Over at Climate Audit, Steve McIntyre has found yet another unexplainable inclusion of a hockey stick shaped proxy in the PAGES2K paper. What is most interesting about it is that when you look at the proxy plot panel, it reminds you of the panel that Steve plotted for Yamal, where just one proxy sample went off the rails as an apparent outlier and seems to dominate the set. Since even a grade school student could pick this proxy out in one of those “which one of these is not like the others?” type test questions, one wonders if this particular proxy was preselected by Kaufman specifically for its shape, or if they just bungled the most basic of quality control inspections. Of course, when Steve asked those questions, Nick Stokes showed up to defend the indefensible, and hilarity ensued.
Steve McIntyre writes:
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Kaufman and paleo peer reviewers ought to be aware that the recent portion of varve data can be contaminated by modern agriculture, as this was a contentious issue in relation to Mann et al 2008 (Upside Down Mann) and Kaufman et al 2009. Nonetheless, Kaufman et al 2013 (PAGES), despite dozens of coauthors and peer review at the two most prominent science journals, committed precisely the same mistake as his earlier article, though the location of the contaminated data is different.
The contaminated series is readily identified as an outlier through a simple inspection of the data. The evidence of contamination by recent agriculture in the specialist articles is completely unequivocal. This sort of mistake shouldn’t be that hard to spot even for real climate scientists.
Here is a plot of the last nine (of 22) Arctic sediment series. One of these series (top left – Igaliku) has the classic shape of the contaminated Finnish sediment series (often described as upside down Tiljander). Any proper data analyst plots data and inspects outliers, especially ones that overly contribute to the expected answer. The Igaliku series demands further inspection under routine data analysis.
Figure 1. Plot of last nine (of 22) Kaufman et al Arctic sediment series. The Igaliku proxy is total pollen accumulation.
The Igaliku series is plotted separately below. It is also available at a NOAA archive here , which actually contains one additional recent value plotted in red. The NOAA archive contains many other measurements: it is unclear why Kaufman selected pollen accumulation rate out of all the available measurements.
The resolution of the data set is only 56 years (coarser than the stated minimum of 50 years) and only has three values in the 20th century. The value in 1916 was lower than late medieval values, but had dramatically surged in the late part of the 20th century.
Figure 2. PAGES2K Igaliku series.
Igaliku is in Greenland and was the location of the Norse settlement founded by Erik the Red and is of archaeological interest. Sediment series from Lake Igaliku have been described in three specialist publications in 2012:
Massa et al, 2012. Journal of Paleolimnology, A multiproxy evaluation of Holocene environmental change from Lake Igaliku, South Greenland. (Not presently online). (Update: online here h/t Mosher. I’ve added a paragraph from this text referring to pollen accumulation.)
Massa et al 2012. QSR. A 2500 year record of natural and anthropogenic soil erosion in South Greenland. Online here.
Perren et al 2012, 2012. Holocene. A paleoecological perspective on 1450 years of human impacts from a lake in southern Greenland. Online here.
The three articles clearly demonstrate that the sediments are contaminated as climate proxies.
Igaliku has been re-settled in the 20th century and modern agricultural practices have been introduced. The specialist publications make it overwhelmingly clear that modern agriculture has resulted in dramatic changes to the sediments, rendering the recent portion of the Igaliku series unusable as a climate proxy. Here are some quotes from the original article.
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Read Steve’s entire essay here: More Kaufman Contamination
Nick showed up to argue that the Igaliku really isn’t contaminated by agriculture at all, and is currently engaged in an multi-front battle of deny, duck, and cover. The obstinance on display to prevent admitting the obvious is diamond hard. This isn’t unusual, as Nick was associated with CSIRO, where admissions aren’t part of the government funded manual. Gadflies and racehorse comparisons were bandied about and now Steve has taken to calling Nick “racehorse” much in the same vein as Tamino and his self proclaimed “bulldog” status.
To say watching this is entertaining, would be an understatement. Meanwhile there have been many updates and piling on of additional evidence for contamination. Nick is now reduced to rebutting Steve with Bill Clinton style questions (“It depends on what the meaning of the words ‘is’ is.”) such as: “Could you say exactly what you mean by “contaminated core”?”
Here is my contribution that I left as comments:
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Steve writes:
The three articles clearly demonstrate that the sediments are contaminated as climate proxies.
Igaliku has been re-settled in the 20th century and modern agricultural practices have been introduced.
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By way of support for this, photos can tell you a lot.
Google Earth’s aerial view clearly shows the developed agriculture signature:
And from the ground, hay bales in Igaliku from the Wikipedia page on Igaliku:
The slope of the land drains right into the lake, and along the slope is clearly human agricultural development.
O’Rourke and SOlomon 1976 have recently found that total pollen influx was a direct function of sediment influx in varved sediments from seneca Lake, New York.
Given the drainage pattern of the land, it seems like a clear case of sediment contamination to me.
Kaufman has followed his rules, which are to use proxies which:
“(5) exhibit a documented temperature signal, and (6) are
published in peer-reviewed literature as a proxy for temperature”
One wonders though if Igaliku wasn’t preselected due to the shape of the data without any other considerations.
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Note: the Google Earth image is of the town near the fjord, the Wikipedia picture of the lake where sediment was sampled is in the highland just to the NW of the town. You can inspect the map here and see the lake (which is ice-covered in the satellite photo):
http://maps.google.com/maps?q=60.987778,-45.420833&ll=61.009153,-45.439453&spn=0.053414,0.185394&t=h&z=13
Update: here is another view of the lake from the ground, showing agriculture all around the catch basin, thanks to Nick and anonymoose http://www.panoramio.com/photo/12426959
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EdeFPosted Apr 30, 2013 at 12:27 AMIgaliku reminds me of the small farms in the Okanogan River valley of central Washington state. Note that dirt would wash into the lake from the several roads going up to the higher country.
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Anthony WattsPosted Apr 30, 2013 at 12:37 AMExactly, basically what agriculture does is increase the pollen catch-basin area though land use change. Fighting runoff and erosion is always an issue with agriculture.
With a larger area near the lake having undergone land-use change, it will allow more runoff, and therefore more pollen to be funneled into the lake. Kaufman was probably never a farmer and wouldn’t get this, or maybe he simply didn’t want to since that uptick looks so “elegant” when trying to fit the theory to the data.
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Anthony WattsPosted Apr 30, 2013 at 1:14 AM
Figure 2 from PAGES 2K has an interesting pollen bump from about 1150-1400.
I think I’ve found a proxy for that. Modern day Igaliku is on the same site as Garðar, Greenland, which had a period of growth during the MWP.
Garðar was the seat of the bishop in the Norse settlements in Greenland.
Garðar had enough success as a town to warrant the Catholic Church to issue a permanent Bishop for the construction of a cathedral there. The first bishop of Garðar, Arnaldur, was ordained by the Archbishop of Lund in 1124. He arrived in Greenland in 1126. In the same year he started with the construction of the cathedral, devoted to St. Nicholas, patron saint of sailors.
To support something like that, you need a successful agricultural base. People that are starving don’t have time for such luxuries.
Bishop Álfur was ordained in 1368 and served as last bishop of Garðar until 1378. The Greenland diocese disappeared in the 1400s, when the ship departures from Norway stopped.
If you look at this table of Bishops, it seems to correlate with that bump in the pollen data, then dives after 1400.
Bishop Served years
Arnaldur First-Bishop 1124–1126
Bishop Arnaldur 1126–1150
Jón Knútur 1153–1186
Jón Árnason 1189–1209
Þór Helgi 1212–1230
Nikulás 1234–1242
Ólafur 1242–mid-1280
Þór Bokki 1289–1309
Bishop Árni 1315–1347
Álfur Last-Bishop 1368–1378
Source: http://en.wikipedia.org/wiki/Gardar,_Greenland
A timeline is here: http://www.greenland-guide.gl/leif2000/history.htm
Bishops would seem to be a proxy for the success of the town, and the success of the town had to rely on the sea and agriculture. When the climate turned colder, the agriculture failed, as we have heard about other areas of southern Greenland.
Of course the pollen bump due to agriculture would have been smaller then than now, since they had no mechanization to amplify the area they could till and plant.
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Bishop Hill might like the Bishops proxy, but Mosher added the real clincher though:
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“Norse farmers settled southern Greenland *985 AD(Jones1986) including the area around Lake Igaliku,which was used for grazing and hay production.Following the disappearance of the Norse *1450 AD,Igaliku was resettled during the 18th century (Arne-borg2007) and large-scale agriculture, based on sheep farming, was developed in the 1920s (Austrheim et al.2008). Consequently, the response to climate changeover the last millennium was overprinted by land-use effects (Gauthier et al.2010; Massa et al.2012; Perrenet al.2012). However, the consideration of human-induced changes at Lake Igaliku in light of the entire Holocene ecosystem development provides new insights about their magnitude.Relative to the preceding Holocene shifts, the vegetation was slightly impacted by land clearanceand grazing, and exhibits a small decrease in woodytaxa abundance (from 60 to 45 %). Until *1335 AD,the related soil erosion, documented by high TOC/TNand MAR values, clearly compounds the long-termincreasing trend (Fig.6). Contrary to the other studiedvariables, the diatom assemblages indicate that thelake ecology was not significantly impacted, and that the changes are within the range of natural Holocene variability.Both in terms of lake ecology and soil erosion, theperiod since 1988 AD is likewise unprecedented in the context of the Holocene by a magnitude and rate of change greater than the previous 9,500 years. The digging of drainage ditches for hayfields caused adramatic increase in MAR, which reached unprece-dented values. The use of nitrogen fertilizers on thesefields (200–250 kg ha -1 yr -1of N, Miki Egede pers.commun.) have outpaced the natural buffering capac-ity of Lake Igaliku, resulting in a sharp rise in themesotrophic diatom, Fragilaria tene
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Nick, in classic Mannian style, refuses to concede. Go help him out at the Climate Audit thread More Kaufman Contamination which is sure to become a classic.
This Stokes-Kaufman incident seems to be a case of land use effect denial.
When the data produces the ‘right result ‘ its quality or lack-off means nothing .
“You can inspect the map here and see the lake (which is ice-covered in the satellite photo):”
Is it the almost-round lake north of town, with a road crossing its outlet on the east side?
Ah… Here is the location of the lake, according to Nick at CA.
http://www.panoramio.com/photo/12426959
Nick pursues classic Mannian style; that is, if a proxy shows a hockey stick then it is a reliable proxy. All evidence to the contrary must be questioned to the point of filibuster. Some day, scientists will become proxy researchers and they will conduct experiments in an attempt to prove that their proxies are not reliable.
The discovery of more 20th century contamination certainly calls into question the quality of paleo climate and peer review. But in a previous post, Steve did something perhaps more important, by researching what the true experts say about varve interpretation over time. Deeper, older sediments compact. Therefore any reconstruction looking only at thickness understates the past compared to the present.
A hockey stick needs a handle and a blade. We know of several creative ways to make a blade. Graft on temperatures ( without frequency shift or calibration, as in Mike’s Nature trick) redate (as with Marcott), use contaminated samples (as here), practice selection bias (as Gergis)…But for AGW to trump natural variability, it is also necessary to have a smooth handle. That is why the MWP and LIA are so important. And relying on varve thickness without taking compaction into account is a beaut that should get all such reconstructions retracted from the literature. But obviously hasn’t and won’t.
‘Kaufman has followed his rules, which are to use proxies which:
“(5) exhibit a documented temperature signal, and (6) are
published in peer-reviewed literature as a proxy for temperature”’
So, any proxy that has been referenced in peer-reviewed literature is a reliable proxy? That means that any such proxy and the research which produced it are beyond criticism. Can one be more anti-science than that? People who hold such views are not even interested in science.
Stokes is showing his arse again over at CA…..
Slightly off topic, but does anyone know how those farms are doing?
Thank you to Nike Stokes for debating the other side of the argument. His comments have helped me to understand this issue at a deeper level than would have been possible otherwise. Shame on you people for belittleing (sp) him for his views. From Nick I hear no ad hominem attacks. I dont agree with him but admire him for stating his view as unpopular as they are.
“Nick showed up to argue that the Igaliku really isn’t contaminated by agriculture at all,”
That’s not what I said at all. Steve’s argument was that Massa et al, the original authors, had said that nitrogen fertilizer use invalidated modern measures involving diatoms and isotope ratios. I pointed out that this did not apply to pollen, which came from elsewhere, and for which the mud was simply a place where it lodged and could be counted, and that Massa et al had said that the pollen count did in fact document climate change over the last millenia. That data is what Kaufman used.
But my main argument, put several times, is this. Climate Audit stated very firmly, just a few days ago
“Perhaps the greatest single difference between being a “real climate scientist” and policies recommended here is that “real climate scientists” do not hesitate in excluding data ex post because it goes the “wrong” way, a practice that is unequivocally condemned at Climate Audit and other critical blogs which take the position that criteria have to be established ex ante: if you believe that treeline spruce ring widths or Arctic d18O ice core data is a climate proxy, then you can’t exclude (or downweight) data because it goes the “wrong” way.”
The Pages2k was a structured program, and it did lay down such criteria:
“The proxy records selected by the Arctic2k group for the Arctic continental-scale temperature reconstruction (Fig. S7) meet the following criteria:
(1) situated north of 60°N,
(2) extend back in time to at least 1500 CE,
(3) have an average sample resolution of no coarser than 50 years,
(4) include at least one chronological reference point every 500 years,
(5) exhibit a documented temperature signal, and
(6) are published in peer-reviewed literature as a proxy for temperature, although not necessarily calibrated to temperature (i.e., some records provide only a relative measure of temperature with unknown transformations between the proxy measurement and temperature).”
Note (5) and (6). The Igaliku pollen record qualifies, so Kaufman included them. Massa et al documented a temperature signal and published it as a proxy for temperature. That’s what CA demands.
Yet you are demanding that ” Since even a grade school student could pick this proxy out in one of those “which one of these is not like the others?” type test questions”
Excluding data ex post, in CA terms. And presumably, urging Kaufman to overrule the original peer reviewed and published result on the basis of his farming knowledge, or whatever. So your demand is “unequivocally condemned at Climate Audit”.
REPLY: Oh please Nick, this is just spin. Do they teach this sort of misdirection in CSIRO wonk school, or or you simply on somebody’s payroll to be this purposely obtuse? The Igaliku proxy is in fact unlike the others, it is clearly contaminated, and clearly a hockey stick shape which suggests it was selected specifically rather than excluded. McIntyre asked you to show a similar proxy, uncontaminated, that shows a similar hockey stick shape, and so far you have ducked that call for comparison.
Until you can demonstrate that, all your defensive hand waving is moot. – Anthony
I am in full agreement with McIntyre and I like the photographic evidence supplied by Watts.
But, let’s assume for argument that Igaliku is a NON-contaminated record and is a valid proxy of “increased CO2 driven climate change”. Igaliku is a pollen count proxy showing a large increase in pollen in the last century. More pollen comes from more plant fertility which logically comes from greater plant biomass which is causally linked by assumption in argument to be the result of increased CO2 and its assumed associated climate change.
Igaliku is either valid or invalid evidence for climate change.
If invalid, it is contaminated and it should not be used for climate change studies. Full stop.
If it is valid evidence for climate change, then the inescapable conclusion is that the climate change is leading to a spectacular increase in pollenating plant life. Now, if there was a decrease in plant life driven by climate change, I would be alarmed. However, an increase in plant life is a cause for great happiness.
Either way, Igaliku cannot properly be used to support actions to mitigate climate change.
This climate reconstruction of the Aral Sea region does not seem to have been incorporated in any of sytheses: http://www.academia.edu/244158/Advances_in_understanding_the_late_Holocene_history_of_the_Aral_Sea_region
which brings up the question, have any of the several recent central Asian proxies (which usually show a strong, early MWP) been included in recent sytheses?
“In China There Are No Hockey Sticks” –http://wattsupwiththat.com/2011/12/07/in-china-there-are-no-hockey-sticks/
Asia is a big continent to ignore. –AGF
Any bewilderment at the submission and endorsement of elementary “mistakes” assumes too much.
There is a limit to intellectual ineptitude no matter how degraded and invalid the “knowledge” base.
That there will be examples of deliberate fraud perpetrated in this field is beyond doubt. There already have been. To assume this is not one is to be insufficiently objective.
For any one wanting a full detailed analysis of why Igaliku data should not be used because of human contamination, both now and during the MWP then this is the paper for you:
http://www.google.co.uk/url?sa=t&rct=j&q=igaliku%202500%20year%20record%20quaternary&source=web&cd=2&sqi=2&ved=0CDMQFjAB&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F230815399_A_2500_year_record_of_natural_and_anthropogenic_soil_erosion_in_South_Greenland%2Ffile%2F9fcfd504d9005867cc.pdf&ei=BTmBUd3aHvOa1AWCjYGoDA&usg=AFQjCNGmu-Y65ktMK9Ejfp7uNxW2xskpeQ&bvm=bv.45921128,d.d2k&cad=rja
Regarding Nick Stokes as “Racehorse”: Scattered comments at CA over the last few months have suggested the tag is an allusion to Harry “Racehorse” Haynes, a particularly tenacious criminal defense lawyer from Texas. I don’t know if Steve coined the nickname over there, but it’s not wholly pejorative; Haynes earned it as a football player in public school, and was decorated in the war, but has since set himself up as one an aggressive defender of particularly notorious criminals. He’s not indifferent to the incentives for doing this. See:
“T. Cullen Davis: The Best Justice Money Can Buy”
http://www.trutv.com/library/crime/notorious_murders/not_guilty/t_cullen_davis/4.html?sect=14
Nick
It appears that you have been hoisted by tour own petard…
“(3) have an average sample resolution of no coarser than 50 years”
The sample fails this at a resolution of 56 years….
Nick
You said above that “Massa et al had said that the pollen count did in fact document climate change over the last millenia” my bold, That is absolutely not true. This is what they said:
Despite the possible influence of land use, pollen accumulation appears to document climatic changes of the last millennia nonetheless. PAR reached minimum values during the Little Ice Age from 1500 to 1920 AD, consistent with maximum glacial re-advance at Qipisarqo (Kaplan et al. 2002) and elsewhere in south Greenland (Weidick et al. 2004; Larsen et al. 2011). It is also coeval with high rates of isostatically driven transgression, which caused the inundation of a Norse graveyard at Herjolfsnæs (Mikkelsen et al. 2008). The sharp increase of Salix/ Betula pollen accumulation rate after 1920 AD (Fig. 6) suggests a rapid warming, which reversed the Neoglacial cooling trend similar to other locations in the Arctic (Kaufman et al. 2009).
There’s a big difference between “in fact” and “appears to” or “suggests”
Looks like a perfect proxy for tracing historical agricultural development. Sorry what was the question again?
Way to go Nick, just skip one of the criteria, (Cuz its close) and then on top of that, since your criteria does not say: “Don’t use contaminated data that are useless as proxies.” You’re golden!
Since they didn’t say were going to exclude crap we have to accept crap.
Also since they choose to include a proxy that violated their rules for inclusion, then EVERY proxy they considered should be listed to see which of those which were close but didn’t include.
Anthony, you are pointing out the village when you show pictures from overhead, but are showing a picture of the lake and its agricultural surroundings taken from nearby. Those are places that are perhaps a mile apart.
The village isn’t on the lake; it’s on the fjord. Note the many acres of agricultural development alongside the lake. I’m guessing 40 acres or more. It’s here:
60.9985°N, 45.4485°W
Paste that into your Google maps; arrow should be dead center on ag complex. Agricultural development in the village area is, I would think, irrelevant to the Lake Igaliku varvology.
Ok, I should really do a better job of reading all of the updates. My apologies; you had noted the separate position of the ag complex here. Perhaps not at Climate Audit, though.
“Eric says: May 1, 2013 at 8:56 am
“(3) have an average sample resolution of no coarser than 50 years”
The sample fails this at a resolution of 56 years….”
A depressing, but sometimes amusing thing about these arguments is the way people bring in one argument after another. Anything that might stick. We have a whole head post that goes on about pollution, contamination etc, and now this alleged shortfall is plucked out. Where does it come from?
In fact, the resolution is generally higher than 50 years. You’ll note the secondary complaint that it has only 3 values in the 20th century. That’s 33 years. I think this 56 yr number is based on that there are 36 records since 0 AD. There are gaps. But in fact, it is a 10000 year record.
But if you want to base your case on a resolution shortfall, then say so, and do the arithmetic properly.
REPLY: Nick here’s something that will “stick” that you refuse so far to answer – show an uncontaminated proxy with a similar shape, per McIntyre. – Anthony
Here’s Nick “racehorse” Stokes playing team water hockey on lake Igaliku, oblivious to contamination
@Nick Stokes 8:40am:
The Pages2k was a structured program, and it did lay down such criteria:
…(5) exhibit a documented temperature signal, …
Ex Post Exclusion. That criteria is entirely circular in studies on temperature signals and trends.
Besides circularity, Pollen Count proxies are only very weakly linked to temperatures. Pollen Count is also a complex function of aridity, competing flora and fauna, fertilization, and cultivation. Pollen count has very non-linear relationship to temperature, and one that is not monotonic.
In a temperature range -20C to 100C, pollen counts will begin at zero, rising into the temperate range, then decline back to zero as desertification takes hold.
Yeah, maybe Pollen Count is “documented” to exhibit a temperature signal of unspecifice coarsness, pal review and all. That doesn’t mean it really has a sensitivity with temperature that can be relied upon to measure fractions of a degree. I’ll sit still for Pollen Count to be a proxy for floral productivity from a variety of influences. But to take pollen count back to a temperature relationship with sensitivity of a fraction of degree C is an amalgam of blindness, arrogance, and trickery.
they will conduct experiments in an attempt to prove that their proxies are not reliable
Or hopefully “more reliable”