For those worried about tundra melt and methane outgassing, this study might dampen those worries a bit. A new peer-reviewed study by Clegg et al. demonstrates that modern global warming is significantly less than the global warming experienced in the higher latitudes, specifically Alaska, during the summers of the last 3,000 years. It demonstrates that the Current Warm Period (CWP) is not unprecedented, at least for Alaska. The authors suggest a tie in to solar variability.
From CO2 science:
What was done
The authors conducted a high-resolution analysis of midge assemblages found in the sediments of Moose Lake (61°22.45’N, 143°35.93’W) in the Wrangell-St. Elias National Park and Preserve of south-central Alaska (USA), based on data obtained from cores removed from the lake bottom in the summer of AD 2000 and a midge-to-temperature transfer function that yielded mean July temperatures (TJuly) for the past six thousand years.
What was learned
The results of the study are portrayed in the accompanying figure, where it can be seen, in the words of Clegg et al., that “a piecewise linear regression analysis identifies a significant change point at ca 4000 years before present (cal BP),” with “a decreasing trend after this point.” And from 2500 cal BP to the present, there is a clear multi-centennial oscillation about the declining trend line, with its peaks and valleys defining the temporal locations of the Roman Warm Period, the Dark Ages Cold Period, the Medieval Warm Period, the Little Ice Age — during which the coldest temperatures of the entire interglacial or Holocene were reached — and, finally, the start of the Current Warm Period, which is still not expressed to any significant degree compared to the Medieval and Roman Warm Periods.
C3 Headlines provided an annotated and reversed graph which you can see below:
The paper title is published in Quaternary Science Reviews
Here’s the abstract:
Six millennia of summer temperature variation based on midge analysis of lake sediments from Alaska
Benjamin F. Clegg, Gina H. Clarke, Melissa L. Chipman, Michael Chou, Ian R. Walker, Willy Tinnere and Feng Sheng Hu
Abstract
Despite their importance for evaluating anthropogenic climatic change, quantitative temperature reconstructions of the Holocene remain scarce from northern high-latitude regions. We conducted high-resolution midge analysis on the sediments of the past 6000 years from a lake in south-central Alaska. Results were used to estimate mean July air temperature (TJuly) variations on the basis of a midge temperature transfer function. The TJuly estimates from the near-surface samples are broadly consistent with instrumental and treering-based temperature data. Together with previous studies, these results suggest that midge assemblages are more sensitive to small shifts in summer temperature (
0.5 °C) than indicated by the typical error range of midge temperature transfer functions (1.5 °C). A piecewise linear regression analysis identifies a significant change point at ca 4000 years before present (cal BP) in our TJuly record, with a decreasing trend after this point. Episodic TJuly peaks (14.5 °C) between 5500 and 4200 cal BP and the subsequent climatic cooling may have resulted from decreasing summer insolation associated with the precessional cycle. Centennial-scale climatic cooling of up to 1 °C occurred around 4000, 3300, 1800–1300, 600, and 250 cal BP. These cooling events were more pronounced and lasted longer during the last two millennia than between 2000 and 4000 cal BP. Some of these events have counterparts in climatic records from elsewhere in Alaska and other regions of the Northern Hemisphere, including several roughly synchronous with known grand minima in solar irradiance. Over the past 2000 years, our TJuly record displays patterns similar to those inferred from a wide variety of temperature proxy indicators at other sites in Alaska, including fluctuations coeval with the Little Ice Age, the Medieval Climate Anomaly, and the First Millennial Cooling (centered around 1400 cal BP). To our knowledge, this study offers the first high-resolution, quantitative record of summer temperature variation that spans longer than the past 2000 years from the high-latitude regions around the North Pacific.
Here’s an excerpt from the conclusion:
Within the limit of chronological uncertainties, some (but not all) of these cooling events at Moose Lake coincide with periods of reduced solar irradiance, such as the solar minima centered on the middle and late LIA (250 and 100 cal BP), 1400 cal BP, and 3400 cal BP (Steinhilber et al., 2009).
Although the co-occurrence of solar minima with cooling during the LIA is well appreciated, the role of solar output in modulating surface temperature remains controversial, partially because the effect of solar activity changes on the surface energy budget is orders of magnitude lower than those of the drivers operating over shorter timescales (e.g., clouds or volcanism) (Damon and Peristykh, 2005). Nonetheless, a number of recent paleoclimate
studies have attributed decadal- to millennial-scale variation to fluctuating solar irradiance in Alaska (Hu et al., 2003; Wiles et al., 2004; Tinner et al., 2008) and elsewhere (Hegerl et al., 2003; Damon and Peristykh, 2005; Eichler et al., 2009). Thus the potential role of solar irradiance in high-latitude climate change remains an issue that warrants further research (MacDonald, 2010). Analysis of midge assemblages in lake-sediment cores
from other sites is necessary to verify our results from Moose Lake and assess the potential linkages of summer temperature variation to fluctuating solar output.
The full paper is available at the Willie Soon’s website at Harvard here (PDF)
Addendum:
Some commenters point out that I did not include this caveat from the paper:
The Moose Lake TJuly record is of limited value for assessing anthropogenic warming in the context of the long-term natural variability because of the relatively coarse temporal resolution and potential impacts of human activity on the lake chemistry. The youngest sample of the record spans the period of AD 1968-1972, falling within the cooler interval of the 20th-century in Alaska (Chapin et al., 2005).
And they have a point, I should have included this. So I’m rectifying that now. They also say:
The inferred TJuly from this sample (13.76 +/- 1.43 °C) compares favorably with the mean of instrumental
July temperatures of the same period (13.77 +/- 1.13 °C,
corrected for a dry adiabatic lapse rate of 9.80 °C per km) as
recorded at a nearby weather station (Gulkana Airport). The relatively coarse resolution of the Moose Lake midge record, along with the brevity of weather-station records from our study region (w50 years), precludes a further assessment of our midge-based TJuly estimates through comparison with instrumental climate data.
However, the midge TJuly estimates of the past 350 years (Fig. 4A) can be compared with treering temperature estimates of the same period from tree line sites in the Wrangell Mountains (Davi et al., 2003; Fig. 4B). In general, the midge temperature inferences parallel the treering temperature patterns. For example, the two records exhibit similar magnitudes of climatic warming after the Little Ice Age (LIA) and both capture low temperatures corresponding to the middle and late phases of the LIA, which also coincide with local advances in valley glaciers within the Wrangell Mountains (Wiles et al., 2004). However, the specific peaks and troughs do not always match between the two records, which is expected given the chronological uncertainties associated with our 210Pb ages and with the age-depth model for samples older than 64 cal BP.
These results contribute to a growing body of evidence
demonstrating the utility of midge assemblages for reconstruction of relatively small TJuly variation on both historic and Holocene timescales (e.g., Heiri et al., 2003; Larocque and Hall, 2003). Together, these studies indicate greater sensitivity of midge assemblages to TJuly variation than implied by reported error envelopes of midge temperature transfer functions.
Clegg et al thinks that the TJuly agrees with a local instrument record, some tree-ring study, and suggest TJuly signal is greater than the error bands. However, this brings up an interesting point.
In a similar midge-paleo study covered on WUWT (Yarrow et al 2009, PNAS, full PDF here, CU-Boulder press release here) the authors of that study say in the press release that:
…changes seen in the sediment cores since about 1950 indicate expected climate cooling is being overridden by human activity like greenhouse gas emissions.
So we have one study, Clegg et al saying that this midge-paleo is too coarse to use for AGW signal determinations, and another similar study Yarrow et al saying midge-paleo (with others) does have enough resolution and it shows a modern impact of humans emitted GHG. Quite the contradiction.
In the Yarrow et al Baffin Island study, they do in fact look at more recent core data than the Clegg et al Alaska lake study. In reading the Clegg et al study, they say:
The youngest sample of the Moose Lake midge record (from 3.0 to 3.5 cm core depth; we did not have adequate amount of sediment from 0 to 3 cm for midge analysis) encompasses sediment deposition of AD 1968-1972.
Yet, in the Yarrow study they apparently did have enough sediment to make a determination and then claim that it shows unprecedented warming and human influence. Interestingly though, they cite a “statistical uncertainty of 2.2 °C”
As with any transfer function, chironomid-inferred temperatures contain some statistical uncertainty (14, 34). Although absolute temperature values have a statistical uncertainty of 2.2 °C, reconstructed trends in past temperature at this site are likely robust because the amplitude of these trends exceeds the statistical uncertainty of the model; furthermore, these trends are supported by many other proxies from the region (36).
So they also compared to other proxies. I find it odd though that Yarrow says this in the CU-Boulder press release here, emphasis mine:
But the cold-adapted midge species abruptly began declining in about 1950, matching their lowest abundances of the last 200,000 years. Two of the midge species adapted to the coldest temperatures have completely disappeared from the lake region, said Axford.
This seems to point to a sample problem for recent layers such as Clegg et al lament. I wonder what chironomid data Clegg et al had from 1972 forward and why they deemed it insufficient.
Apparently though, the lack of certain species wasn’t a problem for Yarrow et al, and they used that to bolster the claim that human caused warming was reflected by that species loss. I pointed to the fact that in Alaska and Canada, post World War II DDT use for mosquito control was the norm, so perhaps the lack of modern midges was a consequence of that DDT use in both cases. It is an uncertainty.
I’m reminded though of the Mann-Briffa Yamal tree ring debacle, where if that data didn’t fit near the present, you throw it out post 1960 and splice on the instrumental temperature record. Yarrow’s insistence that the cold species midge disappearance implies human caused warming is on par with the leap of “Mikes’ Nature trick”. Both ignore other potential influences.
While some commenters complain about the lack of Clegg et al data since 1972, the same posters IIRC did not complain about the proxy data truncation at 1960 and substitution of post 1960 instrumental data in Mann-Briffa’s studies.
While the lack of a useful sample post 1972 may simply be the lake biology, I think I’ll ask Clegg why they decided the post 1972 sample was insufficient and why Yarrow et al 2009 wasn’t referenced in the context of the modern midge data sample, and if they reply, and post a follow up note here.
I’ll close by pointing out Clegg et al’s closing sentence:
Analysis of midge assemblages in lake-sediment cores from other sites is necessary to verify our results from Moose Lake and assess the potential linkages of summer temperature variation to fluctuating solar output.
Replication is the basis of science, it is good to see them calling for that.
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Curious. In response to a few criticisms of your conclusions about this study, you bring up an unrelated issue (tree rings) from an unrelated geographic location (Siberia) from unrelated authors (Briffa et al) and blame it on an even more unrelated person (Mann).
And you get all the specifics wrong.
Smokescreen much?
REPLY: No the issue is that the midge paleo series ended in 1968-1972, so some people claim that negates the study in the modern. Mann truncated his data purposely in 1960, Briffa chose a subset of 12 trees from 34, and then they spliced different data onto the end of the series. Yet many take the Mann-Briffa series as gospel without question.
Both paleo series don’t go to 2010. One (Mann) is viewed as acceptable in suggesting the CWP is unprecedented, yet another also with a series that doesn’t go to 2010, and with splicing of a different dataset, is viewed as perfectly acceptable. Smokescreen much? – Anthony
I too will digest this study with a health dose of skepticism. More such studies are needed before it can be verified.
Still, as has been pointed out above, I am rather surprised that midges (called “black flies” in most of the north) have any value whatsoever.
I often get chills just thinking about the black clouds of the little devils that followed me all day, every day, during my summer in Labrador. During gusts of wind one could watch them struggle to keep up (and take a non buggy breath).
Scientists in the article linked below found that the Arctic was ice free from the North Pole to Greenland about 6 to 7 thousand years ago: “…the sea all the way to the North Pole was periodically ice free for a long time.”
Here is a link to the Science Daily article about the Arctic being largely ice free for a thousand years or so, from 6 to 7 thousand years ago:
http://www.sciencedaily.com/releases/2008/10/081020095850.htm
And here are some key paragraphs, including the heading “Open Sea:”
——–
Open sea
”The beach ridges which we have had dated to about 6000-7000 years ago were shaped by wave activity,” says Astrid Lyså. They are located at the mouth of Independence Fjord in North Greenland, on an open, flat plain facing directly onto the Arctic Ocean. Today, drift ice forms a continuous cover from the land here.
Astrid Lyså says that such old beach formations require that the sea all the way to the North Pole was periodically ice free for a long time.
”This stands in sharp contrast to the present-day situation where only ridges piled up by pack ice are being formed,” she says.
——-
I’m linking this in detail to show that this record shows similar substantial warmth, in the same time period, in a different part of the Arctic, as the study using midge records.
Forests that lived along the Gulf of Alaska between 2,500 to 7,000 years ago were subsequently covered by glaciers. The crushed organic matter is being expelled by the glaciers there today.
Again, for emphasis: 2,500 to 7,000 years ago coastal Gulf of Alaska was warm enough to grow forests. That is not the case today, since those ancient forests were subsequently blanketed by the glaciers that exist there now.
Neoglaciation has been occurring for the last 6,000+ years, ever since temperatures started to decline from the Holocene Climatic Optimum, entirely consistent with the decline in solar insolation due to Milankovitch cycles, which peaked ~10,000 years ago.
Unlike some if not many, I think that’s a big problem. Warmer Is Better. Fight the Ice.
Fred says:
January 29, 2011 at 7:44 am
did you miss this bit?
The Moose Lake TJuly record is of limited value for assessing
anthropogenic warming in the context of the long-term natural
variability because of the relatively coarse temporal resolution and
potential impacts of human activity on the lake chemistry. The
youngest sample of the record spans the period of AD 1968-1972,
falling within the cooler interval of the 20th-century in Alaska
(Chapin et al., 2005)
______
Indeed, since the bulk of the 20th century warming occurred after that date, but never the less, the study is important as they indicate the one more confirmation of a longer-term cycle at work that the study clearly shows, namely the so-called “Bond Events” which are most likely Holocene relatives of the glacial period Dansgaard-Oeschger events. These events, being roughly 1470 years apart and having occurred at regular intervals are certainly not anthropogenic in origin and seem to be related either to solar and/or ocean cycles. These events have the pattern of a rapid warming followed by a sudden cooling. Interestingly, we are exactly now due for such an event as the last one occurred approximately 1400 BP. The Bond events, whatever their origin, combined with longer term fluctuations in the PDO and AMO (especially when these ocean cycles line up to be both cold-cold or warm-warm at the same time) are the primary sources of my skepticism related AGW.
Oh for crying out loud, and people actually get paid for this.
I’m going to do a temp reconstruction using lemming pubic hair….
..why not
The Arctic has obviously been warmer, been “ice free” in the past, what does it matter anyway?
Do these bozo’s even realize we can’t control the climate, and if the climate was “stable” like they try to claim…..odds are, we wouldn’t even be here
Gneiss says:
January 29, 2011 at 8:34 am
Mann’s hockey stick, on the other hand, has held up to replication very well. Similar blades of steep recent warming have been seen now in scores of studies done by other research teams using many different kinds of data and methods. For the most recent example see Spielhagen et al. in Science Jan 28 2011:
=======================================================
lol, thanks for the chuckle. Mann’s hockey stick? Which incarnation? Held up very well? While also discussing two peer-reviewed study’s which refute Mann’s assertions? OK, maybe, only kinda, sorta, held up well…….. Anthony is obviously well versed on the subject and never needs any of my help, but dayum man. If you were half as familiar with the studies as you are seemingly stating, then you gotta know these things coming. Cherry picked treeometers. How many statisticians have to tell climatologists that they’re doing the math wrong? Replicating results? You don’t even have to be bothered by it, ………“MBH…a cardinal rule of statistical inference is that the method of analysis must be decided before looking at the data. The rules and strategy of analysis cannot be changed in order to obtain the desired result. Such a strategy carries no statistical integrity and cannot be used as a basis for drawing sound inferential conclusions.
That statement is all that needs to be said in regards to Mann’s hockey stick. That statement could be surrounded by meaningless word salad and drivel, but that statement stands on its own. You can reconstruct and replicate until the cows come home, in the end all you would be doing is replicating a predetermined outcome.
Not clear what point you are trying to make. You were the one that made a statement about current warming based on a comparison of a curve that stops ~1970. July warming in Alaska since then is about 0.5 to 2 deg C depending on where you are.
Seems to me that you should take that into account. As far as I can tell, this is what any of the multi-proxy reconstructions do – and I think that Mann et al’s latest goes up to 1990 as does McShane and Wyner. The one exception might be Loehle who doesn’t calibrate to modern temperatures at all.
How about you just edit the top post to make it clear that on it’s own a record only going to 1970 isn’t enough to say how the current warming relates to the past? – just like the authors of this paper said.
If you don’t set the standard on correcting errors, who will?
There’s only one conclusion that can be drawn from this, and that is there are more midges in the pipeline.
James Sexton says:
January 29, 2011 at 8:02 am
lol, beat me too it! While I’m as skeptical about bugometers as I am treeometers, I am a firm believer in “what’s good for the goose is good for the gander.” Anthony’s first post on this reveals this typical mindset. Its only proof if it shows warming, else error bars, cherry picking, and incredulity are invoked.
James, I agree with you on the lack of good proxies. However, there is a very reliable proxy that Metla researchers here in Finland have used: they have dug up tree fossils from lakes and areas above the present treeline in Lapland. Thus they conclude that MWP was 0,5 C warmer than present-day temps over there.
They do have a 7600 year tree-ring chronology but the samples are from a wide area and numbers are not large enough (in their opinion) for climatic reconstructions.
http://lustiag.pp.fi/
Hmm – My immediate thought was ‘what about predators?’ – For example, a good flock of swallows or swifts and it would be bye bye midges and therefore less appearance of midges in the sediment?
Alternatively, I suppose midges might suddenly die off if there was an unusual cold spell, forest fire, heavy rain, etc, etc?
I dunno, I know that palaeo stuff can be useful, but it still boils down to a ‘proxy’ and most of them can be affected by numerous other variables and not just temperature, so I prefer to take it all with a pinch of salt. Nature, as we all know – can play fearful tricks!
I see certain commenters are getting their knickers in a twist trying to belittle this paper.
For their benefit, the paper is just one small part of a very big jigsaw, of which most of the pieces have been lost.
This does not mean we should ignore it.
If the authors want verification they can do no better than look at the historical record
Claims of unprecdented warmth and abnormal melting of meltic arctic ice are unfounded if we look at history;
1 The following link describes the ancient cultures of the warmer arctic 5000 to 1000 years ago
http://en.wikipedia.org/wiki/User:Lithoderm/Inuit_culture
2 This relates to an Arctic culture thriving in warmer times 2000 years ago in Alaska
From the Eskimo Times Monday, Mar. 17, 1941
The corner of Alaska nearest Siberia was probably man’s first threshold to the Western Hemisphere. So for years archeologists have dug there for a clue to America’s prehistoric past. Until last year, all the finds were obviously Eskimo. Then Anthropologists Froelich G. Rainey of the University of Alaska and two collaborators struck the remains of a town, of inciedible size and mysterious culture. Last week in Natural History Professor Rainey, still somewhat amazed, described this lost Arctic city.
It lies at Ipiutak on Point Hope, a bleak sandspit in the Arctic Ocean, where no trees and little grass survive endless gales at 30° below zero. But where houses lay more than 2,000 years ago, underlying refuse makes grass and moss grow greener. The scientists could easily discern traces of long avenues and hundreds of dwelling sites. A mile long, a quarter-mile wide, this ruined city was perhaps as big as any in Alaska today (biggest: Juneau, pop. 5,700).
On the Arctic coast today an Eskimo village of even 250 folk can catch scarcely enough seals, whales, caribou to live on. What these ancient Alaskans ate is all the more puzzling because they seem to have lacked such Arctic weapons as the Eskimo harpoon.
Yet they had enough leisure to make many purely artistic objects, some of no recognizable use. Their carvings are vaguely akin to Eskimo work but so sophisticated and elaborate as to indicate a relation with some centre of advanced culture — perhaps Japan or southern Siberia —certainly older than the Aztec or Mayan.
3 This link leads to the Academy of science report of the same year regarding the Ipiutak culture described above
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1078291
4 This refers to the Vikings living in a warmer arctic culture 1000 years ago
People might be interested in reading a very interesting book about the Vikings called ‘The Viking world’. It is a very scholarly and highly referenced book running to some 700 pages and deals with all aspects of the Vikings. It is good because it does not have an axe to grind, but deals matter of factly with all aspects of Viking culture and exploration.
There is a large section on their initial exploration of Greenland, the subsequent establishment of their farms there, everyday life, how they gradually lost access to the outside world as the sea lanes closed through ice, a record of the last wedding held In Greenland and how trade dried up. It also deals with Vinland/Newfoundland and it seems that it was wild grapes that helped give the area its name, it being somewhat warmer than today.
This is one of a number of similar books that record our warmer and cooler past throughout the Northern Hermisphere. Al Gore wrote a good book in 1992 called ‘Earth in the Balance’ in which he explored the changing climate that devastated the civilisations in the Southern Hemishpere.
The book ‘The Viking World’ is Edited by Stefan Brink with Neil Price Published by Routledge ISBN 978 0 415 33315-3
I suggest you borrow it from the local library as it costs $250!
5 I wrote about a warmer arctic in the 1820’s in an article carried here
http://wattsupwiththat.com/2009/06/20/historic-variation-in-arctic-ice/
6 This refers to a warmer arctic 75 years ago recorded on Pathe newsreel by Bob Bartlett on the Morrisey during his journeys there in the 1920’s and 1930’s and reported in all the media.
http://boothbayharborshipyard.blogspot.com/2008/08/arctic-explorer-on-ways.html
Wednesday, 10th August 1932
The ship rolled heavily all night and continues to do so….
The glacier continues its disturbances. No real bergs break off but great sheets of ice slide down into the water and cause heavy seas. About noon, the entire face of the glacier, almost a mile in length and six or eight feet deep slid off with a roar and a rumble that must have been heard at some distance. We were on deck at the time for a preliminary report like a pistol shot had warned us what was coming. The Morrissey rolled until her boats at the davits almost scooped up the water and everything on board that was not firmly anchored in place crashed loose. But this was nothing to the pandemonium on shore. I watched it all through the glasses. The water receded leaving yards of beach bare and then returned with a terrific rush, bringing great chunks of ice with it. Up the beach it raced further and further, with the Eskimos fleeing before it. It covered all the carefully cherished piles of walrus meat, flowed across two of the tents with their contents, put out the fire over which the noonday meal for the sled drivers was being prepared, and stopped a matter of inches before it reached the pile of cement waiting to be taken up the mountain. Fortunately, in spite of heavy sea, which was running, the Captain had managed to be set shore this morning so he was there with them to help straighten out things and calm them down.”
7 Dr Arnd Bernaerts wrote of this 1919 to 1939 warming in this excellent free online book.
http://www.waterstones.com/waterstonesweb/products/arnd+bernaerts/arctic+heats+up/6976063/
The arctic has periodically warmed to greater amounts than today. A tiny reduction in ice extent since 1979 is of no consequence if you look at the historical record of this region
Tonyb
Southern hemisphere midge studies would be helpful; e.g., in NZ & the tip of S. America.
Anthony writes,
“No the issue is that the midge paleo series ended in 1968-1972, so some people claim that negates the study in the modern. ”
No, it negates the lead paragraph in your blog post, which is simply false. You keep offering to change the subject without admitting that.
Gneiss says:
January 29, 2011 at 8:34 am
Mann’s hockey stick, on the other hand, has held up to replication very well. Similar blades of steep recent warming have been seen now in scores of studies done by other research teams using many different kinds of data and methods. For the most recent example see Spielhagen et al. in Science Jan 28 2011:
=======================================================
Find me one that does not rely on bristlecones, upside down Tiljander sediments, dodgy statistical methods, failed verification statistics, obsolete data, cherry picked tree rings and has been independently reviewed by anyone outside the Hockey Team.
There are of course hundreds of quite unconnected and independent scientific studies which point to the existence of a strong MWP and LIA.
I am awaiting a statistician/scientist with broad expertise to do a meta-analysis of all temperature proxies that overlap in time and resolution, for example tree rings, midges, isotopes, foraminifers, vineyards, flora altitude advances, historic anecdotes, sailing ship bills of lading, etc.
Meta-analyses are very helpful, especially performed by a good statistician, as it gives increased reliability for a conclusion. Even exceptions help the meta-analyses, because of the statistical methods employed. From what I gathered over the past blogging era, the cold and warming ages of the past two or three millennia have been demonstrated over and over again, especially the recent highest temperatures occurring during the Roman and Medieval Warming periods.
Granted, they are a bear to do, but people have done these for years, for huge data bases, like epidemiology and medicine occurrences.
The way it works, is by using non-parametric statistical methods. For example, if I put my head outside and tell you, “it’s warm today”, you take this with a grain of salt. Maybe I have a fever. But if 95 out of 100 people surveyed say, “it’s warm today”, then the reliability goes up. The odds of 95 people having a fever is vanishingly small (but it could be an epidemic, so it is not impossible to have a systematic error happen, even in a meta-analysis!). This is simplistic, but that is what meta-anaylsis is all about.
A lot of times, meta-analyses uncover things like systematic biases, causality vs. correlation, etc. One caution is to use a “ruler” of the same length, so that the resolution is commensurate for the two or three millennial period in question. (in other words, do not include a proxy that has a 200,000 year resolution for the thousands year study period.)
I am not a statistician, but have used and relied upon statisticians and statistics in my science over the years, and am convinced of the usefulness.
Any statisticians to take up this gauntlet?
tony:
I was writing my response before yours was posted, but I think we are thinking along the same lines!
latitude says:
January 29, 2011 at 9:44 am
Oh for crying out loud, and people actually get paid for this.
I’m going to do a temp reconstruction using lemming pubic hair….
=======================================================
Well, you’ll certainly have many specimens to pick from. Everyone knows treeometers are way more valid than bugometers, well, only the ones from Alaska, I didn’t see these bug haters when discussing the ocean bugs by Greenland. Are alarmists biased against midges? Or just Alaskan midges? Bunch of haters the lot of ’em. I seem to recall a study where the warmistas liked midges, but I don’t think they were Alaskan midges.
@ur momisugly Gneiss
“No, it negates the lead paragraph in your blog post, which is simply false.”
“For those worried about tundra melt and methane outgassing, this study might dampen those worries a bit. A new peer-reviewed study by Clegg et al. demonstrates that modern global warming is significantly less than the global warming experienced in the higher latitudes, specifically Alaska, during the summers of the last 3,000 years. It demonstrates that the Current Warm Period (CWP) is not unprecedented, at least for Alaska. The authors suggest a tie in to solar variability.”
You’ll have to be a bit clearer for me, are you stating Anthony got his synopsis wrong or the study is wrong? Which part? Or do you simply disagree with the premise of “dampening worries”?
A quick search around the Web shows that southern Alaska summers have warmed about 0.5 degrees per decade since about 1980, or 2 degrees since 1950, which would make an interesting off-the-scale spike on the graphs displayed.
Here is a paleo abstract fro a paper dated 1971 covering the Holocene climatic optimum in Northwest Territories of Canada.
Present day tundra
do i see a trend? the warm periods are less warm than the previous warm periods and the cold periods are colder than the previous cold periods. could be a bad sign. cold is bad for humans and what we eat.
James Sexton writes,
“lol, thanks for the chuckle. Mann’s hockey stick? Which incarnation? Held up very well? While also discussing two peer-reviewed study’s which refute Mann’s assertions?”
Happy to have given you a chuckle. Let’s try for another:
After its false initial statement, Anthony’s post leads off with a graph. That graph is not from Clegg et al. but rather “adapted from” them, apparently by bloggers. There are a few changes between this WUWT/CO2S adaptation and the scientists’ Fig 4. For one thing, labels saying RWP, MWP, and CWP [turns out, it’s not really] have been added.
But the larger change is that 7 other squiggly lines have been erased. Those would clutter up the political message here because they show (as Clegg et al. carefully discuss) details of agreement and disagreement between the Moose Lake results and other Alaska temperature series (some of which, they admit, might be better), a pan-Arctic reconstruction, and two definitive Northern Hemisphere temperature reconstructions — those of Moberg et al. (2005), and Mann et al. (2008). All in the same graphic, in the same article by Clegg et al.
I guess that answers your “which incarnation” question; Mann 2008 is widely respected, a substantial improvement on Mann’s earlier chronology, as it should be. Some scientists prefer Moberg instead, but for the most part they get similar results. Both also show areas of agreement and disagreement with the Clegg et al. results.
Does nobody here (except Fred) actually look at these articles, before making confident statements about who they refute?
[Reply: You are welcome to submit your own article for publication here. Please do. ~dbs, mod.]
Gneiss says:
“Mann’s hockey stick, on the other hand, has held up to replication very well.”
No, it hasn’t. It was so thoroughly debunked that the IPCC no longer uses it. And they loved Mann’s hokey stick chart! It must torture them to no longer be able to put it front and center in their UN/IPCC global warming propaganda publications.
And Mann ’08 deliberately and knowingly used the corrupted Tiljander sediment proxy. Why? Because without Tiljander’s upside-down proxy, Mann couldn’t get the hockey stick shape he wanted. And the cowering journal referees didn’t dare to reject a Michael Mann paper. Only true believer CAGW Kool Aid drinkers would accept such an irretrievably damaged paper, knowing that Ms Tiljander had unwittingly used sediments that had been overturned by road construction equipment, putting the deeper sediment layers on top, and vice versa. Mann was notified of the corrupted Tiljander proxy before he published – and he published anyway. That is the act of a dishonest mann.
Note to Gneiss and Fred: Anthony has refuted your complaints. If you do not argue now against Mann’s truncations as strongly [or at all, for that matter] as you argued against this paper’s conclusions simply because they didn’t go right up until 2011, then your credibility is shot. Better get new screen names.