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.
The fluctuations in the reconstructed temperatures are smaller than the uncertainty in the reconstruction estimated by the root mean squared error of prediction. The reconstruction should therefore should be interpreted with caution.
REPLY:McIntyre and McKittrick and later McShane and Wyner pointed out similar caveats with the Mann hockey stick, yet for some people it is cautionless gospel.
Also, note the last sentence in their conclusion:
“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.”
Mann could have saved us all a lot of trouble if he’d been as cautious.
– Anthony
Clarify for me BP. I thought that some of the BP were just people trying to get away from BC and BP and BC zero were the same. This graph BP zero is 1990-2000.
If some one sees this graph 500 years from now how will they understanding the time perspective? Or did I misinterpret?
Methane outgasing is not too much of a problem for climate but the breakdown of methane requires oxygen. Previous anoxic events, that caused species extinction, have been thought to be caused by the oxidation of excess methane in the atmosphere.
I neve thought those pesky midges could ever serve any useful purpose. It just goes to show, we can all make false assumptions.
I wonder how the “Team” will discredit this one.
Please stop this cherry picking!
[please stop impersonating Paul Nurse, since I assume you are not really him. it is noted you use other names with this email address ~jove, mod]
Wow. If these results are confirmed it is dynamite. Just as many have been arguing the warmth is not unprecedented and the rate of warming is not unprecedented. In fact the current period could not look much more ordinary. So the climate scientists say there is no possible explanation for the current warming without CO2. I think they had better think again.
The correlation with the skeptics view of the real historical picture is amazing. If such a neat picture had come from the AGW camp I would have dismissed it as being too good to be true. I hope it is not in this case!
I would have liked to know the error bars on the temperature and also the temporal resolution but the sensitivity of 0.5C and the fact that successive summers can presumeably be counted suggests that both of these will be easily accurate enough for the purpose. Looks like great research.
“a midge-to-temperature transfer function that yielded mean July temperatures”
——————————————————————-
The only midge-to-temperature transfer function I am aware of is when the buggers bite you and your temperature goes up trying to swat them.
Even the cheesiest science fiction doesn’t strain credibility this much.
Telford is right. We should look with caution on any proxy reconstruction until it has been [truly] independently verified.
REPLY: Note the last sentence of the conclusion, the authors ask for independent verification – Anthony
@ johanna:
Funny how insects in sediments are credible when they imply 20th century warming is unique. Stop the presses 😉
http://www.colorado.edu/news/r/fa189a8186a324d8f62b5d55ba4b8969.html
An analysis of sediment cores indicates that biological and chemical changes occurring at a remote Arctic lake are unprecedented over the past 200,000 years and likely are the result of human-caused climate change, according to a new study led by the University of Colorado at Boulder.
The research team reconstructed past climate and environmental changes at the lake on Baffin Island using indicators that included algae, fossil insects and geochemistry preserved in sediment cores that extend back 200,000 years.
Anthony writes,
“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.”
I don’t see anything resembling this claim in their paper. For one thing, their chronology ends in 1968-72, a relatively cool period in Alaska, so it misses the signature run-up of modern global warming (since 1975). For another thing, the authors are cautious about possible affects of 20th-century human disturbances, notably dam building, on their Moose Lake site. Here’s what they actually say:
“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 [citations].”
REPLY: OK let’s say the 1930’s dust bowl warm spike (that it does catch) doesn’t matter either. That still leaves the question of how does the previous episodes of warmth happen without all our “modern” CO2. BTW where were your complaints about Mann and Briffa ending their series in the 1960’s?
Note the green line.
– Anthony
did you miss this bit?
REPLY: Did you miss this?
We covered it here earlier.
Funny how the high latitude midges can be usefull to prove human caused warming in one study and they can’t possibly in another. – Anthony
REPLY:McIntyre and McKittrick and later McShane and Wyner pointed out similar caveats with the Mann hockey stick, yet for some people it is cautionless gospel. – Anthony
I seem to be confused. Isn’t this saying that the very report you are praising has the very problem you are highlighting?
REPLY: No you aren’t confused. Neither am I. Dr. Mann et al is a different matter altogether. I’m glad you have come to the conclusion that Mann’s work suffers from the same sort of uncertainty problems. There may be hope for you yet.
As the authors point out, more lake studies are needed to confirm, and as more studies are done, the confidence may increase, or the study may be disproven. It would behoove Mann et al to take the same path, rejecting those 12 trees in Yamal as an insufficient and perhaps cherry picked sample (YAD061) and run the full Schweingruber set and see what they get. – Anthony
Jarmo says:
January 29, 2011 at 7:36 am
@ johanna:
Funny how insects in sediments are credible when they imply 20th century warming is unique. Stop the presses 😉
========================================================
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.
Well.. this blows more holes in the pro-AGW crowd’s claim that the RWP and MWP were “local phenomenons” for Europe or simply didn’t exist (the Yamal siberian tree study).
Has there been any significant research to show that the two warm periods also affected the Southern hemisphere as well?
This seems like an excellent study, and the authors are correct to point out similarities between their midge record and other records using other proxies.
One such study that they may mention in the body of their paper, but I didn’t see in the Abstract, is the record WUWT highlighted several months ago, showing that Greenland was considerably warmer about 6 to 8 thousand years ago, and has gotten cooler since, with peaks and valleys of temperatures at roughly the same time periods (LIA, MWP RWP) as in this record. The Greenland record used different proxies for temperatures, so now we have two roughly equivalent temperature records from two different parts of the Arctic using two different proxy indicators for temperatures. Thank goodness the proxies weren’t tree rings, or we would be back in the Mannian swamps….
One other thing to think about: if the gradual reduction in temperatures in the last 6 thousand years in the Arctic really is related less to the centuries-scale differences in the strength of the sun, but rather to a longer time period relationship of the earth’s orbit around and tilt in regard to the sun, then this may provide evidence for how the earth goes from interglacials such as we are in (the Holocene) into the next ice age.
And if that is the case, and this study and others provide some evidence that we are on the way to another ice age, then maybe we should consider the wacky argument that CO2 is keeping us out of the next ice age with a little more thought? I’m not yet on that bandwagon, but I’d like to see more paleoclimatologies think about it seriously.
On the other hand there is this new Science paper by Spielhagen et al. also linked from RC
http://climateprogress.org/2011/01/27/science-temperatures-atlantic-water-arctic-unprecedented-2000-years-linked-to-arctic-amplification-of-global-warming/
Basically the hockey stick is revived for the North Atlantic.
Anthony writes,
“McIntyre and McKittrick and later McShane and Wyner pointed out similar caveats with the Mann hockey stick, yet for some people it is cautionless gospel.”
McIntyre and McKittrick and later McShane and Wyner are cautionless gospel on many blogs. But they have not held up at all to scrutiny by scientists or statisticians who tried to replicate their results.
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:
“The Arctic is responding more rapidly to global warming than most other areas on our planet. Northward-flowing Atlantic Water is the major means of heat advection toward the Arctic and strongly affects the sea ice distribution. Records of its natural variability are critical for the understanding of feedback mechanisms and the future of the Arctic climate system, but continuous historical records reach back only ~150 years. Here, we present a multidecadal-scale record of ocean temperature variations during the past 2000 years, derived from marine sediments off Western Svalbard (79°N). We find that early–21st-century temperatures of Atlantic Water entering the Arctic Ocean are unprecedented over the past 2000 years and are presumably linked to the Arctic amplification of global warming. ”
When graphed, that looks much like a hockey stick — Fig. 3.
REPLY: The 64,000 dollar question: How does Mann/Briffa’s 12 trees from Yamal hold up when compared to the entire Schweingruber sample of 34?
The answer here and here.
– Anthony
I assume that more midges mean warmer temps and less midges mean cooler? Is that the train of thought? Over thousands of years midges don’t adapt/change? I thought some bugs mutated pretty rapidly. I think this part of the “research” is pretty skinny, but then I don’t know much about bugs. The midges we have here in WY seem to disappear when its windy and bother you when its calm. Not many around in the winter. Only see them near the water. Never see any in the dry flat lands or high in the mountains. Perhaps if they have been adapting then it has become even cooler over the period observed? Or maybe there were more birds and fish to eat them lately. Or how about changes in their environment other than temperature that caused less to hatch out/survive.
Probably a few too many variables involved here to make too much out of this. We are starting to sound like the AGW crowd, but then perhaps we need to fight fire with fire.
Paul Nurse:
Please stop this cherry picking!
Sir Paul Nurse – President of the Royal Society. I assume you are one and the same.
If so, I think your comment is a little pot and kettleish to say the very least. Your BBC2 Horizon effort this week was an utter disgrace to your profession. You should be ashamed of yourself for politicising science in the way you did. You referred to this blog as “denialist site”. You compared AGW skeptics to HIV deniers. You cherry picked 3 hours of discussion with James Dellingpole to create the editorial skew you required.
It was clear to me the only person in denial was you. Your efforts will embarrass the Royal Society in the coming years. You are a disgrace to you profession and your post.
There is evidence in the sunspot drawings & images that each Grand Minimum is capable of displaying different behavior.
Therefore, it is imperitive to current civilization to have a sober assessment of how closely the present Grand Minimum is driving the climate.
Is it a Lion or a Lamb?
Jim G says:
January 29, 2011 at 8:35 am
I assume that more midges mean warmer temps and less midges mean cooler?
——————-
The reconstruction isn’t based on abundance on midges, but on the relative proportions of different species. More midge remains from cold demanding species indicate cooler conditions, more remains from warm demanding species indicates warm conditions. The method is good when there are large temperature shifts (eg at the Younger Dryas-Holocene transition), it is less reliable when the temperature changes are relatively small.
I would so be going into caves and studying bat guano layers. And I know the damned stuff layers. It layered up in my attic. Midge population variation will affect bat population variation. Are there seasonal bats in our attic?
Anthony writes,
“OK let’s say the 193′s dust bowl warm spike (that it does catch) doesn’t matter either. That still leaves the question of how does the previous episodes of warmth happen without all our “modern” CO2.”
Wait, your “OK” there jumps past the fact that your lead paragraph for this post is simply false. The Clegg et al. paper does not demonstrate “that modern global warming is significantly less than the global warming experienced in the higher latitudes,” and the authors are clear as can be in explaining why not. Can you admit that mistake, before we change the subject?
REPLY: Refresh, I think you caught the comment in mid edit. I await your reply about Mann and 1960’s too, which suffers from the same problem you point out. – A
To Jim D (8:24 am), who says:
“On the other hand there is this new Science paper by Spielhagen et al. also linked from RC
http://climateprogress.org/2011/01/27/science-temperatures-atlantic-water-arctic-unprecedented-2000-years-linked-to-arctic-amplification-of-global-warming/
Basically the hockey stick is revived for the North Atlantic.”
Jim, I don’t have any reason to doubt the findings of the study showing that the Fram Strait has warmer waters than any time in the last 2,000 years. As with all new studies, including the one that is the subject of this particular post, it will need verification, but it may well end up being correct. We would also need to know if this is mostly a local effect, should it be verified.
A broader point remains, though: if we really are heading toward another ice ago, as this study and the Greenland ice core studies suggest (the Greenland ice cores showed that Greenland was substantially warmer around 6 to 8 thousand years ago than today, and follows the downward temperature trend with peaks around the RWP and MWP, as also found in this midge study), then is it harmful to have a warming trend to counter the downward temperature trend in the last 6,000 years or so?
We know from another journal article posted in WUWT a couple of months ago that the Arctic was substantially ice free in the summers, from about 6 to 8 thousand years ago — because researchers found deposition patterns on the coast that suggested large waves were regularly pounding the pebbles on the coast, leaving distinctive patterns that could only be made by waves. So the Arctic was substantially ice free in the warmest part of these summers, indicating a much warmer Arctic, in line with this midge study (and polar bears survived as well).
Again, I’m not on that bandwagon that says, we need to warm the earth to keep us out of another ice age. But we need paleoclimatologists to take this question seriously. When I look at these records which show so much more warmth about 6 yo 8 thousand years ago in the Arctic, it gives me pause about worrying too much about warming we see today. And if the Arctic was substantially ice free in parts of the summer for up to 2,000 years (6 to 8 thousand years ago), is it really a problem to have warm water from the Fram Strait be the specific mechanism for less Arctic sea ice?
Anthony will get on my case for suggesting that the Arctic sea ice might really be in a decline. Maybe things will reverse this coming decade, but to me the question isn’t whether there will be less Arctic sea ice going forward, it is whether such an eventuality is a disaster that needs costly and drastic action.
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.
@ 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.
Using biological anything seems risky. I guess if you had a lot of different biological proxies, then you could be more certain. But can’t a virus or bacterium come along and wipe out 1/3 or some number of the midges, like the black plague did humans? Other species have diseases too.
Perhaps this is stating the obvious, but this paper, like the others before it, and the discussion they generate to me lead directly to one very clear conclusion:
There is not enough data to conclude that the climate we are experiencing today is or is not influenced by CO2.
Trying to “bully” others into agreeing CO2 does or does not affect the climate seems to me quite futile.
The best thing about this paper, IMHO, is what Anthony has pointed out: rather than ask others to accept their findings the authors instead point out the need for verification. What a refreshing notion!
Smokey says:
January 29, 2011 at 10:45 am
You are right—Gneiss, Fred and Sir Paul Squarepants, or whoever, have been thoroughly outed and debunked, as far as I am concerned. I have passed over them for some time now. It would be wise to not waste your valuable blogging time dealing with them any longer, but get on with the good stuff, Smokey!
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.
________________________
Surely you mean wouldn’t it be interesting if the reconstructed temperature from midge data from recent times were plotted on the graph and matched the observed temperature increases? Of course you’re not suggesting using observed temperature data on the same chart with reconstructed temperature data, are you? I think we’ve seen that “trick” before!!!
Yes, KD, it is apparently against the rules to graft actual thermometer data onto the end of paleo reconstructions. My bad:-)
Instead of focusing on each proxy and rubbishing or lauding each, I think that the meta-analysis of proxies, as I mentioned before, is the way to go. What I would do with the data sets, is do a sigma relative curve for each proxy study. I would put all of the data in a column in an Excel spreadsheet or statistical software package. Then find the standard deviation. Then assign one, two or three sigmas to each point, with sign, either positively or negatively deviating from the mean.
Then I would graph each “sigma curve” as it oscillates around the mean, and plot it versus time period.
Then we would see if each proxy “tracks” with every other proxy. Then I would do a mean of the means to see if it correlates with a certain time. The derived temperature (absolute values of temperature—a derived number, anyway) in this scenario, would be irrelevant. We would only want to see which proxies validate other proxies with regard to the peaks and values versus time, and which proxies contradict the meta-analysis.
That way, we could see if the RWP, for example, was colder or warmer than the mean.
This suggestion is just an example of how to do a crude meta-analysis, using non-parametric tools.
A good statistician sets the appropriate “rules” in play before he gets the result. Let the evidence lead, rather than the bias.
Gneiss,
“New paleo reconstruction shows warmer periods in Alaska over the past 3000 years
Posted on January 29, 2011 by Anthony Watts
For those worried about tundra melt and methane out gassing, 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.”
Do the graphs show there were two warmer periods, RWP & MWP, with temperatures apparently higher than the CWP? Answer? Yes. Were these periods separated by DACP & LIA? Answer? Yes. Which means 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.” Ergo, the lead paragraph does not need editing, because it’s still not as warm as those two warm periods.
Actually, what you believe really does not matter in the overall scheme of things, because global temperatures will continue to decline to such a degree that even GISS will not be able to hide the decline. Such is life, man proposes & nature disposes. M’thinks you doth protest too much.
The graphs show well the (expected) decline in temps through the Neoglacial due to declining axial tilt.
Whether, as Jim D says, recent warming would push the line off the scale remains to be seen – we must always be wary of short term variation which may not be picked up in paleao-temperature data. But, of course, if the current warming trend continues ……
They aren’t measuring the number of midges, but the ratio of cold-adapted midges to warm-adapted midges.
bubbagyro :
See Osborn and Briffa 2006 in Science – I think they do what you suggest.
There is, sadly, no argument. Paul, Fred, and Gneiss arrived at this study with conclusion in hand, and frankly most of the responses to them are just from the other side. I think Anthony did respond to them with sufficient detail about this study, but it doesn’t matter because, as amusing as the response is, when the comparison is made to the flaws in Mann, the answer is that Mann is “accepted.”
It would have been nice if this subject wasn’t so political, because that seems to drive most of the research. But then, it was pretty much political from the start, and it’s difficult to navigate that particular maze.
These results are so preliminary that I don’t see what the CAGW proponents are getting twisted over anyway, clearly more work has to be done. The results to make *sense*, after a fashion (in context with a variety of geological and cultural records), which does not validate them but does suggest a need for further study.
Jim D says:
January 29, 2011 at 11:23 am
Yes, KD, it is apparently against the rules to graft actual thermometer data onto the end of paleo reconstructions. My bad:-)
_____________________________
In fact, yes it is. As a scientist, one typically doesn’t mix data in that fashion.
Using paleo data up to a given point in time and then switching to observed temperatures is analogous to this:
I want to know the average maximium speed in a given lap at Daytona. For years the best I can do during the race is to time a complete lap, calculating the average speed for the lap. Prior to the race I calibrate my average speed to maximum speed by having a driver, on the track alone, read his maximum speed while I record lap times. I build a simple correlation that says if I have a lap time of X the maximum speed was Y.
Then one day I have a radar gun to use. I now simply point the gun down the track at the fastest spot and record all of the speeds for every car and every lap.
Can you appreciate that the QUALITY of the data you get might be different and there is a very high probability that the maximum speeds DETERMINED using the two methods would be DIFFERENT, even if the maximum speeds were actually IDENTICAL?
Temperature history of Holocene and even earlier periods has a bearing on what might or might not happen today. Since it is their bearing on the state of current warming that all these measurements are supposed to elucidate, why don’t we forget all these proxies and take a direct look at what is known about the present warming. If we go back to the beginning of the twentieth century we notice that the first ten years of the century are not even warming – there is a ten year cooling period that starts off the century.
This is followed by a thirty year period of sustained warming from 1910 to 1940. That was when World War II started and temperatures dropped severely. The Finnish Winter War of 1939/40 was fought in the bitter cold of minus forty Celsius, German invaders in Russia were being frozen to death, and GIs fought their way from the Battle of the Bulge to the German frontier in the coldest winter West Europeans could remember. But if you look at the temperature curves from NASA, NOAA and the Met Office that entire period is shown as a giant warm spell! That is a laugh. They do show a temperature drop but that is after the war and they miss the warm dust bowl years in the early thirties.
That already should tell us something about the quality of these temperature graphs in use. From the fifties to the late seventies temperature is fairly even although some people see a slight cooling and worry about a coming ice age. But suddenly in the late seventies all three official temperature curves turn up and keep on going up. That has been called the late twentieth century warming. It is also Hansen’s warming because in 1988 Hansen stood up in front of the Senate and testified that global warming had started and that we were responsible because we were putting carbon dioxide in the air. Both of these claims were false but global warming movement rests on this foundation.
Fortunately, satellites had started to measure global temperature in late 1978 and this is why we know that the warming he claimed did not exist in 1988. What satellites see in the eighties and nineties is a temperature oscillation, up and down by half a degree, but no warming until 1998 which is ten years after he spoke. And that warming was started by a super El Nino and had nothing to do with carbon dioxide. In four years it raised global temperature by a third of a degree and then stopped. Nothing anthropogenic about it. A third of a degree is half of what has been allotted to the entire twentieth century and this explains the unusual warmth of the first decade of this century.
As to why the temperature curves from NASA, NOAA and the Met Office show warming in the eighties and nineties is simple: they are all cooked. As in falsified. In my book (What Warming?) I show how it is done: they raise the low temperatures between high El Nino peaks which gives the curve an upward slope and call that a warming.
Coordinated action was needed to start it at the same time and an investigation of how this was accomplished is needed. It’s importance far exceeds that of Climategate which is only the tip of an iceberg compared to this criminal conspiracy. Literally trillions of dollars have been swindled out of governments by insisting on the existence of this imaginary warming.
Smokey writes,
“Note to Gneiss and Fred: Anthony has refuted your complaints.”
No, he hasn’t, although he tried changing the subject to tree rings.
“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.”
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.
Just to let these much-hated scientists speak for themselves, here’s a quote from the Supplemental Information that goes with Mann 2008:
“Potential data quality problems. In addition to checking whether or
not potential problems specific to tree-ring data have any
significant impact on our reconstructions in earlier centuries (see
Fig. S7), we also examined whether or not potential problems
noted for several records (see Dataset S1 for details) might
compromise the reconstructions. These records include the four
Tijander et al. (12) series used (see Fig. S9) for which the original
authors note that human effects over the past few centuries
unrelated to climate might impact records (the original paper
states ‘‘Natural variability in the sediment record was disrupted
by increased human impact in the catchment area at A.D. 1720.’’
and later, ‘‘In the case of Lake Korttajarvi it is a demanding task
to calibrate the physical varve data we have collected against
meteorological data, because human impacts have distorted the
natural signal to varying extents’’). These issues are particularly
significant because there are few proxy records, particularly in
the temperature-screened dataset (see Fig. S9), available back
through the 9th century. The Tijander et al. series constitute 4
of the 15 available Northern Hemisphere records before that
point.
In addition there are three other records in our database with
potential data quality problems, as noted in the database notes:
Benson et al. (13) (Mono Lake): ‘‘Data after 1940 no good—
water exported to CA;’’ Isdale (14) (fluorescence): ‘‘anthropogenic
influence after 1870;’’ and McCulloch (15) (Ba/Ca):
‘‘anthropogenic influence after 1870’’.
We therefore performed additional analyses as in Fig. S7, but
instead compaired the reconstructions both with and without the
above”
I see any possible opportunity to destroy this study has been used. I wish you folks that wish to say the earth is now warmer than it has ever been before would take the time to be consistent. Also, take the time to criticize things that apply in the real world. There is a level of mindlessness in not only your criticisms but also in your defenses of the criticisms.
bubbagyro says:
January 29, 2011 at 10:59 am
You are right—Gneiss, Fred and Sir Paul Squarepants, or whoever,
What is telling about them that though their ilk insists the science is settled they still spend a Saturday morning trying to defend what they tell us is already settled. Aren’t there better ways for them to spend a Saturday morning? One would think they’d rest in their settled science and take a vacation. But, as it is, the more there are signs the earth is cooling the more they are working on web sites like WUWT to tell everyone global warming is happening. I came across one of them yesterday who is trying to say we can expect an increase in glaciation as the earth warms more.
So we see science, data, and common sense, none of these things are germane in their movement. To them man is causing the earth to warm, they believe it, and that settles it.
This is an interesting study, but it is one of many.
A look at 6 previously published studies of Alaska, which cover the last 2000 years, indicates that Alaska is much warmer now than it was in the MWP.
http://www.pages-igbp.org/products/newsletters/2009-1/special%20section/science%20highlights/Kaufman_2009-1%2810-11%29.pdf
It would be interesting to see the midge studies and the others analysed with a consistent methodology to compare them and determine an overall trend including uncertainty.
Given that many studies, such as this one, have contradicting results when compared to other studies, what value is gained from stating that ANY study is ‘peer reviewed’?
Roger Knights says:
January 29, 2011 at 11:37 am
Jim says:
January 29, 2011 at 10:58 am
Using biological anything seems risky. I guess if you had a lot of different biological proxies, then you could be more certain. But can’t a virus or bacterium come along and wipe out 1/3 or some number of the midges, like the black plague did humans? Other species have diseases too.
“They aren’t measuring the number of midges, but the ratio of cold-adapted midges to warm-adapted midges.”
Thank you Roger Knights as, though you were answering a different Jim, you answered my questions as well. Like I said in my post, I don’t know much about bugs.
Amino writes,
“What is telling about them that though their ilk insists the science is settled they still spend a Saturday morning trying to defend what they tell us is already settled. Aren’t there better ways for them to spend a Saturday morning?”
My ilk likes multitasking. Me, I’ve been doing a whole bunch of other things while just occasionally dropping by to post a reality-check note at WUWT.
KD says:
January 29, 2011 at 10:59 am
Perhaps this is stating the obvious, but this paper, like the others before it, and the discussion they generate to me lead directly to one very clear conclusion:
There is not enough data to conclude that the climate we are experiencing today is or is not influenced by CO2.
A quick look at Jones CRU 99 dataset for Sitka, Alaska shows that the period from 1869 to 1940 was warmer than from 1950 to present:
http://www.robertb.darkhorizons.org/TempGr/Sitka.GIF
Merovign writes,
“There is, sadly, no argument. Paul, Fred, and Gneiss arrived at this study with conclusion in hand,”
Hah, Fred and I are the only ones here who actually looked at this study to find out what it said. You’ve got reality backwards.
Looks like a fine study to me. Have you read it?
Richard Telford says:
January 29, 2011 at 8:52 am
And thank you for answering my question as well. I now know more about bugs and bat droppings than I ever thought I would want to know. But I guess I still feel there are too many potentail exogenous variables to say too much about the relationship between midge colonies and temperature over thousands of years.
Seems pretty cut and dried to me that the entire AGW theory is as crazy as a rat in a corn crib.
Paul H says:
January 29, 2011 at 10:04 am
“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.”
———–
Indeed. The flood of new research and information that has been unleashed by the partial lifting of the muzzle by Climategate proves one thing – that this debate cannot be over because there is so much still unknown, and so much we are still learning.
This simple reality confirms that anyone screaming that the debate is/was over was being anti-scientific and ideological. The shrill certainty of the AGW gang looks exactly like the rants of religious fundamentalists to me. So do their fear-mongering warnings of floods, droughts and plagues of ‘Biblical proportions,’ not to mention their analogy of hell to come from the planetary fever, IF we do not do what they say.
Gneiss says:
January 29, 2011 at 1:26 pm
“My ilk likes multitasking. Me, I’ve been doing a whole bunch of other things while just occasionally dropping by to post a reality-check note at WUWT.”
Jack of all trades, master of none.
Rock off Gnasty!
I’ve been reading a couple of archeology subscriptions for 35+ years. This study is in line with decades of similar findings. tonyb‘s links are perfect examples.
Gneiss says:
“”Me, I’ve been doing a whole bunch of other things while just occasionally dropping by to post a reality-check note at WUWT.””
Wow. Could this guy be any more condescending?
Gneiss is avoiding the fact that guys like Trenberth, Mann, Hansen, and the rest of the climate alarmist tax eaters refuse to have any kind of a public conversation with skeptics. That means they don’t have confidence in their claims, which are constantly shown to be based on faulty computer models and an adjusted temperature record.
The final straw for me was Trenberth’s plan to replace the null hypothesis with his own. But trenberth doesn’t own the climate null hypothesis, it’s been used by climatologists and meteorologists for longer than Trenberth has been around. Whenever someone says “It’s the warmest it’s been since 1880” (or whatever year) they are making use of the null hypothesis. It shows that the temperature was higher in the past.
Really, there’s nothing to show that the climate now is any different at all than it’s been in the past. How about that, Gneiss?
KD, the fact is that newer methods are more accurate than midges, and a reason for leaving them off a graph of historical temperature is often just to hide the incline, which I mentioned earlier is quite substantial in Alaska and is relevant to this discussion thread, even if not the original paper.
re post: bubbagyro says: January 29, 2011 at 10:14 am
Bubbagyro, meta-analysis, done properly, can be powerful as you note. The devil is in the details however, and meta-analysis are generally far less reliable than individual well done studies. With meta-analysis, it is far too easy for inappropriate selection or groupings of studies to occur, or for researcher bias to be introduced, cherry-picking of which studies to include or exclude, etc. Every possible error for an individual’s work can be introduced into a meta-analysis, plus errors associated with the selection and groupings. As a result, it behooves one to always look at meta-analysis with a very very skeptical eye. It used to be that meta-analysis results and studies were automatically somewhat looked down on because it is far easier to research and massage other researcher’s data and work than it is to actually get into the field or the lab and do one’s own original work – even when perhaps that work is validating another researcher’s work.
Then you throw on top of all these problems that exist even with relatively simple meta-analyses looking at the identical type of research at least, with all the problems associated with trying to do something of this nature using research of different types of proxies, from different regions of the world, which may have had climate changes at slightly different time periods, along with the issues of possible timing lags or errors associated with each type of proxy, etc., etc.
It’s entirely possible that even a reasonably well done meta-analysis of this sort would wind up giving utterly incorrect results.
To all of Gneiss’s comments:
Gneiss, saying that something is so doesn’t make it so. Readers of this website, and of Climate Audit, know all the tricks and denials that Michael Mann and company have used to try to keep their sinking ship afloat all these years. I don’t know if you have followed what Steve McIntyre has found over the last 6 years or so of pursuing the data Mann would not share, and of analyzing it when he found it.
If you really believe that Mann and the Hockey Team’s efforts have:
* used appropriate statistical tests, and have passed them; and
* that there was nothing wrong with their using the upside down Tiljander series to show warming when they had been warned that (1) they was using it upside down, and (2) the series was contaminated by 20th C activities, but they used it anyway;
* that the use of a very small subset of the sample of trees from Yamal was appropriate when the use of the entire series would have shown opposite results contra to the hockey stick;
* that it was appropriate for members of the “team” to try to keep McIntyre’s accurate reviews out of print even if they had to “change the meaning of peer review” (a quote from Phil Jones in the Climategate emails);
* that it is OK to use hockey sticks so non-robust that they depend on just two of many tens of tree ring series (western US bristlecones and a select series from Yamal) are acceptable temperature records when exclusion of these two series makes the hockey stick disappear;
* that it is OK to truncate the tree ring record when it shows declines in temperatures after 1960 and to then “hide the decline”, but it is then also OK to use tree ring records after 1960 when they show an increase (the Yamal trees, but only the small part of the series that does show an increase, when the larger series does not)….
If you believe these things, then you need to go to Climate Audit and do some searches and understand these issues better than it seems you do.
But you may be doing something different here. You may just be trying to blow smoke. Politicians have a phrase that describes some of what they do: “Perception is reality.” Keep repeating something, and eventually it becomes perceived truth. That is what the global warming machine had been doing, successfully, before Climategate. It is a little harder now, but I sense that the climate change perdition community is still trying to create a perception that everything is going to hell in a handbasket unless we do what the IPCC says we should do.
I’m wondering which of these you are — someone who hasn’t actually explored all the work that McIntyre and company have done to show how bogus the hockey stick record is? In other words, a victim of not reading both sides? Or someone who is just being political, not scientific, and is blowing smoke at us?
Ummm……
As Anthony appears to be too humble to mention it, he has added an addendum (very well written) to his original post.
Well worth the read.
John writes,
“But you may be doing something different here.”
You give me too much credit, I’m not nefarious or tricky. I was trying to get Anthony and others to actually read, and honestly describe, the article that his post was about . Initially he had not done so, but I see that he subsequently rewrote his original post. So in that sense my work here was successful.
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.
This is a good article.
I am glad we are getting past the “proxies are evil” idea.
@ Gneiss
Talks about the signature run-up of modern global warming. Hug? What has he been smoking? That implies there’s something unique here and there clearly isn’t.
@Kirly
I also eyeball a trend over the last 4000 years or so that warm intervals are geting shorter and cold intervals longer.
@ R. Gates
You say, “Indeed, since the bulk of the 20th century warming occurred after that date…” (late 60’s). Are you daft, or deliberately disingenuous? Actually, only the bulk of the second half of the 20th century’s warming occurred after that date. You completely ignore the warming that occurred in the first half of the 20th century, of nearly equal magnitude, followed by cooling.
Note the similarities of this graph to that constructed almost a century ago by Elsworth Huntington from red wood tree rings and the levels of Owen Lake:
http://enthusiasmscepticismscience.wordpress.com/global-temperature-graphs/1924_huntington_civilizationandclimate_p321/
MWP and Roman peaking are vaguely aligned, as are the dark ages troughs. At that time global climatology was mostly looking to measure warm-dry to cool-wet variations and it saw rainfall as the key factor. In his work in the 1960s & 70s Hubert Lamb developed on earlier research (including by Huntington) concerning marked variations in the 14th and 15th centuries (Black death and early Renaissance). Most notable was that there seem to be some very wet (& cool??) periods that impacted negatively on civilisation in northern climes. While Huntington, Lamb and Clegg all note wide variation in this pre-LIA period, Huntington’s climatic optimum/min graph here runs in reverse of what Lamb and Clegg find for temp variation in Central Eng and Alaska respectively. Generally, I have found data on this period most varied and contradictory.
I like tree-rings, bugs bite.
Rob Wilson et al 2006: Cycles and shifts: 1,300 years of multi-decadal temperature variability in the Gulf of Alaska. PDF
Lot of trolls stopping by.
The hoped for purge, by the new congress, of the thousands of scientists wasting taxpayer dollars studying settled science can’t already be filling the troll rolls, can it?
Gneiss
Go out in the streets of New York or Dublin and tell people global warming is happening. You’ll find a reality check.
Mike’s Nature trick—something this study didn’t use. 🙂
Gneiss says:
“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.”
The “regulars” here come in all sizes. There is no censorship of views here, as there most certainly is at realclimate, climate progress, etc. I have yet to get a single comment past moderation at those blogs.
And FYI, neither I nor most here have ever taken the position that AGW is non-existent. The problem is that alarmists want to make AGW significant, when there is zero evidence that CO2 has ever caused any global harm. Evidence shows that the AGW effect is too minor to bother with.
I will stand corrected if you can produce testable, empirical evidence showing that CO2 — specifically — has caused global damage. Having asked this question of alarmists numerous times, they have come up with exactly *zero* evidence that CO2 causes global harm.
Conclusion: More CO2 is harmless, and it is beneficial to the biosphere. The sooner you understand that, the sooner the scales will fall from your eyes. CO2 is life – and the biosphere is starved of it. More is better; there is no downside.
Speaking of the poor science found in Mann’s Hockey Stick:
Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium”….
National Academy of Science report on the Mann Hockey Stick, page 4
http://www.nap.edu/openbook.php?record_id=11676&page=4
“There is no censorship of views here”
Of course there is, Smokey, do you honestly not know that?
Anthony Watts says:
REPLY: No you aren’t confused. Neither am I. Dr. Mann et al is a different matter altogether. I’m glad you have come to the conclusion that Mann’s work suffers from the same sort of uncertainty problems. There may be hope for you yet.
As the authors point out, more lake studies are needed to confirm, and as more studies are done, the confidence may increase, or the study may be disproven. It would behoove Mann et al to take the same path, rejecting those 12 trees in Yamal as an insufficient and perhaps cherry picked sample (YAD061) and run the full Schweingruber set and see what they get. – Anthony
More lake studies have already been done, and analysis of 6 of them shows a different relationship between modern temperatures and the MWP in the Arctic, including some lakes in Alaska. This doesn’t agree with the conclusions from the above study involving midges.
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
Gneiss says:
January 29, 2011 at 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.”
=======
Persuasion and beliefs, have no place in science.
A proof of your term “real”, is requested.
Otherwise, I usually enjoy reading your comments.
Amino, let’s add back in some of the rest of that quote.
Why did the National Academy of Sciences have low confidence in Mann’s 1999 conclusion that the 1990s were the warmest decade, and 1998 the warmest year, in a millennium?
because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales.
So, other scientists thought Mann overconfident about that decade and year. But what did they think regarding longer timescales?
The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on icecaps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward.
Gneiss says:
January 29, 2011 at 1:37 pm
“Hah, Fred and I are the only ones here who actually looked at this study to find out what it said. You’ve got reality backwards. Looks like a fine study to me. Have you read it?”
Son, this forum is for discussion of issues. If you have an argument to make, make it. State it in your own words. If you do not state it in your own words, I conclude that you do not have the ability to do so. I stop reading you.
If you need to send us to an article, you are presuming to assign homework. In that case, I conclude that you are a third-grade school teacher whose disguise is not yet perfected.
Gneiss,
Whose views are censored here? Name names.
And the NAS statement has been debunked here so many times I’ve lost count. Prof Richard Lindzen lays out chapter and verse about how these organizations have been co-opted by radical CAGW advocates. And he, I think, knows more about it than you do.
Anyone who buys into the ridiculous Mann Hokey Stick’s flat handle [no MWP or LIA] has drunk the True Believer Kool Aid. In addition to ice core proxies — accepted as being the best proxies for the geological record, there are numerous proxies all over the world that verify the MWP.
The fact of the MWP sticks in your craw, doesn’t it? Because with a warmer MWP, current temperatures are nothing unusual, and your cAGW fantasy goes down in flames.
“The fact of the MWP sticks in your craw, doesn’t it? ”
Not at all, Smokey, you’re imagining that. The MWP appears prominently in some data that I work with, and some articles I have written.
[ why not share one of your articles with us then? ~mod]
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.
@-Smokey says:
“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. ”
A ‘corrupted proxy’ sounds particluarly evil…. reminds one of a naive young girl in the clutches of Casanova, or what happens to politicians when they gain power…
Corruption is usually a term applied to the ethical actions of people. When applied to inanimate objects or data it is metaphorical and should not carry the implication of moral decay.
But then the data can be more precisely described as an inaccurate proxy for temperature. The data is not corrupt, it is what it is. It just may not be a particularly good proxy for temperature. I am sure that in characterizing the data as (metaphorically) corrupt you did not intend to imply that Mann was ethically corrupt….
Izen,
You may be right. Ms Tiljander unwittingly used a bad proxy, it was not deliberate.
But in the case of Michael Mann, using Tiljander’s proxy after he had been informed that it was no good was deliberate, devious, corrupt, unethical scientific misconduct.
He only issued his correction after he had been caught. But he knew all along that his paper was fraudulent.
@- Smokey
I have no wish to get embroiled in the shallow controversy about the moral probity of personalities in the Mann/Tiljander issue. But the way in which data is used when it is sparse and uncertain is a problem in science – and not just in climate research.
Medical research is notorious for its use of highly uncertain data with small sample sizes and multiple confounding factors pressed into service when the available data is sparse. It increases the uncertainty of the end result, but often it is done just to see if (despite all the problems with the data) it refutes the hypothesis that the papers is advancing.
The paper on past climate derived from the midge deposits in the Moose lake sediments is an interesting paralel to the Tiljander data. Like those data there is significant uncertainty that they can be accurately correlated with the instrumental temperature record. As the authors note there are human impacts on the lake ecology that may reduce or remove the link between temperature and midge numbers that the authors hypothesize was operating before that human influence. At present the lake goes eutrophic in the summer with strong algal blooms.
It is clear from what the authors write in the paper that they have some confidence that the data they have collected indicate the direction and rough magnitude of temperature variation over past millenia at the lake. It is also clear that they have less confidence that the absolute value at any time in that past record can be directly correlated with present temperatures.
So the data may give a robust picture of past anomalies, but cannot be matched to the instrumental temperature to give a comparison between present and past absolute temperature values. The illustration of this is that the authors have to use instrumental data from Gulkana airport Alaska to overlap with the sediment data from Moose lake Alberta despite the fact it is ~200 miles further North, and a thousand miles West in a different ecology and climate area.
In this it shares the problem with the Tiljander data, its information of the pattern of past changes may be good, but it cannot be directly linked to current conditions.
So if any future paper uses this midge data to reconstruct past climate should that paper be rejected because the data cannot be effectively correlated with the instrumental record?
Or would it be sufficient to discuss the problems with ‘joining’ this data set to the instrumental record and show that if it is omitted from the reconstruction it makes no difference to the result?
Izen says:
“I have no wish to get embroiled in the shallow controversy about the moral probity of personalities in the Mann/Tiljander issue.”
It is not a “shallow controversy,” or even a controversy at all. And probity seems to be entirely missing. Mann’s shenanigans go straight to the heart of the corruption endemic to mainstream climate science. See this short article to understand what is happening.
And the Tiljander proxy is not comparable to the midge proxy, because Tiljander was falsified well before Mann’s paper was published.
Other than those two issues, I don’t see anything in your comments that I disageree with.
Regardless of the details of midge taxonomy, I have a question for the AGW faithful: How did polar bears make it through the Minoan Warming?
@ – Smokey
Yes, I remember most ofthis malarkey from the reports and articles at the time.
First I would say that I regard the most accurate, and useful, aspect of the original MBH98 paper and the ‘iconic’ graph are the error bars. They make any other claims from the paper moot.
The Tiljander issue is just a replay…
At the risk of exacerbating any strong disagreement rather than reducing it, here’s my take on all this paleoclimate spin.
First, whatever Nature did with the climate in the past is only partially discoverable from the historical record. Strong claims from such evidence is subject to high uncertainty. Its prior distribution should be considered very wide in (rather rough!) Bayesian terms. What various scientists/polemicist THINK it did has absolutely no influence on the reality.
Second , There are two possibilities.-
1) The present warming is unprecedented in human evolutionary history (exclude the PETM and major meteorite impacts) and that exceptionality indicates its anthropogenic origin.
2) The present warming is comparable with past ‘natural’ variation and therefore the rate and magnitude of the warming cannot be used as evidence for its specific anthropogenic cause.
At present the knowledge of the paleoclimate is insufficient to distinguish between these two options unambiguously.
Third…. It doesn’t matter.
The claim that past natural variation is comparable to the present does not refute the hypothesis that the present warming is anthropogenic. It fails to support it, but there are much stronger reasons to attribute the warming to human changes to CO2 than an assumption the warming is exceptional compared to the paleoclimate.
If the present change in climate is similar in past changes then it provides no evidence that the present change is also natural, just that the climate is is capable of variations of that magnitude. Which begs the question – HOW.
And implies a greater degree of sensitivity to small changes, enhanced positive feedbacks, when natural processes do affect the flow of energy through the climate system.
I know it may seem this gives the AGW ‘side’ a win-win scenario on paleoclimate, but I can see no logical alternative given the two options.
If the present warming is exceptional it supports the existing case for its anthropogenic cause.
If the ‘natural’ climate variations can duplicate present observed changes then that has little impact on the other evidence for it present attribution to the CO2 rise, but it does imply a greater sensitivity of the climate system to small changes in the energy balance.
If the MWP really was globally synchronous and comparable with the present temperature then energy was required. Some physical process must have reduced the amount of energy lost from the tropopause to less than that received from the sun. No other mechanism is capable of raising global temperature while the solar output is within the known constraints imposed by Be10 and C14 production (among other evidence).
That requires a climate system that is NOT strongly homeostatic, that small variations within the decadal-century climate processes are amplified to make global temperature changes that have had significant impacts on previous human civilizations.
While many European societies seemed to flourish during the MWP, or Medieval Climate Anomaly as it is more cautiously described, the hotter drier climate on the American continent resulted in the fall of most of the city-state agrarian cultures that had arisen there.
But this strays away from the science of what NATURE is going to do, and into how robust our global society may be in the face of change, natural or anthropogenic.
And that is a whole ‘nother can of worms…..
Izen says:
“There are two possibilities.-
1) The present warming is unprecedented in human evolutionary history…”
Let’s take that one first. The present warming is well within the parameters of the climate during the Holocene. And if we look further back, the parameters are much wider. As you can see, declining temperatures are the real threat.
And as you can see in this chart, based on Phil Jones data, nothing is happening now that hasn’t happened before. In fact, the current *mild* warming cycle of 0.7°C over the past century is much less than many previous warming cycles. That’s why Trenberth is so anxious to get rid of the null hypothesis: it shows that the current cycle is indistinguishable from climate cycles prior to the industrial revolution.
Occam’s Razor says that extraneous variables should be avoided, and that the simplest explanation is generally the best. CO2 is an extraneous variable. Although there is probably some minor warming due to the rise in CO2, it is too insignificant to be measured.
And if the climate had a large sensitivity to that minor trace gas [such as the preposterous 3° – 6° or more opined by the IPCC and others], then temperatures would closely track the CO2 rise. They don’t.
Which brings us to your next point:
“2) The present warming is comparable with past ‘natural’ variation and therefore the rate and magnitude of the warming cannot be used as evidence for its specific anthropogenic cause.”
That is the null hypothesis: the statistical hypothesis that states that there are no differences between observed and expected data.
The null hypothesis has never been falsified. As Dr Roy Spencer puts it: “No one has falsified the hypothesis that the observed temperature changes are a consequence of natural variability.”
The null hypothesis is the hypothesis against which any alternative hypothesis must be tested. If there is no measurable difference, then the alternative hypothesis is falsified.
Next, you ask:
“If the present change in climate is similar in past changes then it provides no evidence that the present change is also natural, just that the climate is is capable of variations of that magnitude. Which begs the question – HOW.”
The ‘magnitude’ is actually quite small. A change of 0.7°C is routine. As Prof Richard Lindzen explains it:
Finally, the MWP has an enormous amount of research supporting its existence. Mann tried to claim that neither the MWP nor the LIA existed, by making the handle of his hockey stick straight. But after the debunking of MBH98/99 by McIntyre, McKittrick and Wegman et al, the IPCC was forced to stop using it in their publications.
But for the sake of argument, and supposing that there was no MWP, there were other warming cycles that exceeded it in magnitude. Which shows that the current climate parameters are nothing new. In fact, right now we are in a “Goldilocks” climate: not too warm, not too cold, but ju-u-u-u-st right.
Try to accept the fact that at current and projected levels, CO2 is a harmless and beneficial trace gas; no global harm due to the rise in CO2 is evident, and increased agricultural production due to the rise in CO2 levels has been repeatedly demonstrated. It’s all good.
OK, but it was fun….
Smokey says:
“The present warming is well within the parameters of the climate during the Holocene.”
Depends on how you define those parameters and how much confidence you have in the paleoclimate reconstructions.
The certainty with which you make that statement indicates you grant more reliability to paleocliamte research than I would. But then I see a lot of comfirmation bias in this area – from both sides.
“Occam’s Razor says that extraneous variables should be avoided, and that the simplest explanation is generally the best. CO2 is an extraneous variable.”
Actually the raised CO2 is the simplest explanation for the observed climate change. Anything else needs additional (undetected) extraneous variables in the ‘natural’ factors that would explain the warming.
I would question the other assertions you make about the supposed insignificance of the warming in terms of energy change and the beneficial effects of raised CO2, but that can wait for threads where such subjects are pertinant.
The fact we live in a ‘Goldilocks’ climate is because we have adapted, and designed our societies and agricultural practises to this climate. How easily we will adapt when ocean acidification or enhanced growth of C3 type ‘weeds’ affecting our food production and the climate changes is uncertain….
Izen,
Fortunately, scientific skeptics are mostly immune from the cognitive dissonance that afflicts true believers in CAGW, because a skeptic’s job is simply to debunk that alarmist conjecture. Skeptics don’t invent fantasies like CO2=CAGW. Skeptics merely ask questions and point out inconvenient facts.
You look at the charts I provided, and immediately go into Orwellian doublethink: black is white, down is up, evil is good, and the climate is controlled by a minor trace gas. Ri-i-i-i-ght.
You have everything wrong, and you can’t see it. The parameters of the Holocene are provided in the very first chart above, which shows that we are currently pretty close to the average temperature for the past ten thousand years; a Goldilocks climate. Yet you inconguously presume that the current benign climate is due to our “societies” and “agricultural practises (sic)”. Pray tell why during the past ten millennia, before the industrial revolution and modern farming methods, the planet’s temperature looks just the same as today? Natural climate variability fully explains that verifiable fact.
I gave you Prof Lindzen’s explanation for the natural warming/cooling cycles… and you let it fly right over your head. You are determined to blame a harmless, beneficial trace gas for your alarmism, and contradictory facts from an internationally esteemed expert don’t matter.
That is not science, that is True Belief; anti-science. Based on his experience and knowledge, Dr Lindzen has probably forgotten more than you will ever learn about atmospheric physics. [Unless, of course, you want to show us what passes for your CV, which I assume consists of reading realclimate a couple of hours a day.]
You wisely avoided the comparison of the repeatedly falsified CO2=CAGW conjecture when compared with the never falsified null hypothesis [unless you claim to know more than another esteemed climatologist, Dr Roy Spencer]. Note that CO2 rises follow temperature rises – not vice-versa. But for those afflicted with doublethink, that contradictory fact doesn’t carry any weight at all.
Nothing is different in today’s climate compared with Holocene averages or parameters. There may be a slight amount of warming from the rise in CO2, but I’ve shown that it is entirely beneficial. Warmth is good. Cold kills. And cognitive dissonance closes your mind to reality: CAGW is an entirely trumped-up scare. Demonizing “carbon” is pablum for the scientifically illiterate.
You say there is confirmation bias on both sides. Not on mine, there isn’t. I’m not frightened by the “carbon” scare, which is based on grant money, university status and international politics. Nothing out of the ordinary is happening, despite decades of failed predictions of doom. Astonishingly, after being proved wrong every step of the way, the alarmist crowd is still convinced that climate catastrophe is right around the corner. Cognitive dissonance.
You’ve drunk the alarmist Kool Aid for too long. Now you’re so hooked on it that perfectly natural cycles take on a sinister meaning. You see what you want to see because so much of your life is invested in the CAGW canard.
As each putative CAGW effect is debunked in turn, your belief system only gets stronger, like the followers of Mrs Keech’s flying saucer cult. The flying saucer didn’t arrive on schedule, so that could only mean it was delayed. It couldn’t possibly mean there aren’t any flying saucers. Being proved wrong only strengthens the belief in those afflicted with cognitive dissonance.
Sea level rise accelerating? Debunked. Global ice cover disappearing? Debunked. Coral bleaching? Debunked. They’ve all been debunked. Yet you continue to believe what Al Gore instructs you to believe. Very sad.
eadler says: January 29, 2011 at 7:56 pm
You are incorrect, science should not be done by subjectively assuming that the discrepancies with your work and others is automatically due to faults in your own work. An objective analysis would simply present the results without interpretation in relation to other work. I have no access to the peer-review process of this paper and thus hold nothing but skepticism based on previous examples involving paleo-climate reconstructions and the fact that this papers cites Mann whose work has nothing to do with midge analysis of lake sediments. Caution can be mentioned in an objective way but that was not done in this paper.
I would like to contribute some brief comments to this thread:
(1) With respect to the value of the Moose Lake record for assessing global warming:
As the name implies, global warming refers to an increase in the heat budget of the entire planet; the global heat budget is affected primarily by radiative controls, including (but not limited to) solar activity and orbital variations that alter how much energy Earth receives, and albedo and greenhouse gas concentration changes that alter rates of energy loss to space. Changes to the global heat budget can only be assessed by hemispheric or ideally global composites of temperature time series. The Mann et al. publication was a pioneering example of this; additional global composite records have since become available.
Local atmospheric conditions are by far the most important controls on temperature trends at an individual site. Recent mean annual temperature rises in Alaska for instance have been attributed to changes in an atmospheric mode known as the North Pacific Index (NPI), for example. Better-known examples on other regions of the globe are the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). However, changes to the globe’s heat budget can significantly alter the frequency or amplitude of these atmospheric circulation patterns.
Recent warming in Alaska, while occurring throughout all months, is dominated by warming in the winter months. Winter is also the season with the strongest atmospheric patterns in each hemisphere due to the intense heat gradient between the tropics and the polar winter. Summer temperatures in Alaska are predominantly governed by cloud radiative forcing today. Comparing modern warming estimates of mean annual temperature with the midge data which only capture mid-summer conditions is a bit like comparing apples and oranges.
The fact that warming predominately occurs in winter is not trivial at these high latitudes, as winter conditions play a large role in influencing permafrost temperatures in summer, and hence can play a role in the development of a thermokarst landscape with potential positive greenhouse gas feedbacks.
(2) A comment on paleotemperature inferences:
Measuring prehistoric temperatures is crucial to gain a context for recent changes, and also to identify natural variations and perhaps even drivers of natural climate variations that play a role on longer timescales. However, it is a bit like measuring with a noisy thermometer. In this case, midge species differ in their temperature preferences, and multivariate analyses show that summer water temperature is one of the dominant factors that explains the geographic distribution of different species of midge larvae. These relationships can be used to get an estimate of the average summer temperature at the time a sediment interval was deposited by identifying its larval midge remains. As might be expected, the precision of that estimate is far lower than reading a temperature value from a thermometer. Additionally, midges are biological organisms that respond to other environmental controls. Water depth, pH, cation concentrations, and nutrient status of lakes are a few examples. A good comparison with instrumental data is an encouraging sign that midges at a particular site are reliable indicators of temperature; other multivariate techniques can also be used to try to identify periods during which the midge assemblages may have been affected by environmental factors other that summer temperature. However, it is important to keep this caveat in mind – it is one of the principle reasons why replication of such studies is crucial. The second paragraph of the paper’s section 4.4 deals with such a possible caveat. The shift to on average higher temperatures between 4000 and 5000 years ago could have been influenced by low lake levels that were indicated by other lines of evidence. Other factors may have contributed during other periods but left no sign in the sediment. The more records that become available in the same region that point to shared temporal trends, the higher the confidence that the patterns represent regional controls (e.g. including temperature), rather more lake or watershed-limited controls, such as changes to the pH or cation composition of the lake’s water.