On 3 January 2014, climate scientist Michael Mann went on MSNBC's 'All In With Chris Hayes' to explain that yes, it can still get cold in the winter even though climate change is real. There can even be ice and snow. Seasons still happen. There’s no shortage of evidence to support human-caused climate change, and none of it means weather is over. Photo: MSNBC

25 February 2014 (Climate Science Watch) – Attempts to discredit Prof. Mann and confuse the facts about his defamation lawsuits keep popping up and circulating in the blogosphere. Here we comment on issues pertaining to the conclusions of the Muir Russell investigation, Mark Steyn's response and counterclaims, and the status of the case in Canada against Tim Ball.

The first allegation is that Dr. Mann made false statements in a brief submitted to the District of Columbia Superior Court regarding Sir Muir Russell’s review of the UK Climatic Research Unit (CRU) emails (i.e., as part of the so-called Climategate investigation). Specifically, the allegations purport to show that Mann intentionally altered a quote from the Russell report in order to support the contention that Russell’s inquiry exonerated Mann.

The Muir Russell report focused on the conduct of scientists at the CRU, which is based at the University of East Anglia. The investigation addressed several issues, including issues on which CRU scientists collaborated with Mann and other non-CRU members of the climate science community. Sir Muir Russell reviewed 140 e-mails authored by Mann, plus numerous other e-mails authored by other scientists.  The issues examined by Russell included whether scientists had ignored potential problems in tree-ring data that may undermine the hockey-stick graph and whether CRU, in consultation with Mann, attempted to diminish the significance of the Medieval Warm Period. Russell’s report was unequivocal in its conclusion that the rigor and honesty of the collaborating scientists was not in doubt.

While the Muir Russell report's conclusions specifically referred to the CRU scientists, it seems reasonable to us to say that it found nothing dishonest or fraudulent in their collaboration with Mann and other scientists. That's the bottom line. The allegation against Mann appears to be something of a tempest in a teapot -- or, to mix metaphors, a grasping at straws. The report isn't a comprehensive  investigation of Mann's work, and no one purports that it is -- but then it is only one of numerous investigations, from various angles, that all reached similar conclusions.

Looking at the bigger picture: The obsession among contrarians and denialists with trying to overthrow climate science by discrediting seminal early paleoclimate research by Mann and his colleagues in the 1990s is about politics, not science. Paleoclimate research has continued to advance during the past 15 years. Mann and numerous other researchers have continued to add to the peer-reviewed scientific literature, and here's where things stand as of the IPCC's Fifth Assessment Report, issued last year:

For average annual [Northern Hemisphere] temperatures, the period 1983–2012 was very likely the warmest 30-year period of the last 800 years (high confidence) and likely the warmest 30-year period of the last 1400 years (medium confidence). This is supported by comparison of instrumental temperatures with multiple reconstructions from a variety of proxy data and statistical methods, and is consistent with AR4.

– IPCC AR5, Working Group I, Paleoclimate chapter, p. 386

The critics of the original 'hockey stick graph' might want to spend some time looking at the actual advance of scientific understanding in this area of research -- which is just one piece of the complex mountain of research on human-caused climate change. [more]

Setting the record straight on misleading claims against Michael Mann


  1. The Crater Lake Hermit said...

    Translation: The contrarians and denialists are liars and full of bull manure.  


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