IPCC Reference

This page is a collection of basic reference information and links about the IPCC and the  Fifth Assessment Report, launched at the end of Sept 2013.

IPCC history

The Intergovernmental Panel on Climate Change (IPCC) was set up in 1988, jointly by the United Nations (UN) and the World Meteorological Organisation (WMO). It has produced four main reports prior to the Fifth Assessment Report (AR5):

  • 1990 First Assessment Report (FAR)
  • 1995 Second Assessment Report (SAR)
  • 2001 Third Assessment Report (TAR)
  • 2007 Fourth Assessment Report (AR4)

There have been a number of suggestions recently that AR5 may be the last of these large reports. Arguments for this include the idea that the process of producing these mammoth reports is so slow that by the time they are published they are already out of date;  there is also the issue of leaks of the report. I suspect there will be much argument about this – for the IPCC to stop producing these reports could be seen as an admission that climate change is not such a serious problem as previously claimed.

In addition to the main reports, the IPCC produces other reports such as the 2012 Special Report on Extreme Events (SREX).  See IPCC timeline factsheet for more details.

IPCC structure

The IPCC is divided into three main sections, or Working Groups:

Each of these groups produces its own contribution to the full report, but not at the same time. It’s the WG1 Report that came out at the end of September. According to the IPCC timeline, the WG2 and WG3 Reports will come out in March and April 2014.

IPCC AR5 authors

The list of authors involved in writing AR5 is here.

There are three categories of authors. Each chapter has usually two “Coordinating Lead Authors” (CLAs). Then there are about ten “Lead Authors” (LAs).  There are many more “Contributing Authors”, who presumably play a more minor role and are not listed in the file linked above.

In addition to the authors, each chapter has three or four “Review Editors”. Their role is to oversee the expert review process and ensure that all comments have been handled satisfactorily by the chapter authors.

See this document, Annex 1, for full details of the roles of authors and review editors.

IPCC AR5 WG1 sections

The AR5 WG1 report was published on 30 September 2013 in a form described as “Final Draft (accepted)” with a covering disclaimer saying that it needs to be read in conjunction with a list of minor corrections.
The chapters of the AR5 WG1 Report are as follows:

Chapter 1:  Introduction
Chapter 2:  Observations: Atmosphere and Surface
Chapter 3:  Observations: Ocean
Chapter 4:  Observations: Cryosphere
Chapter 5:  Information from Paleoclimate Archives
Chapter 6:  Carbon and Other Biogeochemical Cycles
Chapter 7:  Clouds and Aerosols
Chapter 8:  Anthropogenic and Natural Radiative Forcing
Chapter 9:  Evaluation of Climate Models
Chapter 10:  Detection and Attribution of Climate Change: from Global to Regional
Chapter 11:  Near-term Climate Change: Projections and Predictability
Chapter 12:  Long-term Climate Change: Projections, Commitments and Irreversibility
Chapter 13:  Sea Level Change
Chapter 14:  Climate Phenomena and their Relevance for Future Regional Climate Change

In addition to the 14 chapters, there is the Summary for Policymakers (SPM) [broken link, see below], a Technical Summary and several annexes.

There are more details here about exactly what is covered in each chapter.  Note that this chapter structure is quite different from that of AR4, which could complicate direct comparisons between the new report and the previous one.

November:  The IPCC has now produced a glossier version of the Summary for Policymakers, which is easier to read since the figures are now in-place. There are also a few errata.

January 2014: The final version of the entire AR5 WG1 report is now available, as a rather awkward 375MB pdf file. The individual chapters of the final version can be found here.
The reviewer comments and author responses are here, along with the review editor reports, discussed in this blog post.