in sea-ice extent in the Arctic and even its complete disappearance in the summertime by the end of the 21st century. This monograph presents results of studies of climatic system changes in the Arctic, focused on ice cover, that do not justify such extreme conclusions.” “Many studies and international projects, such as the Arctic Climate Impact Assessment (ACIA), attribute the air temperature increase during the last quarter of the 20th century exclusively to accumulation of greenhouse gases in the atmosphere. However these studies typically do not account for natural hydrometeorological fluctuations whose effects on multiyear variability, as this monograph shows, can far exceed the anthropogenic impact on climate.”
The book begins by examining the major effects of the Polar Ice caps and their overall stability on Earth’s climate – affecting albedo, and regulating the heat flux from the sea to atmosphere. Climate variations are discussed and the WMO’s “30 year average” definition of climate is not considered applicable in the Arctic because fluctuations in the polar climate are so large.
Chapter 2 looks at what is known about changes in sea ice in the 20th century. The Russian data sets probably hold the most extensive information available for the first half of the century due to interest in the Northern Sea Route in the 1930s. In addition, measurements of ice thickness also go back to the middle of the 1930s when they were taken regularly for coast-bound ice at many of the Polar stations.
It is particularly interesting what they say about Arctic air temperatures (Chapter 4). “Periodic cooling and warming events are evident in air temperature fluctuations in the Arctic during the 20th century, similar to changes in ice cover.” A cool period at the beginning of the 20th century was followed by what is commonly referred to as the “Arctic Warming Period” in the 1920s-1940s. Relative cooling was widespread between the late 1950s to late 1970s, followed by the current warming period peaking in recent years. Gridded average temperature anomalies for 70°-85°N produce a curve that fits a polynomial trend to the sixth power and the cycle periodicity is 50-60 years (Figure 4.1). Other indicators in Arctic and Antarctic support this cycle and show its global nature. On the subject of polar amplification, whereby weather and climate variability increase with latitude, a number of models and explanations are discussed. None of these involve CO2.
The authors point out there is an abundance of hypotheses as to the possible causes of climate and ice variation and climate change (a ‘long-term’ phenomenon) but these lack detailed long-term data. They state “where data do exist, we should prefer data to computer models”; they believe model projections of future ice area fluctuations are unreliable. Actually, they have some deliciously scathing remarks about climate models.
“The models neglect natural fluctuations because they have no means of incorporating them, and put the entire blame for climate changes since the 19th century on human activity.”
On possible future changes they predict that “..in the 21st century, oscillatory (rather than unidirectional) ice extent changes will continue to dominate Arctic seas.” A new ice maximum in 2030-2035 is predicted (Figure 6.1) and this will have major implications for shipping in the region.
From the results of spectral analyses, they conclude that there are 50-60 year cycles and less prevalent ones at 20 years, 8-12 years and 2-3 years. These are closely related to variations in general atmospheric circulation. In the longer term the decreasing trend of ice extent may be a segment of a 200 year cyclic variation responsible for the Medieval Warm Period and Little Ice Age. Much of the discussion about solar effects is behind the paywall for the book, however there are some strong conclusions about solar effects on Arctic climate. Despite the small variation in Total Solar irradiance (TSI) through solar cycles, solar activity may have a greater effect on high latitudes because of interaction with the Earth’s magnetic field. Solar system “dissymmetry” (barycentre) influences are also mentioned as closely corresponding to the 60 year cycles.
The authors conclude that the simulation by the general circulation models does not appear to reflect the cyclic features in Arctic ice extent and climate, and, if their cyclic interpretations of climate variation are correct, ice cover will continue to fluctuate as there is little connection with the anthropogenic burning of fossil fuels.
Climate Change in Eurasian Arctic Shelf Seas: Centennial Ice Cover Observations. Authors: Ivan E. Frolov, Zalmann M. Gudkovich, Valery P. Karklin, Evgeny G. Kovalev, and Vasily M. Smolyanitsky. Published by Springer/Praxis (2009) ISBN 9783540858744
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Verity is one of WUWT’s moderators and contributors. She also has her own website at Digging in The Clay. Be sure to visit it and bookmark it – Anthony
And there is still available the photo of an american submarine at the North Pole in March during the ’30 sitting in open water. But If I were you Gatesie I would ignore it. It’s all lies, you know. /sarc off
Now if that would have been a ship it would really have been impressive. But you know, submarines can dive under and travel below the ice and pop up in one of the leads that always open up in winter. And that’s exactly what they did.
It was a cool feat, but doesn’t mean anything with regards to the state of the Arctic sea ice in the past.
No submarine reached the North Pole in the 30s People who don’t know that are idiots.
Verity Jones says on October 17, 2010 at 1:36 am
What is not clear from the those pages and following some of the links is whether or not they could make the journey without the need for ice breakers … Otto Schmidt is said to have used steaming icebreakers … however, the route might have been ice free for some months during that time, but it is not clear from what you have quoted.
Please look at this picture from Daily Artic Sea Ice:
http://arctic.atmos.uiuc.edu/cryosphere/
From 10/12/09 vs comparison 10/10/10 has it stopped snowing everywhere????
Peter Taylor (October 17, 2010 at 8:26 am)
Fascinating comment – thank you.
Richard Sharpe (October 17, 2010 at 11:08 am)
There are plenty of information sources on the web. A quick search threw up this: http://www.cnrs-scrn.org/northern_mariner/vol03/tnm_3_2_1-17.pdf
It looks as if ice-strengthened ships and icebreakers were used from early days. The does not tell us very much about the conditions of the ice over the full length of the passage. As we saw this year the land fast ice holds on in certain regions such as the Lena Delta and Cape Chelyuskin and opening of a lead can be a matter of a fortunate shift of wind. When you are a commercial venture delays cost money and increase risk; although an icebreaker also costs money it allows certainty. It is likely then that reduced ice conditions in many parts of the Northern Sea Route led the Russians to believe it was viable in the early 1930s and to invest resources in it. Technological improvements (more powerful icebreakers) have continued its use, but the season does vary by year.
Fred H. Haynie says: “If you are looking for a tipping point, it will not be run-a-way global warming. It will be if the Arctic freeze/thaw pump shuts down and we plunge into our next ice age. At present it appears that it is not slowing down.”
Yes. Based on our understanding of past history, that ice age tipping point may actually exist, unlike the fictitious runaway warming scenario. If we’re entering another ice age, we may have a few more Arctic melt cycles to go before the plunge.
This short documentary studies the geological evolution that has gone on for millions of years in the High Arctic. Following the evidence of glaciers that have advanced and receded, the film also traces life forms that have changed with the climate.
http://www.nfb.ca/film/face_of_the_high_arctic/
Dalton Muir, 1958.
richard telford says:
October 17, 2010 at 9:09 am
Any information on your numerical modeling, Richard? I’d like to know how you did your “600 run”…
If you don’t have any documentation, that’s OK. Appears to be the norm (with some notable exceptions) in the climate science world…
quoting an earlier item … [i]And there is still available the photo of an american submarine at the North Pole in March during the ’30 sitting in open water. But If I were you Gatesie I would ignore it. It’s all lies, you know. /sarc off[/i]
Günther Kirschbaum says:
October 17, 2010 at 9:36 am
Now if that would have been a ship it would really have been impressive. But you know, submarines can dive under and travel below the ice and pop up in one of the leads that always open up in winter. And that’s exactly what they did.
It was a cool feat, but doesn’t mean anything with regards to the state of the Arctic sea ice in the past.
—…—…
A typo no doubt: There were no subs under the ice until the first nuclear-powered runs under the ice in the mid-50’s. Earlier submaribnes needed to surface every 12- 18 hours to survive, and could NOT go under the ice safely under any circumstances due to their cluttered topside and conning towers.
Regardless – Did you forget about the SS Manhattan supertanker that lead an ice-breaker through the Arctic ice in the early 70’s? The ice breaker was along in case of emergencies, but the tanker proved much better at clearing a lane.
Frank K. says:
October 18, 2010 at 6:35 am
I don’t do the modelling – I use the output for pseudoproxies. Some documentation is published at
Otterå, O. H., M. Bentsen, I. Bethke and N.G. Kvamstø (2009): Simulated pre-industrial climate in Bergen Climate Model (version 2): model description and large- scale circulation features, Geosci. Model Dev., 2, 197- 212, 2009.
http://www.geosci-model-dev.net/2/197/2009/gmd-2-197-2009.html
Peter Taylor says:
October 17, 2010 at 8:26 am
[i]
I have a chapter in ‘Chill’ called ‘Poles Apart’ which contrasts the Arctic and Antarctic environments and notes that they tend to trend in opposite directions. Both are regions of permament heat deficit and rely on transport of heat from ocean basins to melt the ice in summer. When researching the book, I was immediately struck by the wealth of papers on the Arctic cycles – especially the 60 year Surface Air Temperatures (SATs) which lag a pressure oscillation across the Arctic basin. Nobody knows what causes the cycle, but virtually all ‘real’ Arctic specialists know about it, as well as the long term cycles that are recorded in the ice-caps thoughout the ice-age and in the Holocene as well.
[/i]
First, a heart-felt “Thank You” for your efforts. And my hope the book continues to do well.
Second. You go on to cover several other cycles of different lengths, and of different magnitudes.
When plotted together over a 2200 year period, do the combinations of all of the known multi-year climate cycles add together in sufficient waves to create the Medieval Warm Period and Roman Warm Period?
This is interesting, but without a similar run before or after it does not tell us much.
Where did it go to? When did it do that? Which route did it take? Much better at clearing a land sounds like it had to break some ice … is that so.
Don’t get me wrong. I am looking for ironclad evidence that ice conditions were similar to those today …
Well, it’s nice and I’m sure quite believable, but didn’t they have to have some models to make future predictions?
Richard telford says:
October 18, 2010 at 2:11 pm
Frank K. says:
October 18, 2010 at 6:35 am
I don’t do the modelling – I use the output for pseudoproxies. Some documentation is published at
Otterå, O. H., M. Bentsen, I. Bethke and N.G. Kvamstø (2009): Simulated pre-industrial climate in Bergen Climate Model (version 2): model description and large- scale circulation features, Geosci. Model Dev., 2, 197- 212, 2009.
http://www.geosci-model-dev.net/2/197/2009/gmd-2-197-2009.html
—
Sorry Richard – that is NOT documentation and is almost as bad as the junk at GISS…
Why can’t these scientists actually write down the differential equations and numerical algorithms they’re attempting to solve? Is it too much to ask? Apparently so…
Peter Taylor:
In your post of October 17 you stated:
“it was easy to predict that the ice would come back in 2008 and 2009, stall a bit in 2010 due to the ENSO event, and will resume in 2011. ”
Why do you consider that the ice has “come back” at all?
The average age and volume of the ice appear to continue to decline over this period with 2010 possibly at the lowest level in the period of satellite records. When these items are included in the analysis of the state of the arctic ice it appears possible to conclude that the ice has continued to decline over this period even though the minimum ice extent is slightly higher than 2007.
http://soa.arcus.org/abstracts/trends-and-patterns-sea-ice-age-distributions-within-arctic-basin-and-their-implications-c
If you are using the arctic ice extent at the minimum as the sole data point for making the claim of a come back, then the claim does not appear to be valid. If March 31 were used as the test point it would appear the arctic had almost made a full recovery, which we know is false. If you pick the period of mid May to the end of June, then you would conclude (based on NSIDC extent figures) that 2010 was the worst showing in the satellite record for any year and if you picked the month of July, you would say it was the second worst year.
Choosing the arctic minimum ice extent as the sole measure of whether a recovery has occurred appears to be a false measure of the ice condition as the ice that survives at the minimum may consist of ever increasing percentages of relatively thin first and second year ice which is particularly vulnerable to future declines. While both volume and age are difficult to determine, that does not mean these factors should be ignored in determining if the ice has “come back”. Until there is a pick-up in the age and volume of the ice it would not appear that any recovery is underway. A full recovery would only occur if the volume, age and extent of ice older than 2 years returns to levels last seen in 2000.
NO REBOUND OF ARCTIC ICE INDICATED IN OCTOBER 2010.
As of October 25th, the arctic ice extent anomaly was at -1.412 million km2 and the temperatures are slightly above average per the Danish Meteorological Institute – Mean Temperature above 80°N with a recent sharp upward spike that has since declined, but is still above average. The Antarctic ice extent anomaly is +.376 million km2.
Info was obtained from the excellent sea ice page maintained at: http://wattsupwiththat.com/reference-pages/sea-ice-page/
WILL ARCTIC SEA ICE EXTENT BE BELOW AVERAGE FOR OCT. 31st FOR 2007 THROUGH 2009?
The average sea ice extent at October 31st for the years 2002 through 2006 was fairly steady and averaged 8,768,875 km2. Since then, the values have bounced around with the 2007 through 2009 average at 8,402,396 km2
Per IJIS the arctic sea ice extent value is: 7,635,156 km2 (October 25, 2010).
Predicting sea ice extent, even 6 days out, is hazardous as the last 10 days have shown an average daily increase of approximately 75,000 km2 daily while the last three years have shown an average daily increase for the period October 25th through 31st period of approximately 125,000 km2.
At this point, October 2010 looks as if it will be between the record minimum in 2007 and the second lowest minimum recorded in 2009, but we will have to wait to see what happens. This would put it slightly below the 2007 to 2009 average.
No rebound in arctic ice is indicated by these numbers, but maybe next month will see a faster increase in the spread of first year ice.
A sudden increase in first year ice will not be an indication of recovery if the ice does not make it through the 2011 melt season and additional perennial ice is transported out of the arctic through the Fram and Nares straits.
The rate of sea ice extent increase may have slowed recently due to transport through the straits and the quality of arctic ice continues to decline as thin first year ice is replacing perennial ice, which tends to be thicker than first year ice. An animation showing the ice transport through the Fram and Nares straits that continuously is updated can be seen by clicking the play button at:
http://neven1.typepad.com/blog/2010/09/open-thread-1.html?cid=6a0133f03a1e37970b0134881af0ac970c
Based on data provided by IJIS the October 31 sea ice extent for 2002 through 2009 was:
October 31 Sea Ice Extent km2
2002 8,799,844
2003 8,729,375 10-28- value 10-31 not asvailable
2004 8,735,156
2005 8,880,000
2006 8,700,000
2007 8,003,281
2008 8,892,344
2009 8,311,563
Average
8,768,875 2002 to 2006
8,402,396 2007 to 2009
Data was accessed using the “Data Download” button at:
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
REPLY: heh, uber spin this: “Mean Temperature above 80°N with a recent sharp upward spike that has since declined, but is still above average.” yet still at 256 kelvin or -17.15 degrees Celsius. This happens every year…no news. – Anthony
Anthony:
Thank you for taking the time from your busy schedule to read the post above. Sorry for distracting you with the temperature information in a post about ice extent.
As more ice is exported through the Fram and Nares straits (see animation at link in previous post), the sea ice extent growth has slowed. Per IJIS there was 7,719,531 at October 27th. At this pace, October 31 could represent a record low for that date.
NO REBOUND FOR ARCTIC ICE THAT IS AT LEAST FIVE YEARS OLD
Per the NSIDC:
“Last winter, the wind patterns associated with the negative phase of the Arctic Oscillation transported a great deal of multiyear ice from the coast of the Canadian Arctic into the Beaufort and Chukchi seas. Scientists speculated that much of this ice, some five years or older, would survive the summer melt period. Instead, it mostly melted away. At the end of the summer 2010, under 15% of the ice remaining the Arctic was more than two years old, compared to 50 to 60% during the 1980s. There is virtually none of the oldest (at least five years old) ice remaining in the Arctic (less than 60,000 square kilometers [23,000 square miles] compared to 2 million square kilometers [722,000 square miles] during the 1980s).
Whether younger multiyear ice (two or three years old) in the Arctic Ocean will continue to age and thicken depends on two things: first, how much of that ice stays in the Arctic instead of exiting into the North Atlantic through Fram Strait; and second, whether the ice survives its transit across the Beaufort and Chukchi Seas or instead melts away.”
SEE VIDEO AT:
http://www.arctic.noaa.gov/reportcard/
See visual representations of ice age at:
http://www.arctic.noaa.gov/reportcard/
So far in 2010, there have been no days in the IJIS records that show a recovery of 500,000 km2 (April 7th came close) compared to the same day in 2009 October 27 is below the 2009 level.
The 500,000 km2 recovery prediction made below did not occur as the September 2010 average of 4.9 million km2 calculated by NSIDC was 460,000 km2 below the 2009 amount of 5.36 million km2. http://nsidc.org/news/press/20091005_minimumpr.html
http://wattsupwiththat.com/2010/02/09/prediction-arctic-ice-will-continue-to-recover-this-summer/
2011 PREDICTION
THE NSIDC MINIMUM SEPTEMBER AVERAGE IN 2011 WILL BE BELOW THE MINIMUM RECORD SET IN 2005.
No rebound currently, but that is not what the post was saying. You are stating information that is readily available to all and of which we are aware. Try reading the book – it too issues a prediction.
“it is predicted that in the 21st century, oscillatory (rather than unidirectional) ice extent changes in the Arctic seas will continue. During the 2020s-2040s, an increase in sea ice extent is projected, with the maximum around 2030 in the eastern seas and around 2035 in the western seas.”
Figure 6.1 The predition references three peer reviewed papers. These may be in Russian but there is no less rigour in Russian journals than in English ones and now that we know about the closed shop revealed by Climategate, indeed there may be more.
So you might be right in your prediction for Sept 2011, but let’s see what the next 10 years bring. And shouting will not change what will happen either way.
Verity Jones:
Thank you for your respone, and I apologize for using capital letters (at least they were not in bold.)
I have no issue with the source of the book being Russian and I am not challenging the accuracy of the data being employed. It iis the representations of the scope of the conclusions of the book and the authors’ certainty with respect to the conclusions as presented in the original post that are generating my skepticism that this single source of information proves that a rebound will occur. While you state “Man is not the primary cause of change in the Arctic” this statement does not prove that humans are not having an impact that is causing Arctic ice to decline at a faster rate than it otherwise would or that changes in the future will not be driven to an increasing extent by additional CO2 forcing as humans cause CO2 levels to rise.
Some of the data you cited in the original post and the book appear to support the possibility of long-term CO2 warming.
Figure 4.1 and6.1 appear to be temperature anomaly charts and not an ice extent chart. The charts appear to support the existence of an additional warming trend in this area of the arctic that is operating in conjunction with the identified cycles as the 1970 low is higher than the 1910 low and the 2000 high is higher than the 1940 high. Even if the 50-60 year cycle is valid, these observations appear to support the existence of an additional factor which is causing an upward shift in the temperature cycle that could be a signature of CO2 warming. The extension of the line beyond 2000 in the figures does not appear to be supported by the trends for the previous period as the 2030 minimum anamoly is below the 1970 anamoly when it would appear that it should be above 1970 since 1970 and 2000 were above their respective prior points. The figure also shows the 2060 peak as being below the 2000 peak.
Why was the line for the future periods drawn in this fashion, is it based on a model prediction – if we can not trust models, why should we trust this forecast?
In the chart provided in the post from digging in clay above there is a data set going back to 1880. The data in the period 1880 to 1910 does not appear to show any trend. Was this data included in the analysis performed in the book? What is the cycle represented by the 30 year period of 1880 to 1910? Do each of the data sets in the digging with clay temperature anamoly chart separately follow the 50-60 year cycle or is it only the average of these data sets that follows the 50-60 year cycle trend?
The temperture anamoly cited in the original post is only being measured for latitude 70 to 85 degrees north. Does the observed temperature anamoly for latitude 60 to 70 degrees north show the same cycle?
The book appears to be analyzing the Russian shelf areas of the Arctic. The analysis in the book did not include data from the the period of 2004 through 2009 in determing the existence of the cycle. Does the analysis still hold if all areas of the arctic are included and the period 2004 to today is included? Another source that has read the book noted these weaknesses when it stated:
“I read through this book earlier this year, so I’m familiar with it. As the title (“Climate Change in the Eurasian Arctic Shelf Seas”) states, the book analyzes data only the Russian shelf regions of the Arctic – it doesn’t include the central Arctic or U.S./Canadian Arctic, where a significant portion of the decline has occurred over the past decades. Their conclusions are drawn from data through only 2003, so with the recent low years since then, the observed patterns of variability may no longer hold. (There is a final section in the book on 2003-2008 sea ice conditions, but these data are discussed independently and are not incorporated to update their analyses earlier in the book.)
The book only superficially examines ice thickness changes (again only in the Russian shelf regions) and does not examine the recent thickness data from ICESat or the ice age fields. Finally, as it states in conclusion #2: “These cyclic oscillations of sea ice extent were superimposed on the background consisting of a negative long-term linear trend that characterizes gradual decrease of sea ice extent during the 20th century and the beginning of the 21st century.” In other words, even in the Russian data, there is a decline. The authors suggest this decline could be indicative of a longer cycle, but admit that such a conclusion can only be “conjectured”.
So while the book provides useful data (Russian information is often difficult to obtain), their conclusions about reasons for the changes in overall Arctic sea ice and the state of sea ice in the coming decades are more limited than the book seems to suggest. Andy Mahoney (a former colleague of mine at NSIDC) and others also analyzed the Russian data in a paper published in 2008 (Mahoney et al., 2008 – a brief summary is here).”
http://wattsupwiththat.com/2010/10/21/summer-2010-in-the-arctic-and-other-sea-ice-topics/
The analysis of the sea ice extent data for the Russian shelf area using data from Russian sources noted that:
“We have acquired digitized historical ice charts of the Eurasian Arctic from the Arctic and Antarctic Research Institute (AARI) in St. Petersburg, Russia for the periods 1933 to 1992 and 1997 to 2006. We also have ice index data for the periods 1924 to 1933 and 1993 to 1996, creating an observational ice record that spans more than 80 years. From ice chart data, we have located the ice edge where possible in every chart and calculated seasonal ice extent anomalies for the marginal seas of the eastern Arctic. These results indicate that although there was also a retreat in autumn (annual minimum) sea ice extent in the early part of the 20th century, there was no apparent retreat in springtime (annual maximum). In recent years however, there has been a year-round retreat of eastern Arctic sea ice extent.”
Even the original post creates some doubt as to the length of the cycle when it states:
“From the results of spectral analyses, they conclude that there are 50-60 year cycles and less prevalent ones at 20 years, 8-12 years and 2-3 years. These are closely related to variations in general atmospheric circulation. In the longer term the decreasing trend of ice extent may be a segment of a 200 year cyclic variation responsible for the Medieval Warm Period and Little Ice Age.”
How do we know that the current period is not a part of a 200 year cycle of long term arctic ice decline?
I was also surprised by the reference to total solar irradience (TSI) as it appears that the arctic ice decline accelerated after 2000 even though TSI was declining http://icecap.us/images/uploads/ARCTIC12.jpg , thus the two do not show a close correlation for this period. This would indicate that forces other than TSI, such as CO2 forcing, may be contributing to changes in arctic ice extent and temperature.
Also, if “During the 2020s-2040s, an increase in sea ice extent is projected” why isn’t the date of the maximum extent 2040 instead “the maximum around 2030 in the eastern seas and around 2035 in the western seas”, what happens to the increase from 2035 to 2040?
The representation of the book by climate scientist Dr. Walt Meir and the Russian ice extent data appear to differ significantly from the post you left. Perhaps you are correct that I will need to get a copy and read through it.
“Some of the data you cited in the original post and the book appear to support the possibility of long-term CO2 warming.”
Yes, since we are still warming out of the little ice age that is what I would expect regardless of CO2 concentration.
“In the chart provided in the post from digging in clay above there is a data set going back to 1880. The data in the period 1880 to 1910 does not appear to show any trend. Was this data included in the analysis performed in the book? What is the cycle represented by the 30 year period of 1880 to 1910? Do each of the data sets in the digging with clay temperature anamoly chart separately follow the 50-60 year cycle or is it only the average of these data sets that follows the 50-60 year cycle trend?” The graph came from another posting http://diggingintheclay.wordpress.com/2010/09/01/in-search-of-cooling-trends/ (which was also featured on WUWT). No the analyses was not from the book. Yes each of the temperature sets roughly follow the pattern what is striking is how well they follow the pattern when you put them together. The pattern from 1880-1910 is cooling, but with some particularly cold excursions. This is one station. Such cold excursions are common even in warmer periods; if you look at nearby stations – Andenes, Alta Lufthavn, Gjesver, the same extreme excursions are there but the cooling down to 1910 is clearer.
“The temperture anamoly cited in the original post is only being measured for latitude 70 to 85 degrees north. Does the observed temperature anamoly for latitude 60 to 70 degrees north show the same cycle?”
You can find the same pattern at all lattitudes (again see – http://diggingintheclay.wordpress.com/2010/09/01/in-search-of-cooling-trends/) Not all stations show this pattern – an obvious reason would be an effect of city growth and urban warming, that could be a cause of deviation from the pattern.
Dr Meier’s opinions on the book are quite welcome and seem reasonable. I wish I had been able to comment on his post at the time. I find it interesting that the Russian’s conclusions are at odds with his own. Thank goodness scientists have the freedom to view data differently and reach alternate conclusions. I’d hate to live in a world where no-one came up with new ideas or analysis and it has been quite fun to see scientific orthodoxy turned on its head at times (one that comes to mind is the bacteria that are now an accepted cause of stomach ulcers and curable).
Dr Arnd Bernaerts, who has studied information available about the 1919-1939 Arctic warming, has written some interesting comments about the recent Arctic Report Card Update http://diggingintheclay.wordpress.com/2010/10/27/noaa-%E2%80%9Carctic-report-card-update-for-2010%E2%80%9D/ and aslo Tony Brown has previously written about the little known period 1815-60 when the Arctic ice melted and the Royal Society mounted an expedition to investigate the causes. http://wattsupwiththat.com/2009/06/20/historic-variation-in-arctic-ice/#more-8688
The current warmth in the Arctic may have reduced the ice to an extreme low, and I can understand the reasons why some very high profile scientists are saying that it will not recover, I just don’t accept the magnitude of climate sensitivity to CO2, therefore I believe the drivers of change to lie elsewhere with a more significant hope of recovery.
Verity Jones:
Thank you for taking the time to respond to the questions I left.
I appreciate you clearing up that the chart provided above was not from the book.
The NOAA Arctic Report Card appears to support my position that a recovery of arctic ice is not likely to occur. I will spend some time going through Arnd Bernaerts post and may leave a comment there. Hopefully this post relies on peer reviewed studies to support its comments, and I will also look at the historical reference post. Thank you for the references.
The book does not appear to have used the pre-1900 data you mention, and the station you selected does not appear to show cooling. The book used a 103 year period in a geographicly limited area to establish the existence of a 50-60 year cycle which it then projects 30-40 years into the future without identifying the specific forces that generate the cycle. Accepting that “model projections of future ice area fluctuations are unreliable” does not generate any confidence that we should rely on the rebound prediction of the model being suggested by this book.
In the chart you provided, there only appears to be one cooling period. You are assuming that this cooling was caused by non-human induced changes. This assumption may not be correct. What you have claimed to be a natural cycle may only be the general background of CO2 forced warming offset by cooling from aerosols or some other factor in the 1940 to 1970 period. Murray Mitchell, in the NOAA Weather Bureau’s Office of Climatology, collected a set of data over a fraction of the Northern Hemisphere—from 20 to 90 degrees North latitude. and found that Earth experienced a period of cooling (by about 0.3°C) from 1940 through 1970. Some studies indicated that the cooling during this period was caused by sulphate aerosols while a recent study looked at changes in sea surface temperatures.
Thompson, D., Wallace, J., Kennedy, J., & Jones, P. (2010). An abrupt drop in Northern Hemisphere sea surface temperature around 1970 Nature, 467 (7314), 444-447 DOI: 10.1038/nature09394
“The twentieth-century trend in global-mean surface temperature was not monotonic: temperatures rose from the start of the century to the 1940s, fell slightly during the middle part of the century, and rose rapidly from the mid-1970s onwards1. The warming–cooling–warming pattern of twentieth-century temperatures is typically interpreted as the superposition of long-term warming due to increasing greenhouse gases and either cooling due to a mid-twentieth century increase of sulphate aerosols in the troposphere2, 3, 4, or changes in the climate of the world’s oceans that evolve over decades (oscillatory multidecadal variability)2, 5. Loadings of sulphate aerosol in the troposphere are thought to have had a particularly important role in the differences in temperature trends between the Northern and Southern hemispheres during the decades following the Second World War2, 3, 4. Here we show that the hemispheric differences in temperature trends in the middle of the twentieth century stem largely from a rapid drop in Northern Hemisphere sea surface temperatures of about 0.3 °C between about 1968 and 1972. The timescale of the drop is shorter than that associated with either tropospheric aerosol loadings or previous characterizations of oscillatory multidecadal variability. The drop is evident in all available historical sea surface temperature data sets, is not traceable to changes in the attendant metadata, and is not linked to any known biases in surface temperature measurements. The drop is not concentrated in any discrete region of the Northern Hemisphere oceans, but its amplitude is largest over the northern North Atlantic.”
The drop in mid-century temperatures as Anthony would say is “old news”. http://www.globalchangeblog.com/2010/09/rethinking-the-mechanisms-of-20th-century-climate-warming/
That the Russian data can find the same signature in their area of the arctic is therefore not surprising. What is needed to support the position that Arctic ice will rebound is the identifcation of a forcing mechanism that will overide the known radiative forcing from CO2 and loss of albedo from the current ice retreat.
The most that it appears that I can get out of this book is that the authors have done an excellent job of data collection. Based on the additional information you have provided, I accept that the data in the book and the chart you have posted above are accurate.
Your post does not indicate that the book provided any explanation of the pattern based on radiative forcing or an explanation of how a change in current radiative forcing will occur in the future which will create a rebound in arctic sea ice extent. While I appreciate your efforts in providing the information of the existence of this database there is still a missing piece to your analysis. All you have proved is that the eurasian shelf shows a similar temperature pattern to the rest of the Northern Hemisphere over the last century. Show me the radiative forcing that will cause the temperature to decline and the ice to rebound and I will support your position.
“The basic concept of radiative forcing is one on which scientists — whatever their views on global warming or the IPCC — all seem to agree. Disagreements come into play in determining the actual value of that number.”
http://www.physorg.com/news187443399.html
I do not dispute that the recent decline in Arctic ice is more complex than saying it has occurred because of CO2 increases. There are clearly affects which have amplified CO2 radiative forcing. http://www.skepticalscience.com/What-causes-Arctic-amplification.html
A possible place to start in building a case for Arctic ice rebound would be to focus on a change in the Arctic Oscillation. http://nsidc.org/arcticmet/patterns/arctic_oscillation.html
The Arctic Oscillation was clearly a factor in the 2002 decline:
“Serreze believes that the September 2002 low-ice mark was reached due to unusually warm temperatures and frequent storms that worked in tandem to break up and melt the ice. The Arctic oscillation was in a positive phase the previous winter and appears to have played a role. But the Arctic Oscillation doesn’t explain everything, and there are signs that it may be moving back to a more neutral phase. Whether this will be just a temporary shift is not known. Yet the ice continues to retreat.
“The more recent years have shown indications of a recovery in the Arctic Oscillation towards more neutral conditions, but we’ve still seen decay in sea ice,” Serreze says. He wonders if the ice has thinned to a point where it has reached a threshold; a situation where thin ice and warming waters reinforce each other, regardless of pressure patterns like the Arctic Oscillation.”
http://earthobservatory.nasa.gov/Features/ArcticIce/arctic_ice2.php
The problem for the arctic ice, as the study below suggests, is “that strong positive ice–temperature feedbacks have emerged in the Arctic, increasing the chances of further rapid warming and sea ice loss”. Citing periods of prior ice loss and recovery are not relevant if the forces affecting the ice have changed. The net increase in radiative forcing from CO2 since 1850 would make any example of ice recovery from a previous low suspect as a predictor of future conditions, but I will check out the 1815-1860 information (Does this information refute that the Little Ice Age lasted until 1850?) to see if there are any examples of forcings that would support a future ice recovery.
http://www.nature.com/nature/journal/v464/n7293/full/nature09051.html
@Will Crump
you have too much time on your hands if you write such long comments; you should start your own blog.
So sulphate cooling? Well the abstract of the Thompson et al 2010 paper is misleading, because they admit:
and when we visualise the mid-century cooling it does seem rather global:
(description here)
Arctic ice loss from the poles can explained by transport of warmed water into the region, without invoking effects of CO2. It then has the effect of increasing the concentration of a more potent greenhouse gas – water vapour. From the last paper you linked to:
This results in an increase in cloudiness in the summer which would mitigate increased solar ocean warming; reduced sea ice cover at other times increases warming but also increased loss of thermal energy to space. Thus over a period of years we have mechanism to support ice recovery as the rest of the planet starts to cool also.
It is often said that due to the lack of humidity, CO2 should have greatest effect at high latitudes which are low in humidity. The paper measures up to 10% increase in humidity (June-Oct) in the decade studied, so I rather think H20 would trump CO2 in this case.
Verity Jones writes,
“@Will Crump
you have too much time on your hands if you write such long comments; you should start your own blog. ”
That remark deflects some thoughtful points and questions. For example, what physical mechanism drives these 60-year cycles?
@Gneiss
Deflects? I should have used a smiley – actually I meant to be complementary as well as alluding that he has more time than me and is very good at pulling out information he wishes to present. As such it seems many of his questions can be viewed as rhetorical. I certainly took them that way.
As for the mechanism driving the 60 year cycles – well if we knew that…
@Peter Taylor
Thanks for the more comprehensive answer. I answered with the resourses to hand, and I am only too aware of starting to scratch the surface of a vast literature on the area (Arctic).
Once again the sulphate cooling story emerges – does anybody bother to check a few facts: 1) anthropogenic sulphur was released at low altitudes, and in order to cool the planet, only those volcanic eruptions that penetrate to very high atltitudes are effective; 2) the various clean-air acts and sulphur reduction programmes of the EU and US, along with the collapse of the Russian and Eastern European economies were counterbalanced by other sources in industrialising countries, so globally, suplphur emissions did not reduce significantly, 3) the EU reductions kicked-in AFTER the data showed the end of global dimming, 4) global dimming AND subsequent brightening was a pattern seen in unpolluted areas of the southern hemisphere, 5) the brightening was measured as a flux of visible (warming) light to the surface – 70% of which is ocean, and this flux and subsequent heat transfer to land, is greater by a factor of 4 than the computed radiative forcing from CO2 (which is a computed figure relying upon models which are not entirely transparent – I suggest trying to read IPCC’s monograph on the concept!).
The point is that the IPCC suite of models ALL used a flawed set of assumptions relating to the 1945-1975 trough and produced a ‘fit’ (hindcasting) that convinced them the models were reliable. The Thompson et al paper is the first of the ‘backtrackers’ – and I am suspicious of the ‘teamwork’ that focuses on the ocean dip and pleads ignorance of the mechanisms, when equally they could be drawing attention to the use of flawed assumptions in the models!
The ‘dip’ from 1945 to 1975 changes shape the further north you go – in the Arctic you get a double ‘hump’ with 1940 showing a peak, and the second peak occurs 60-70 years later and varies at different points in the Arctic. We don’t know much about previous peaks and troughs, and the LIA period may have had a different pattern anyway. The crucial point is that whatever creates the trough is powerful enough to over-ride any CO2 forcing. Likewise, whatever drives the peaks can amplify that signal. It seems clear to me that the real CO2 signal is much smaller than computed.
The ONLY way to drive a global temperature signal in sea surface temperature (then transferred to land) when there is only slight long-term variability/trend in the solar TSI, is to alter cloud cover or atmospheric transparency (and this is the findings of the teams that showed the trough was a worldwide natural phenomenon). You can create significant changes in regional and I would say also global temperature by altering the SPATIAL distribution of cloud cover as well as or even without any percentage change in overall cover. This is because ‘global warming’ is not global – it is concentrated in the top 200m of the northern ocean gyres from whence it is transferred by westerly air currents to the land masses.
Arctic cloud cover increased by 14% from 1980 to 2000 (NOAA’s State of the Arctic Report has the data). Likewise we know that more warm water entered the Arctic basin from further south, ultimately drawn in by pressure changes and the shifting Beaufort gyre. The Arctic Oscillation – however longterm a phenomenon, may be linked to solar cycles or it may be a stochastic resonance phenomenon – but the pressure oscillation (followed by temperature changes) is real enough. What is not real are the general circulation models and radiative forcing calculations that now need revision.
We will see more of the truth over the next few years. We need to monitor the export of heat from further south – via ocean currents and cloud, and this already looks to be depriving the Arctic of heat (the Arctic, is, of course, a region of permanent heat-loss). IF the surface air temperatures continue on a high, and IF the ice loss continues, despite the cooler temperatures of the waters flowing into the Arctic, then I will certainly abandon my critique and accept that CO2 is the main candidate driving this recent peak.
Verity:
The questions were not rhetorical and I appreciate you answering the ones you did. Please respond to the items you left unanswered.
Peter Taylor:
Thanks for the info, I will check through the peer reviewed studies to see how many actually identify an influence from aerosols or other sources for the 1940 to 1970 cooling. I do not contend this was the only factor. If you have time, please provide some links to studies that support the very interesting information you posted.
I accept the criticism of the models used by the IPCC as the forecasts substantially understated the potential for arctic sea ice loss. These models are attempting to forecast complex processes that are not well understood. I doubt the creators of these models think they are perfect. Rather, the models appear to be a work in process that are constantly being altered and improved.
I also accept the position that factors other than warming from human additions of CO2 to the atmosphere are causing changes in the arctic. What I do not see is that the Russian study forms a sufficient basis to say that a rebound will occur.
Verity:
The very information you provide casts doubt on the stability of the 60 year cycle since the period of the LIA and MWP were not 60 year cycles. Relying on the relative short period and geographic limitations from the Russian data to forecast a future rebound does not appear supportable given other information which suggests the cycle is not stable. You do not appear to be applying the same level of skeptical challenge to the Russian conclusions as you have to other data that conflicts with your bias.
The 1940 to 1970 period of cooling appears to be the subject of multiple explanations, and given the complexity of climate, I would not expect the answer to be so simple as saying that any one single item such as human induced changes from sulphate levels were the only driving factor. There also appear to be additions due to volcanic activity and perhaps TSI reductions. While the information provided by the author of the link below is subject to some rather sharp analysis at this blog, at least he is proposing possible sources for the changes observed in this period.
http://tamino.wordpress.com/2010/08/23/antrhopogenic-global-cooling/
I can understand disagreeing with the certainty levels that Tamino attaches to the various forces listed and I concede there may be other factors at work that he has not identified. The point is that the global cooling of 1940 to 1970 did not happen by magic. The cooling occurred due to changes in the physical forces being applied to the climate system.
If you want to assert that arctic ice will rebound, show me the forces that will cause the rebound and why these forces are going to be able to override the increase in radiative forcing by CO2 and warming due to loss of albedo due to diminished ice cover. If you are going to rely on diminished heat inflow from ocean currents, then explain why this will occur as TSI increases from its current low point. There may be some loss on the Pacific side as the Pacific switches from el nino to la nina in 2011, but this would not appear to be a sustained change as it is likely that el nino will return. These two forces appear to be a net zero at best and may be a net positive forcing as el nino patterns are shifting and becoming more intense
Perhaps you can identify some long term change in the Atlantic ocean currents, which appear to provide most of the heat inflow from ocean currents to the arctic, due to a shift in thermohaline circulation.
Lets stick with identifying the physical forces for the rebound rather than just wishing it will occur.
Peter Taylor:
Are you suggesting aerosols have no climate impact or only that they may not be the sole source that had an impact on the temperature change from 1940 to 1970.
The focus of my commentary should be the reliability of the prediction in the article left by Verity Jones of an arctic ice rebound based on the cited book and the historical data cited in the book. I am not refuting the data, only the conclusions drawn from the data. I apoligize to the extent I have gone off topic.
There are many forces affecting the current decline in Arctic ice.
When these individual forces are scrutinized and compared to historical levels, the book prediction of a rebound appears unreliable. The book did not identify the physical forces that are generating the observed 60 year cycle, and therefore does not offer much on which to base a rebound prediction.
Regardless of the impact of aerosols on the data collected in the book, changes in aerosols since 1970 appear to be having a net warming effect on the Arctic (according to peer reviewed studies).
Decreasing concentrations of sulphate aerosols and increasing concentrations of black carbon have substantially contributed to rapid Arctic warming during the past three decades. These are additional sources of arctic warming that will have to be overcome or changed before the Arctic ice extent can rebound, as predicted in the article above, can occur.
NASA GISS suggests aerosols play a large role in Arctic warming
This information was noted by Anthony Watts at:
http://wattsupwiththat.com/2009/04/09/nasa-giss-suggests-aerosols-play-a-large-role-in-arctic-warming/
The above posting and many of the comments about the study were generally positive, particularly by those seeking to deny any impact for CO2 induced warming.
There does appear to be some uncertainty in the role of aerosols as another article includes the following when reporting about the study:
“This is an important model study, raising lots of great questions that will need to be investigated with field research,” said Loretta Mickley, an atmospheric chemist from Harvard University, Cambridge, Mass. who was not directly involved in the research. Understanding how aerosols behave in the atmosphere is still very much a work-in-progress, she noted, and every model needs to be compared rigorously to real life observations. But the science behind Shindell’s results should be taken seriously. [Info on this Drew Shindell is at http://www.giss.nasa.gov/staff/dshindell/ which includes references to other peer reviewed papers by Drew Shindell]
“It appears that aerosols have quite a powerful effect on climate, but there’s still a lot more that we need to sort out,” said Shindell.
http://www.nasa.gov/topics/earth/features/warming_aerosols_prt.htm
Another source reporting on the study, which appears to rely on a model, states:
“A new study, led by climate scientist Drew Shindell of the NASA Goddard Institute for Space Studies, New York, used a coupled ocean-atmosphere model to investigate how sensitive different regional climates are to changes in levels of carbon dioxide, ozone, and aerosols.
The researchers found that the mid and high latitudes are especially responsive to changes in the level of aerosols. Indeed, the model suggests aerosols likely account for 45 percent or more of the warming that has occurred in the Arctic during the last three decades. The results were published in the April issue of Nature Geoscience.”
http://www.sciencedaily.com/releases/2009/04/090408164413.htm
The peer reviewed study is at:
Drew Shindell, Greg Faluvegi. Climate response to regional radiative forcing during the twentieth century. Nature Geoscience, 2009; 2 (4): 294 DOI: 10.1038/ngeo473
Abstract:
“Regional climate change can arise from three different effects: regional changes to the amount of radiative heating that reaches the Earth’s surface, an inhomogeneous response to globally uniform changes in radiative heating and variability without a specific forcing. The relative importance of these effects is not clear, particularly because neither the response to regional forcings nor the regional forcings themselves are well known for the twentieth century. Here we investigate the sensitivity of regional climate to changes in carbon dioxide, black carbon aerosols, sulphate aerosols and ozone in the tropics, mid-latitudes and polar regions, using a coupled ocean–atmosphere model. We find that mid- and high-latitude climate is quite sensitive to the location of the forcing. Using these relationships between forcing and response along with observations of twentieth century climate change, we reconstruct radiative forcing from aerosols in space and time. Our reconstructions broadly agree with historical emissions estimates, and can explain the differences between observed changes in Arctic temperatures and expectations from non-aerosol forcings plus unforced variability. We conclude that decreasing concentrations of sulphate aerosols and increasing concentrations of black carbon have substantially contributed to rapid Arctic warming during the past three decades.”
http://www.nature.com/ngeo/journal/v2/n4/full/ngeo473.html
A later study by the same Dr. Drew Shindell was also cited favorably on this blog
http://wattsupwiththat.com/2009/10/31/an-idea-i-can-get-behind-regulate-methane-first/
indicates that:
“Certain gases that cause warming are so closely linked with the production of aerosols that the emissions of one type of pollutant can indirectly affect the quantity of the other. And for two key gases that cause warming, these so-called “gas-aerosol interactions” can amplify their impact.
“We’ve known for years that methane and carbon monoxide have a warming effect,” said Drew Shindell, a climate scientist at the NASA Goddard Institute for Space Studies (GISS) in New York and lead author of a study published this week in Science. “But our new findings suggest these gases have a significantly more powerful warming impact than previously thought.”
http://www.sciencedaily.com /releases/2009/10/091030100020.htm
NASA/Goddard Space Flight Center (2009, October 31). Interactions With Aerosols Boost Warming Potential Of Some Gases.
Please provide peer reviewed studies which come to a conclusion that the trend with respect to current aerosol levels will lead to a decline in Arctic temperature.
The article below may be a good start, but the article did not connect the observed “visibility” change in the atmosphere to changes in temperature levels. The global dimming observed may be reducing the warming impact from other sources, but does not appear to have helped the Arctic ice extent. Making the air in the U.S. as polluted as it is in China does not represent a sound policy for assisting a rebound of Arctic ice.
Kaicun Wang. Robert E. Dickinson, Shunlin Liang. Clear Sky Visibility Has Decreased over Land Globally from 1973 to 2007. Science, March 13, 2009
http://www.sciencedaily.com/releases/2009/03/090312140850.htm
I am also looking at the possible impact of increasing cloudiness in the arctic as being a source of a rebound, but so far, the clouds appear to generate more warming since they do not have a significant impact on albedo compared to summer ice and in winter the clouds have a significant warming affect:
Abstract:
“The simulation of Arctic cloud cover and the sensitivity of Arctic climate to cloud changes are investigated using an atmosphere–mixed-layer ocean GCM (GENESIS2). The model is run with and without changes in three-dimensional cloud fraction under 2 × CO2 radiative forcing. This model was chosen in part because of its relatively successful representation of modern Arctic cloud cover, a trait attributable to the parameterized treatment of mixed-phase microphysics. Simulated modern Arctic cloud fraction is insensitive to model biases in surface boundary conditions (SSTs and sea ice distribution), but the modeled Arctic climate is sensitive to high-frequency cloud variability. When forced with increased CO2 the model generally simulates more (less) vertically integrated cloudiness in high (low) latitudes. In the simulation without cloud feedbacks, cloud fraction is fixed at its modern control value at all grid points and all levels while CO2 is doubled. Compared with this fixed-cloud experiment, the simulated cloud changes enhance greenhouse warming at all latitudes, accounting for one-third of the global warming signal. This positive feedback is most pronounced in the Arctic, where approximately 40% of the warming is due to cloud changes. The strong cloud feedback in the Arctic is caused not only by local processes but also by cloud changes in lower latitudes, where positive top-of-the-atmosphere cloud radiative forcing anomalies are larger. The extra radiative energy gained in lower latitudes is transported dynamically to the Arctic via moist static energy flux convergence. The results presented here demonstrate the importance of remote impacts from low and midlatitudes for Arctic climate change.”
The Impact of Cloud Feedbacks on Arctic Climate under Greenhouse Forcing by
Steve Vavrus
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0442(2004)017%3C0603%3ATIOCFO%3E2.0.CO%3B2
Will Crump:
You asked about the work on the cooling period. It does, of course, correspond with the Pacific Decadal Oscillation, as many have pointed out – and although that is an alternation of sea level pressure states, as is the Arctic Oscillation, and temperature changes follow, these temperature changes can only really be due to differential cloud cover and/or natural aerosols affecting insolation at the sea or land surface.
I was alerted to the nature of the global cooling trough by three key papers in 2005 Science:
Pinker R.T., B. Zhang and E.G. Dutton (2005) Do satellites detect trends in surface solar radiation? Science 308 p850-854
Wielicki B.A. et al., (2005) Changes in earth’s albedo measured by satellite Science 308 , 825
Wild M. et al., (2005) From dimming to brightening: decadal changes in solar radiation at the Earth’s surface Science 308, 847-850
These papers convinced me that the IPCC models using anthropogenic aerosols as explanation for the global trough were wrong. That sulphate pollution was too localised and the pattern was prevalent in unpolluted zones. If you hunt through the IPCC working group reports, you will find they have agreed that in 2007, but they don’t say what it means for the model hindcasts! (I don’t have the reference for that page – sorry, I must look it up!).
It is clear from these papers that cloud cover and a more transparent atmosphere were the causes of the shift from dimming to brightening in the early 1980s, but prior to that there were no globalised surface radiation budget data and so one must assume the transition from 1940 to cooling was also a shift in cloud and atmospheric transparency.
On the wider Arctic dynamic – I have a chapter in ‘Chill’ which gives an extensive bibliography – I find the oceanography gets little press, and there is much from papers that report nothing unusual on ice-mass, surface melting and surface temperatures as of now compared to 1930s and 1940s in Greenland.
The periodicity of the Arctic Oscillation may not be regular – we have little direct data, but I would have thought that there would be somewhere some spectral analysis of the Greenland GISP cores over the Holocene period. The warm periods of MWP and Roman, and at 3000BP, 5000BP (not as pronounced) and ca 8000BP show more of a Fibonacci series than would be sensible to average (8,5,3,2,1) with gradually falling peaks – all the previous Greenland peaks are above the current warm period. This pattern is a subset of what you can see in the ice-age patterns around 30-50,000 years BP, where a cycle repeats with 4-5 peaks per 10,000 years and again with a pattern of the peaks starting out broad and getting narrower in a quasi Fibonacci pattern. An averaging of 2000 years per cycle would obscure the pattern.
If you mail me: peter.taylor(at)ethos-uk.com I can send you the relevant graphics from my book and some more that are more recent.