On Thursday, a writer named Alec Rawls posted a leaked draft version of a portion of the upcoming Fifth Assessment Report (AR5) by the Intergovernmental Panel on Climate Change (IPCC) and claimed that the report acknowledges “strong evidence for enhanced solar forcing.” He claimed that the IPCC’s admission “changes everything” and that “climate alarmists can’t continue to claim that warming was almost entirely due to human activity over a period when solar warming effects, now acknowledged to be important, were at a maximum.” Rawls’s comments are based on brief excerpts in AR5 that mention a hypothetical connection between galactic cosmic rays (GCRs) and some aspects of climate.

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Critics of man-made global warming called the release of the leaked document “game-changing” and said the revelation means that “the case for man-made global warming is looking weaker by the day and that the sun plays a much more significant role in ‘climate change’ than the scientific ‘consensus’ has previously been prepared to concede.”

On Friday, environmental scientist Dana Nuccitelli wrote at SkepticalScience that

If the IPCC was to report that the sun is a significant player in the current rapid global warming, that would indeed be major news, because the body of peer-reviewed scientific literature and data clearly show that the sun has made little if any contribution to the observed global warming over the past 50+ years.

“So why would the latest IPCC report contradict these studies when its purpose is to summarize the latest and greatest scientific research?” Nuccitelli asks “The answer is simple — it doesn’t. Rawls has completely misrepresented the IPCC report.” Nuccitelli goes on to show that AR5 is in fact “consistent with the body of scientific literature in stating that research indicates GCRs are not effective at seeding clouds and have very little influence on global temperatures.” He says that “The leaked IPCC report is entirely consistent” with the consensus conclusion that “human greenhouse gas emissions, not solar activity or galactic cosmic rays, are causing global warming.”

The Australian Broadcasting Corporation (ABC) interviewed Steve Sherwood, director at the Climate Change Research Centre at the University of New South Wales. Sherwood is one of the authors of the chapter of AR5 that was leaked Thursday. When asked if the report “confirms a greater role for solar and other cosmic rays in global warming,” Sherwood replied,

Oh that’s completely ridiculous. I’m sure you could go and read those paragraphs yourself and the summary of it and see that we conclude exactly the opposite, that this cosmic ray effect that the paragraph is discussing appears to be negligible.

Rawls obtained the draft AR5 report by registering as an “expert reviewer.” IPCC releases drafts to large numbers of such reviewers in order to obtain broader commentary in advance of the release of its final reports. Environmental journalist Graham Readfearn explains that the term “expert reviewer” does not imply scientific credentials; in fact, “practically anyone can register for these positions using an online form.” On receiving a copy of the draft, a reviewer agrees not to cite, quote, or distribute the report. Rawls justifies his leaking the report by claiming that the “public’s right to know” trumps any confidentiality agreement he made and that the AR5 drafts “ought to fall within the reach of the Freedom of Information Act.”

In a Friday statement, the IPCC press office said that the unauthorized posting of the draft report “interferes with the process of assessment and review” and that the organization would “continue not to comment on the contents of draft reports, as they are works in progress.” Posting of draft reports, says IPCC, “may lead to confusion because the text will necessarily change in some respects once all the review comments have been addressed.” The draft reports “were provided in confidence to reviewers and are not for distribution.” In making the drafts public, Rawls “broke the terms of the review.”

Photo credits: NASA and John LeGear

+ Intergovernmental Panel on Climate Change