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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Theo Goodwin writes,
“If you need to send us to an article, you are presuming to assign homework.”
Theo, this thread is titled “New paleo reconstruction shows warmer periods in Alaska over the past 3000 years.” Without the bother of doing homework, what do you reckon that it’s about?
It is very hard being a realist in such an emotion charged atmosphere, but that is what I am trying to do. What we actually do know is as follows:
• It is difficult and probably impossible to ever get agreement as to whether certain paleontological reconstructions are comparable with modern global indexes. Both in reality have grave questions hanging over them. The paleontological evidence is fragmentary, scattered, and may not be representative, while the statistical methods used have been severely criticised. The modern indexes are based on less than perfect data and the validity of the methods of collection, summarisation and processing are yet to receive universal acceptance. (Others have described at least some of these problems elsewhere, in great detail.)
• There are copious historical documents and artistic representations that lead us to suppose that at times during the last 2,000 years, contemporaries regarded the weather in the northern hemisphere as particularly warm, calm and pleasant, while at other times as particularly cold, stormy and unpleasant. The southern hemisphere is less well documented.
• There is a growing body of evidence to suggest that the climate in the two halves is but poorly inter-connected.
• There are some who believe that the modern instrumental record strongly suggests that human emissions of the trace gas, carbon dioxide, are causing the temperature to rise in an unprecedented manner, which will bring catastrophe to the earth. Others claim that what the record shows is that such minor changes that have been recorded to date, are merely the result of normal fluctuations, that have been experienced many times before and that we may well have now entered the start of a new, much colder phase of the cycle, which may continue for a number of decades.
From all the above, it is a little difficult to see that most urgent and important task for the people of the earth, is to embark on a hugely costly experiment that could have unintended negative consequences.
I strongly recommend that Gneiss be banned from this site. His behavior is typical of the Pit Bulls at the Guardian website. If those people are permitted on this website then they will own it and destroy it.
Of course, it was wonderful of Anthony to publish an addendum but that was unnecessary for most who visit this website. Anthony addressed fully all of Gneiss’ criticisms but Gneiss could care less. Gneiss made no reasonable responses to Anthony.
Talk about AGW peer-pressure,
“Despite their importance for evaluating anthropogenic climatic change, quantitative temperature reconstructions of the Holocene remain scarce from northern high-latitude regions.”
So they set out to create a reconstruction to be used for this purpose and then state this (likely were forced to inject this by a team reviewer),
“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.”
They then go on to make excuses for why their results don’t match the “settled science”. These papers are not objective anymore, they have become injected without all sorts of conflicting language as the authors give into peer-pressure from reviewers and editors forcing AGW “excuse” language into these papers. Now legions of alarmists can quote that paragraph ad nauseum. I don’t even understand why the paper compares their results to other subjectively chosen papers? Can these “scientists” not do an objective analysis of the data no matter the results? Pathetic.
Heh. One of my little grammarnazi hobby-horses is the varieties of “p****-ing of curiosity”. The above quote about organic deposits by glaciers into the ocean uses:
“His curiosity peeked, in spring 2009,”. I checked the link. It uses “peaked”. So, the quoter obviously corrected it.
Except, of course, that the correct word is “piqued”.
I even once saw “peked”. I presume a dog was involved …
Oops. I guess my last (humorous) posting ended up in the bitbucket. I claimed the title of “grammarnatsi” (spelled with a z), and I guess that got snagged. Mod, please feel free to use the phonetic equivalent above, or “grammarnasty”.
😉
Subscribe post.
Poptech says:
January 29, 2011 at 7:32 pm
Talk about AGW peer-pressure,
“Despite their importance for evaluating anthropogenic climatic change, quantitative temperature reconstructions of the Holocene remain scarce from northern high-latitude regions.”
So they set out to create a reconstruction to be used for this purpose and then state this (likely were forced to inject this by a team reviewer),
“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.”
They then go on to make excuses for why their results don’t match the “settled science”. These papers are not objective anymore, they have become injected without all sorts of conflicting language as the authors give into peer-pressure from reviewers and editors forcing AGW “excuse” language into these papers. Now legions of alarmists can quote that paragraph ad nauseum. I don’t even understand why the paper compares their results to other subjectively chosen papers? Can these “scientists” not do an objective analysis of the data no matter the results? Pathetic.
It seems to me that you are ignorant of how science is done. A single finding that is unsupported by other scientific work must be regarded with skepticism. The disclaimer is not the result of any sinister coercion by forces pushing AGW, but the result of good scientific training.
The fact is that other studies of lake sediments in the Arctic, using different temperature proxies come to a different conclusion regarding the modern temperatures versus the MWP, as I have pointed out in my above post.
http://www.pages-igbp.org/products/newsletters/2009-1/special%20section/science%20highlights/Kaufman_2009-1%2810-11%29.pdf
High-resolution records
Of the new proxy records, six are resolved at sub-decadal to annual scale, including four based on varve thicknesses and two on biogenic-silica content (Fig. 2). They were calibrated using instrumental climate records to develop regression models to infer numerical values of past summer temperature downcore. The temperature variation for these records averages ± 0.73°C (1σ). Stacking the records by binning the data into 50-year intervals, normalizing each to a mean of zero and a variance of 1σ, then averaging the values for each bin reveals a coherent structure to the time series. Most striking is the most recent half-century, which exhibits the single highest average normalized temperature values and a shift to higher temperatures that is twice as large as any other consecutive interval during the last 2 kyr.
This is why the authors of the midge study are cautious about taking their results as definitive.
Gneiss says:
January 29, 2011 at 5:39 pm
“There is no censorship of views here”
Of course there is, Smokey, do you honestly not know that?
I can’t wait for the follow-up on this one. Probably some radical new definition of the word “views” that we all hadn’t previously been aware of. Or “censorship.”
Or “honestly,” as like as not.
PS Yes Gneiss I read it, but maybe you could help me with some of the *big* words.
Can anyone name a relevant difference between Mann and Clegg? Yes, that’s a trick question.
Jim D says:
January 29, 2011 at 10:30 am
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.
===========================================================
My quick search came up with this ..http://www.john-daly.com/alaska/composite.gif
.. which shows virtually no trend since 1980.
The point is that the peaks and troughs which show up in annual and decadal values disappear when looking at centurial and millennial running averages as in the graphs above.
That is unless of course you have the extraordinary prescient powers claimed by all CAGW zealots.
Gneiss says (4:02 pm):
“As for persuading any of the regulars here of what most scientists believe, that AGW is real, I have no illusions about the prospects for that.”
On this blog you will find people who think that CO2 does little harm and is actually good for the planet (plants grow better, that is true). And you will also find people, like me, who Anthony views as “lukewarmers.” You will find links to blogs of lukewarmers, such as Roger Pielke, Jr. I think CO2 does warm the climate, it is real. But that doesn’t mean much if the temperature increases are relatively minor and probably cause little net harm at current rates. That is where the issues are to me — what harm can we reasonably expect from current rates of warming?
Slight change of subject: I wonder if the reason that the Hockey Team chose to look only at the past 1,000 years — and still were wrong that there was no Medieval Warm Period or Little Ice Age — is that if they had looked at longer time periods, they would have run into the innumerable papers showing that the Holocene Optimum was considerably warmer than today. That is why we find articles, of which the midge proxy article is one, showing that the Arctic was considerably warmer 6,000 to 8,000 years ago. Greenland was much warmer then, and as shown in earlier entries to this blog, there was a period of about 1,000 years where in the warm part of summer, there was very little ice from the North Pole to the north coast of Greenland.
Thus, today’s warmth is not unprecedented in our current interglacial. Of course, it isn’t unprecedented in the last 1,000 years either. It is unprecedented in the thermometer record, and since the Little Ice Age, however.
I’d be willing to change my current outlook if I were persuaded that things were soon going to be dire. But our current rate of warming is about 1.7 degrees per century, at the low end of the IPCC projection, based on satellite records, and that is due not just to CO2 increases, but to increases in ozone, black carbon, and methane, and by decreases in sulfate. If we work on these last 4 — much easier to deal with than CO2 — then CO2’s effects may by themselves be more in the nature of 1 degree per C. If that is correct, I don’t see the panic.
Christopher Hanley, and I could point to this one for 1970-2000.
http://climate.gi.alaska.edu/ClimTrends/30year/30yr.html
I think Gneiss has chosen a very appropriate pen name for his/her comments here.
Jim D (9.00 pm), it’s a trivial matter, but your original claim that Alaskan summers had warmed by about 0.5 degrees (C or F?) since 1980 does not seem to be confirmed by your link and the trends since 1971 are mainly due to a T leap in most locations around 1975-76.
My link showed a similar T plunge around 1940 which in both cases would suggest a climate shift of some sort.
But to reiterate, these leaps and bounds at the annual and decadal scale do not figure at the centurial or millennial scale as per the graphs above.
Anthony….As comforting it is to know the articles implications for the big picture….the AGW crowd now KNOW that AGW is real, ad infinitum, through to the murky past of human existence.
They said it first….the debate is over….the only thing remaining is providing those that vote in a representative government the education they need to reject this socialist tripe.
I’m actually very impressed with man in general in that they can be perceived as weilding such ominous powers to end ice ages….etc.
Quite an industrious lot I’d say……which is, of course, not appreciated by the AGW’s.
So to put me out of my misery, could someone tack the recently measured temperature data onto the end of the graph so we can see how the current period in Alaska actually corresponds to the LIA & RWP?
I imagine its not easy, and maybe big error bars will arise, but just something to give me an idea of how current temperatures in Alaska compare with historic ones…..
John Brookes says:
January 29, 2011 at 10:44 pm
So to put me out of my misery, could someone tack the recently measured temperature data onto the end of the graph so we can see how the current period in Alaska actually corresponds to the LIA & RWP?
===========================================================
It’s not regarded as kosher to tack the instrumental record smoothed to say a 10 year running mean on the end of a proxy series, let alone one which consists of what looks like at least 200 year smoothing.
You not see that?
Yep, you could. Then you could point to 1910-1940, and then to 1850-1880. With warming amounts and slopes indistinguishable from 1970-2000. Well before the ’40s spike/growth in CO2 emissions.
But only if you were [snip – watch the ad homs ~jove,. mod]
Gneiss:
‘Smokey, I gather that you haven’t read any of this research either? Mann et al. show (and others have replicated) that omitting the Tiljander series makes little difference to their results — except that, ironically, the Medieval Warm period looks a little less warm without Tiljander. In any event, they published graphs that show it both ways.”
you know full well that this is neither the FULL story nor an accurate rendition. Given the systematic effects of using any linear effects model with temperature proxies all you need is one ingredient with a hockey stick shape to create a hockey stick. Tiljander or any one of the bristlecone/yamal/etc will do. There is a known reduction of variance with all the methods so feed any of those methods a hockey stick proxy and noise and you get a HS out.
Of course the folks here will tell you that I am a warmer, but even I can’t swallow the results of Mann ( or many of these proxy studies). As gavin said they are scientifically uninteresting
Poptech says:
January 29, 2011 at 7:32 pm
Talk about AGW peer-pressure,…
They then go on to make excuses for why their results don’t match the “settled science”. These papers are not objective anymore, they have become injected without all sorts of conflicting language as the authors give into peer-pressure from reviewers and editors forcing AGW “excuse” language into these papers. Now legions of alarmists can quote that paragraph ad nauseum. I don’t even understand why the paper compares their results to other subjectively chosen papers? Can these “scientists” not do an objective analysis of the data no matter the results? Pathetic.
=====
Your harsh critique of the language used by the authors is unwarranted. Such caution about results, and comparison with other work in the field is common and standard practise in science. Perhaps it is an unfamiliarity with scientific papers, but I can provide numerous example of exactly the same sort of language in research papers in many other fields of science unrelated to AGW.
To present research without putting it in the context of other findings in the same field WOULD be wrong and again is standard practice in scientific research papers.
The problem the researchers have in matching past records to the present conditions is in part due to acid rain which has changed the ecology of the lake in recent decades. Many insect larvae are affected by the ph of the lake, so present midge populations are not comparable with past abundances. This makes their caveat of –
““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.”
rational and NOT evidence of unreasonable peer pressure and lack of integrity.
To describe it as such is…. pathetique
Perhaps an example of why caveats are reasonable on this issue. The graph above shows the peak of the MWP at ~1200AD with a slow rise before so that temperatures around a thousand years ago lower. But many records of the MWP, including some in the northern hemisphere, show a peak at or before 1000 BP and much cooler temperatures by 1200AD ~800 BP. This link has a nice graph with many measures of the MWP from around the globe. It can be fun game trying to find two where the peaks match…http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html
Either the dating on many of these is out by centuries, and the peaks are synchronous, or more likely, the MWP was a transient local phenomena which affected different regions in different decades.
Christopher Hanley says:
It’s not regarded as kosher to tack the instrumental record smoothed to say a 10 year running mean on the end of a proxy series, let alone one which consists of what looks like at least 200 year smoothing.
OK, all I want to know is how the temperature at the end of the proxy record in the paper compares with the current temperature (or the average of the last 10, 20 or 30 years, whatever). If I was smarter, I’d look at the paper and understand how they converted the proxy to a temperature (and how they estimate the validity of this conversion), so if you feel like explaining that as well, please do.
hell_is_like_newark
The answer is, of course, yes.
CO2Science has been tracking it for years.
http://www.co2science.org/ , about mid way down the page.
Or here is a direct link.
http://www.co2science.org/data/mwp/mwpp.php
And Anthony has their page on his role listing.
In answer to John Brookes, I looked for current average surface temperatures for that part of Alaska in July and found it is 58-62 F (near 15 C on that scale). For some, 30 years of such temperatures is not long enough to be significant yet, but I suspect it is only going to get warmer.
John Brookes says:
“OK, all I want to know is how the temperature at the end of the proxy record in the paper compares with the current temperature (or the average of the last 10, 20 or 30 years, whatever). ”
The paper says – ” 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).
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).
If you look up the recent July temperatures at Gulkana Airport since 2000 only two years have been below the 13.72 deg C of the 68-72 last sample period; and the average since is ~ 14.4 deg C, or well off the top of the graph and far above the peak shown for the MWP.
The problem in Mann ’08 was not that he later corrected his errors. The problem was that he knew before he published that he was using a corrupted proxy. He could have withdrawn his paper, but he chose to let it be hand-waved past his tame peer review referees, and be published.
Would an honest mann do that? No.