Monthly Archives: June 2010

Revisiting TAR Figure 2-21, part 1: Another false claim from Steve McIntyre

In the “climategate” din, one accusation is shouted perhaps louder and more often than any other: the so-called “trick” supposedly played by IPCC lead author Michael Mann to “hide the decline” in Keith Briffa’s Northern Hemipshere extra tree-ring proxy-based reconstruction, featured along with three others in a key chart in the 2001 WG1 Third Assessment Report (TAR).

According to self-appointed climate science auditor Steve McIntyre, Mann took it on himself to truncate Briffa’s data set and replaced the deleted data with instrumental temperature data, thus creating less of a drop at the end of the resulting smoothed chart. But a closer examination shows the evidence for instrumental “padding” is far from certain. And the difference engendered between different possible “padding” values is minimal in any case.

Even worse, the key element of McIntyre’s narrative, namely the claim that Mann himself truncated Briffa’s data set, is false. In fact, it turns out that the actual data set used by Mann (as sent by Tim Osborn on Keith Briffa’s behalf) contains values only up to 1960 – exactly as in the figure produced in TAR. So once again, we have another egregiously false accusation from Steve McIntyre, one that has been echoed by McIntyre acolytes and CruTape Letters authors Steven Mosher and Thomas Fuller.

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Mike Hulme sets Lawrence Solomon and Marc Morano straight

The latest false scandal in climate science hit the blogosphere over the weekend. National Post columnist Lawrence Solomon [not to be confused with atmospheric chemist and IPCC WG1 chair Susan Solomon] wrote a column with the outlandish claim:

The UN’s IPCC misled the press and public into believing that thousands of scientists backed its claims on manmade global warming, according to Mike Hulme, a prominent climate scientist and IPCC insider.

Charges of  a “phony UN IPCC consensus” are already reverberating on contrarian blogs around the world, thanks to the quick efforts of climate science disinformation specialist Marc Morano.

But now Mike Hulme, a professor of climate change at the University of East Anglia, has set the record straight. His “correcting and clarifying” statement is unambiguous in its disavowal of Solomon’s and Morano’s misinterpretation:

I did not say the ‘IPCC misleads’ anyone – it is claims that are made by other commentators, such as the caricatured claim I offer in the paper, that have the potential to mislead.

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Michaels and Knappenberger’s World Climate Report: “No warming whatsoever over the past decade”

The most recent twist on the “global warming has stopped” meme is the citation of highly respected researchers in support of that incorrect, yet somehow persistent proposition. Once again, the charge is being led by leading climate contrarian Patrick Michaels, ably assisted by Paul “Chip” Knappenberger.

Earlier this year, Michaels’ World Climate Report cited two papers (Easterling and Wehner, 2009 and Solomon et al 2010) as demonstration of mainstream acknowledgment that there has been “no warming whatsoever over the past decade”.

But a closer examination shows that Solomon et al  were actually citing the earlier Easterling and Wehner, a paper itself deeply critical of skeptic “cherrypicking” of short-term trend start points. Even worse, discussion of these two papers at World Climate Report contains some of the most egregious examples of quote mining and distortions of others’ work I have ever seen.

To be sure, Solomon et al do acknowledge that warming in the 2000s has been less than projected by the IPCC model ensemble and shows flattening relative to the previous decade (hardly controversial propositions). But their analysis of smoothed observations and decadal model projections implicitly rejects the contrarian obsession with short-term trends, and points the way towards a more compelling characterization and comparative analysis of model projections and observations.

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