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Showing posts with the label proxy reconstruction

Ljungqvist 2010's "Hockey Stick" Paper

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About 15 years ago a paper was published[1] that included a proxy reconstruction of extratropical Northern Hemisphere temperatures for the last 2000 years. The graph included in the paper sometimes gets adapted by contrarians to give the impression that the Medieval Warm Period was warmer than today. Here's one example: The claim is then made that this is evidence or proof that Mann's hockey stick was a fraud, and scientists like Mann were actively trying to erase the Medieval Warm Period. Of course there are a few problems with this conclusion, beginning with the fact that it appears these people haven't even read the abstract of Ljungqvist's paper: Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. ad 300–800, despite significant differences in both data coverage and methodology. Rather...

More Nonsense from Javier VinĂ³s on Paleoclimate

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Today I saw a post  by  Javier VinĂ³s on X that shows just how far he will go to lie about what paleoclimate studies teach us about our current warming trend. The text of the post w as, "I can lose weight at 1 kg/week, 4 kg/month. But not 52 kg/year or 521 kg/decade. Each kg is harder than the one before. Climate change extrapolation in models and alarmism is also wrong. The rate of warming will decrease over time until it stops." Then he shows this graph from Moberg et al 2005: VinĂ³s' Nonsense On Curry's blog some years ago he says that the red curve is his take on Eddy cycles with a 980-year periodicity. He calculates no forcing value for these cycles, nor does he justify at all the scale he used for the sine wave's amplitude. He appears to have just calculated a sine wave with an amplitude that matches Moberg 2005 and set to a periodicity of 980 years. The clear implication of his post and graph putting both of these together is that it's impossible for th...

Tony Heller's Proxy Trick

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Recently I've seen people posting the following graph from Tony Heller, which is intended to show a cooling trend in temperatures following the 1940s and suggest that the "start of the satellite record" begins when temperatures are at their low point. Heller's graph is unsourced except for being called "Briffa's Reconstruction." This graph has shown up on Twitter, and so far I haven't seen any one identify the source of this data or even what the data represents. However, I was able to determine that up through 1960, the data is identical to Briffa 2001[1], and the data is on an Excel spreadsheet on an FTP site maintained by NOAA for plate 3 of Briffa's paper. The same site also has regional data that includes years following 1960 (plate 2 in Briffa's paper), but Briffa is clear that the post-1960 data does not have a clear temperature signal. Briffa writes, "The period after 1960 was not used to avoid bias in the regression coefficients...