Jun 13, 2010

Cross Examining the IPCC

James Johnston has been a law professor at the University of Pennsylvania since 1995. For most of that time, he has also been the director of an environmental law program. Dozens of his articles have appeared in academic journals, and he has received an award for teaching excellence.

A few weeks ago, Johnston uploaded an 82-page working paper titled "Global Warming Advocacy Science: a Cross Examination" to a scholarly depository [abstract & download page here]. Within its pages he performs a task lawyers undertake as a matter of course: he cross-examines an expert witness.

The expert witness is the Intergovernmental Panel on Climate Change - or IPCC (which Johnston describes as representing the views of the climate change "establishment"). He points out that while trial lawyers often lack scientific training, this doesn't stop them from educating themselves about relevant technical issues and then asking tough questions.

In essence, Johnston performs a simple reality-check. Since many politicians, economists, regulators, and legal scholars swallow IPCC pronouncements whole - and then propose costly measures in response - Johnston makes an obvious point:
[O]ne would suppose that before such policies are undertaken, it would be worthwhile to verify that the climate establishment's view really does reflect an unbiased and objective assessment...such verification means comparing what the IPCC has to say about climate science with what one finds in the peer-reviewed climate science literature, and then questioning apparent inconsistencies..." (p. 8 of the PDF, numbered as p. 5)

Johnston's paper introduces a helpful concept. Are IPCC reports equivalent to legal briefs - or legal memos? A legal brief is a document intended to persuade the reader of a particular point of view. Legal memos, on the other hand, strive to objectively provide all the available facts - both pro and con (see the definition at the bottom of this page).

Johnston says he was surprised to discover that "on virtually every major issue in climate change science" IPCC reports "systematically conceal or minimize what appear to be fundamental scientific uncertainties." In other words, while the IPCC's mandate is to be balanced and objective (like a legal memo), Johnston argues its reports have more in common with legal briefs. (p.9/6)

He acknowledges that the authors in many IPCC chapters (the 2007 report had a total of 44 chapters), did an honest job of disclosing "what is known and what is unknown...in their particular field." But the bigger picture, and the one presented in the IPCC's summaries, amounts to an effort to "marshal evidence in favor of a predetermined" set of beliefs - that human-produced greenhouse gas emissions will cause catastrophic global warming and must therefore be curtailed (p.10/7).

In other words, unlike a good detective who first assembles the evidence and then draws conclusions, the IPCC leadership knew the culprit was carbon dioxide well before it began its investigation. The only evidence it then took seriously was evidence pointing toward this conclusion.

These findings, Johnston says, don't prove that the views of the climate establishment are in error. Who is right and who is wrong about climate change is a separate debate - and will likely only be known decisively once a considerable amount of time has passed.

The problem is that if your mandate is to produce an objective report and you instead ignore, minimize, and conceal evidence that happens to undercut your preconceived opinions, you've betrayed the public's trust.

This is morally wrong and renders you untrustworthy. Duh.


Johnston's 82-page PDF has also been directly posted online (saving you the step of downloading it). I've assigned its web-address an easy-to-remember short URL:



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