On Sunday (November 2nd), the IPCC released the final installment of its Assessment Report 5 (AR5), the Synthesis Report. I’ve written about the IPCC and its publications before, but this seems a good time to offer a recap before addressing the new report itself.
The IPCC is the Intergovernmental Panel on Climate Change, a body that exists to brief the UN (and everybody else) on climate change. It conducts no new research and does not advocate specific policies. Instead, it compiles existing research into various types of reports so that the people responsible for drafting policy can get thorough, accurate information without having to read thousands of scientific papers themselves. The most extensive of the IPCC’s reports. and the real heart of its labor, are the Assessment Reports, which summarize the entire body of scientific knowledge on the subject–what we’re dealing with now and what we can expect for the future under various scenarios.
The IPCC is subdivided into three main Working Groups, each of which focuses on a particular aspect of climate change. The Assessment Report as a whole consists of each Working Group’s report, plus a final Synthesis Report at the end. Over the past year and a half, the IPCC has released one of these reports every few months. Each of these installments also has an associated Summary for Policymakers, and each has gone through several drafts, some of which were leaked to the press. Over the past two years or so, all of the many news stories we’ve heard on recently released IPCC reports have been installments, summaries, or leaked drafts of this one report–the AR5.
Each of these installments has attracted controversy, including accusations from both climate deniers and advocates that the IPCC must somehow be on the take, or at least bowing to political pressure to present a less accurate, more convenient result. There are three good reasons to believe that these accusations are baseless:
- If the IPCC were lying for money or politics, wouldn’t it have done a better job of pleasing its patron? In point of fact, it has received criticism from both sides, suggesting that it is beholden to neither
- If someone in the IPCC wanted to lie for money, he or she would not have joined the IPCC in order to do it; members serve without pay. There are much more lucrative options out there
- There are simpler explanations for the concerns of both sides:
- Climate advocates have complained that the AR5 presents a misleadingly rosy view, leaving out a lot of the more dire possibilities we face. The explanations involve the rules of the IPCC, especially the fact that only papers published before a certain cut-off date could be considered for the report. Between how long it takes for research to find its way into publication and the IPCC’s own lead-time, the AR5 comes off the presses almost five years out of date. Given that what we know about global warming keeps getting worse, old news is always comparatively bright.
- Climate deniers have complained that AR5 is extreme or alarmist–in that they are right, inasmuch as the truth is extremely alarming.
The entire AR5 is or will soon be publicly available. For those who do not wish to read hundreds of pages of very dense and technical text, there are also the Summaries for Policymakers. The Summary for the recently released Synthesis Report is available here. It, too, is dry as toast, but it’s fairly accessible and only 40 pages long.
I’m not going to summaries the Synthesis Report in detail, since it is largely a summary of the three earlier reports, which I’ve already summarized. The main points are that climate change is real, mostly being caused by human activity, and very, very dangerous. If we do not drastically cut greenhouse gas emissions by 2050, and cut them to zero by the end of the century, cataclysm will be unavoidable.
But the report is a wealth of information for those with an interest in the subject–almost all of the figures and ideas we’ve been seeing in climate-related internet memes, in one place, from a reliable source. It is worth reading. There are some places that might be unintentionally misleading for the general reader, though. For example:
The period from 1983 to 2012 was likely the warmest 30-year period of the last 1400 years in the Northern Hemisphere, where such assessment is possible (medium confidence). [Emphasis original]