IPCC WorkiNG group II

Summary Description of the IPCC Process


December 2009


The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the United Nations Environmental Programme (UNEP) and the World Meteorological Organization (WMO) to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation.


The main activity of the IPCC is to provide at regular intervals Assessment Reports on the physical basis of climate change, its impacts, and adaptation and mitigation options to avoid, prepare for, and respond to current and projected impacts. Each Working Group contribution to an Assessment Report consists of individual Chapters, a Technical Summary and a Summary for Policymakers. "Climate Change 2007" is the IPCC's Fourth Assessment Report and was published in 2007. The IPCC is currently undertaking the IPCC Fifth Assessment Report, which will be published in 2013/2014. The preparation of IPCC Assessment Reports follows strict and clearly defined procedures which are described in detail at: http://www.ipcc.ch/pdf/ipcc-principles/IPCC Procedures.pdf.


The assessment process begins with a Scoping Meeting attended by scientific experts whose task it is to outline the report. The IPCC Bureau selects the experts attending the Scoping Meeting after an open call for nominations to Governments and IPCC observer organizations. The Bureau consists of experts elected by an IPCC Plenary composed of all WMO and UNEP member nations. The outline is then approved by Working Group Sessions and endorsed by the Plenary. A call for nominations of authors for the report is sent out to Governments and observer organizations. The individual Working Group Bureaus select the authors for respective contributions to the Assessment Report, ensuring that the composition of the author teams reflects a range of views, scientific expertise and geographical diversity. Over the ensuing 3-4 years, writing teams collaborate on drafting chapters — including four Lead Author meetings, plus chapter meetings as necessary. The author teams prepare two externally reviewed drafts and then a final version of their respective chapters. All chapters undergo a rigorous writing and open review process to ensure consideration of all relevant scientific information from established journals with robust peer review processes or from other sources which have undergone robust and independent peer review. Additional procedures are provided for information found in sources that have not been published or peer-reviewed. In these cases, authors and chapter teams should critically assess and review the quality and validity of each source before incorporating results.


The First Order Draft is subject to a formal Expert Review, where any expert is encouraged to comment on all aspects of the draft, including, but not limited to, issues of interpretation, missed literature, and presentation. Author teams must make a written response, explaining how they responded to each comment in developing the next draft. A Second Order Draft is compiled based on the comments received during the Expert Review. This draft undergoes a second combined formal Expert and Government Review. Author teams have to react to the second round of review comments as well and prepare the final draft, taking into account all the comments received. The entire review process is overseen by a team of 2-3 independent Review Editors for each chapter, whose role is limited to overseeing the reviews, ensuring the thoroughness of the responses. All the AR4 review comments and responses by the author teams are available online (see http://ipcc-wg2.org/publications/AR4/ar4review_access.html for links to the AR4 review comments).


In parallel, the Summary for Policymakers and the Technical Summary are prepared by authors selected from chapter writing teams. The Summary for Policymakers and the Technical Summary undergo a formal Expert and Government Review and are revised based on the review comments. Again, 2-3 Review Editors oversee the review process for the Technical Summary. The Summary for Policymakers is then distributed to the Governments for final comment. The Summary for Policymakers undergoes a line-by-line approval process by Governments during a multi-day meeting. The Governments must reach consensus before text is approved. After the Working Group Session approves the Summary for Policymakers, the IPCC Plenary then accepts the entire underlying Report (including the individual chapters and Technical Summary).


The following provides some numbers relevant to the process for the Working Group II Contribution to the IPCC Fourth Assessment Report, Climate Change 2007: Impacts, Adaptation, and Vulnerability:


The Report
Two Scoping Meetings to outline 20 Chapters
176 Lead Authors and 46 Review Editors from 72 countries
232 Contributing Authors from 48 countries
Over 8,000 peer-reviewed publications cited
The Summary for Policymakers was approved line-by-line by all WMO and UN member governments participating in the WG approval session
The Reviews
Over 40,000 comments from:
1181 Expert Reviewers, from 92 countries
41 Governments
WGII AR4 Drafts, Review Comments and Author Team Responses are available here