If you made it past the headlines about the government shutdown and looming default on our national debt, you may have read about a new report from the Intergovernmental Panel on Climate Change (IPCC).  If you want to better understand the current state of climate science, you should delve into this report.  Unfortunately, if you start reading the report without any context, it’s a bit daunting.  So, to make things easier, here is some background on what you will be reading.

First of all, these folks have been at this for a while.  The United Nations Environment Programme and the World Meteorological Organization launched the IPCC in 1988 to study climate change.  The IPCC, however, does not do original research; instead, it reviews and compiles the work of climate scientists into one comprehensive report in an effort to capture the scientific consensus on climate change.  Science continues to evolve, of course, so it is not really possible to arrive at one final and definitive report.  Still, the IPCC’s work carries serious weight and a fresh report from the IPCC is like a new edition of the climate science textbook.

The newly released material is part of the IPCC’s Fifth Assessment Report (AR5) on climate change.  Climate change is a broad topic, of course and the AR5 is actually a series of reports that the IPCC is rolling out this year and next.  (The IPCC released the Fourth Assessment Report in 2007.)  The first portion of the AR5 being released is the Working Group I report focusing on the physical science basis of climate change.  The Working Group II report will cover impacts, adaptation, and vulnerability, and the Working Group III report focuses on mitigation.  The IPCC boasts that the Working Group I report has 259 authors and cites over 9,200 scientific publications.  Together with a technical summary, appendices, etc., this first part of AR5 totals over 2,000 pages.  And it isn’t exactly light reading.

While the full Working Group I report has been “submitted” to the IPCC, the bulk of it has not yet been “approved” and remains subject to further revisions.  Nonetheless, you can access the draft online.

The portion of the report that was released in “approved” form on September 27 is the Summary for Policy Makers (SPM).  Oddly, though, the tables and figures in the SPM remain subject to further copyediting and are inconveniently stuck in the back of the report.  (Did someone miss a deadline here?)

The SPM is the report making news and is what you should be reading.  It is a dense 36 pages but manageable if you are a dedicated reader.  You can find the Summary for Policy Makers – and the full draft of the Working Group I report – here.