I have been remembering Russian historical temperature reconstructions based on tree ring data, as I have listened along to the Climate Change on Trial podcast series by investigative journalist Ann McElhinney.
Looking at the research papers* I have on file by Russians, and being reminded of the American temperature reconstruction from the Michael Mann versus Mark Steyn court case, well they are very different.
The Russian temperature reconstructions based on tree ring data generally show the cooling so evident in the instrumental record (unhomogenized/raw) for the Arctic region from 1940 through to 1975. Of course, the Russian reconstructions also include the Medieval Warm period (10th to 12th centuries).
The Americans flatten the early part of the 1,000 years long record, obliterating the Medieval Warm period, and then they use ‘Mike’s trick’ that is to graft some remodelled (homogenised) instrumental temperature data onto the end of the proxy temperature series to get a big uptick. Thus, creating what has become known as the ‘hockey stick’.
Mark Steyn has repeatedly suggested that all of this is rather fraudulent. I agree.
For his troubles, Steyn was awarded punitive damages of US$1 million in the Washington DC Superior Court just yesterday. To understand the context, consider listening along from the beginning, with the Climate Change on Trial podcast series by investigative journalist, and dear friend, Ann McElhinney.
What the Americans, including Mann, have done with the tree ring data, is much the same as the Australian Bureau of Meteorology’s homogenisation of the instrumental temperature. This mostly involves cooling the past, so the present appears warmer. I’ve written so much about this, and I will be writing some more. For context, consider my ‘Hyping Maximum Temperature’ series, that I could perhaps turn into a podcast series (Part 1 to Part 7).
Homogenisation of the Australian data that only begins in 1910, mostly obliterates the very warm decades at the beginning of the twentieth century and in the process does away with the cooling trend in the first half of the twentieth century, from about 1920 through to 1950. Considering the instrumental temperature series overall from 1910, and before they are remodelled , it is about as hot now as it was back in say 1914. Heatwaves were worse in 1896 (there are records back to 1850, unhomogenized), and summers were hotter in the late 1930s (considering the data before it is remodelled). Considering the annual averages, well, unhomogenized mean temperatures show cooling to about 1950 and then warming after this.
A problem with the last thirty years of temperature data is that it has been measured from automatic weather stations using platinum resistance probes that can be calibrated to show however many degrees hotter or cooler than a mercury thermometer might be considered convenient.
To be clear, that are at least three problems with the official Australian temperature series, 1. they are truncated (only beginning in 1910), 2. they are homogenised (cooling the data from mercury thermometers), and 3. they are unreliable at least from 1996 with the transition to a different method of measurement (platinum resistance probes in automatic weather stations).
It is the case that the Americans also remodelled (homogenize) their instrumental temperature data, as well as the proxy temperature data from tree rings, to also fit a particular and convenient narrative.
This is important to the West, or at least our financial institutions that are heavily invested in the energy transition. This energy transition, is, of course, prefaced on the assumption that temperatures continued to rise through most of the twentieth century and that they are now unprecedented. This is achieved for the official record through a combination of homogenisation (remodelling) and change of measurement system (from mercury thermometer to platinum resistance probes).
* The chart featured at the top of this post is from a paper by O.V. Sidorova et al. from the V.N. Sukachev Institute of Forestry in Russia. It was presented at the Dendro symposium in Switzerland from April 21st to 23rd in 2005.
The chart shows key features of the American hockey stick (without complete shaft) and contrasts this with a Russian proxy temperature reconstruction.
It is the case that the Russians have longer historical reconstructions based on tree ring data and continue to collect and analyse tree ring data.
The Americans have more-or-less stopped this work with tree rings, and so their reconstructions based on proxy data end in about 1965, after which they conveniently graft instrumental temperature series measured using platinum resistant probes.
I must say, at the moment, it is quite apparent that the Russians, and also the Chinese, are going much better science than anyone much in the West, at least in the areas of interest to me including rainfall forecasting and historical temperature reconstructions. It is perhaps also worth noting that reliable rainfall forecasts need accurate historical temperature reconstructions.