Lastest IPCC assessment of future climate changes leaked in draft form

We knew the coming Fifth Assessment Report of the IPCC, which I discussed briefly here, would make waves–just not this soon.  The Intergovernmental Panel on Climate Change produces these assessments every five to seven years.  They are the most rigorous and prominent summaries of the science of climate change, crafted by leading scientists from many nations and used by policymakers worldwide.  A draft of the Working Group I report, which is not due in final form until late next year, was leaked today by a climate skeptic who had apparently seen drafts as a (self-appointed) reviewer.  Working Group I looks at the physical, scientific aspects of the climate system and climate change, including observed greenhouse gas concentrations and projections about temperature changes and other changes to come.

So what’s the big, scandalous reveal in the draft?  The leak is available at and I’ve looked at its summary for policymakers.  To me, there’s no there there.  (E&E has a summary of some of its main findings here (paywall)).  Language on observed effects, the drivers of those effects, and future projections is explicitly stronger than it was in AR4, the last such report, released in 2007.  Because the draft is not intended to be quoted, I won’t go into more detail.

Atmospheric scientist Alex Hall is here at UCLA and is a lead author of this Working Group I report. His reaction to the leak seems dead-on to me:  “Each iteration of the report has been available to anyone who signs up to review it, so in some sense it has been publicly available for a while now.  But the leak does muddy the waters in the eyes of the public.  And perhaps that is the intent.”

The IPCC’s statement today in response to the leak is here.  It reiterates that “the cut-off date for peer-reviewed published literature to be included and assessed in the final draft lies in the future (15 March 2013). The text that has been posted is thus not the final report.”

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About Cara

Cara Horowitz is the co-executive director of the Emmett Institute on Climate Change and the Environment at UCLA School of Law. The Emmett Institute was founded as the f…

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