Stephen McIntyre’s tweet thread is a delight for old timers of the Climate Wars and has resurrected the issue, or at least the region, of the Enchanted Larch of Yamal.
For those who wish to catch up or refresh themselves, here is the post that launched a lot of hilarity and unadmitted embarrassment for the Climate Consensus Community.
If you want to see a bevy of posts on this subject use this search string in your favorite search engine.
enchanted larch of yamal site:climateaudit.org
And here is the current Twitter thread.
Originally tweeted by Stephen McIntyre (@ClimateAudit) on August 30, 2022.
last week, a new article https://nature.com/articles/s41467-022-32629-x… on Yamal tree rings, co-authored by Osborn and Melvin of East Anglia, claimed “recent Siberian heating unprecedented in past 7 millennia”. @climateofgavin snickered because results similar to prior UEA.
Schmidt illustrated his snicker with seemingly dramatic hockey stick from Hantemirov (Nature 2022). Neither Schmidt nor Nature showed an even more remarkable figure from Hantemirov thesis showing a remarkable southward movement of Yamal treeline thru Holocene, with tiny recent HS
the dramatic southward movement of Yamal treeline in Holocene (observed by Hantemirov) is consistent with long-term decrease in Greenland d18O values (Vinther 2009).
Nor do Hantermirov (or Schmidt) reconcile the seminal findings of Esper et al (Nature 2012) https://www.blogs.uni-mainz.de/fb09climatology/files/2012/03/Esper_2012_NatureCC6.pdf showing lack of responsiveness of tree ring chronologies to the huge changes in high latitude JJA insolation over Holocene (up to 48 wm-2 vs 1.5 wm-2 CO2 forcing)
despite the statement in Nature on supposed data availability, Hantemirov (2022) did NOT archive the underlying measurement data. About 600 of the ~1600 cores were previously used in Briffa et al (2002,2009, 2013) and grudgingly made available.
there is some new and interesing information in Hantemirov (2022)- long sought data on lat-longs of the samples – see Samples tab on spreadsheet at
https://zenodo.org/record/6477133#.Yw4fOXbMKUk
Hantemirov illustrated the locations of their samples in figure shown below (which shows sites on Tanlova, Khadyta, Yada and Portsa rivers). The color pattern doesn’t show any biasing pattern.
Here’s my plot of same location data, coloring by time period – blue oldest subfossil, red modern (living in 1980-2020). An obvious point: modern samples are to far south of range, oldest samples to the north. Note a very ancient Yuribey River sample to north, not shown in Nature
another representation of same location data, showing latitude vs pith (start) year. The modern treeline is far to the south of Holocene treelines and modern (living) samples taken to south of majority of mid-Holocene samples. Note early report of 70N early Holocene treeline
Schmidt and other publicists show the highly smoothed version of the Yamal data. The unsmoothed version (unsurprisingly) is considerably less dramatic.
I was able to replicate their Lowess100 smooth (of the KMean_Reconstruction series) in the Kmean tab of archived spreadsheet in first try (a Wordle eagle, so to speak) by using lowess span f=100/7368. Enabling me to comment quite precisely on similar spline smooth that they show.
the KMean_Reconstruction is linear (100% correlation) to underlying CRN shown below. The blade of the smooth begins ~1750 and, on its face, simply shows recent decades continuing trend that began ~1750.
in detail, the most recent “chronology” values (from the southerly part of Yamal) are slightly elevated from values earlier in 20th and late 19th, but no particular HS.
and, needless to say, Hantemirov and his East Anglia coauthors made NO attempt to differentiate any additional growth in Yamal resulting directly from late 20th century CO2 “greening”, though such greening is shown in Yamal along with most other locations
https://www.science.org/doi/10.1126/sciadv.aax1396
Originally tweeted by Stephen McIntyre (@ClimateAudit) on August 30, 2022.
