Special Report on Extreme Events

Assessment Reports

IPCC Fifth Assessment Cycle


The IPCC has started the Fifth Assessment cycle, which will include the Fifth Assessment Report (AR5), Special Reports, Expert Meetings and Workshops agreed by the Plenary. A summary of the IPCC process is available online (also in PDF formats).


IPCC Fifth Assessment Report (AR5)
Fifth Assessment Report (AR5)
Writing Team Composition
A total of 1,217 nominations were submitted by IPCC Focal Points, Observer Organization representatives, and Working Group II Bureau members in response to the Call issued 15 January 2010. A total of 79 Governments submitted nominations, and 92 nationalities were represented in the candidate pool. The list of the authors of the 310 confirmed writing team members, consisting of 61 Coordinating Lead Authors (CLAs), 183 Lead Authors (LAs), and 66 Review Editors (REs), was compiled. The Working Group II Bureau is confident that it has met its goal of identifying writing teams of the highest scientific merit — capturing the needed range of institutional and disciplinary perspective — while ensuring requisite regional and gender balance, and involving the next generation of climate scientists.
Summary Statistics
Total Number of Confirmed Writing Team Members: 310
Total Number of Nationalities Represented on Writing Teams: 73
Developing Country and Economy-in-Transition Writing Team Members: 127 (41%)
Female Writing Team Members: 83 (27%)
Writing Team Members New to the IPCC Process: 187 (60%)
Young Scientists Engaged in the Process: 71 (23%)
  • "New" connotes an expert not engaged in the AR4 or the IPCC Special Report currently being prepared by Working Group II (i.e., SREX).
  • "Young" connotes an individual who obtained highest degree in 2001 or later.
Fourth Assessment Report (AR4)
Consistent with all IPCC reports, the Working Group II contribution to the Fourth Assessment Report was a comprehensive assessment of the peer-reviewed published literature and selected grey literature on climate change impacts, adaptation, and vulnerability. AR4 is available in both PDF and searchable HTML formats.
Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation
Full Special Report Available to Public Press Release

AR5 is scheduled to be finalized in 2014. As has been the case in the past, the outline of the AR5 was developed through a scoping process that involved climate change experts from all relevant disciplines, as well as users of IPCC reports, such as government representatives.

One scoping meeting to outline the AR5 was held 13-17 July 2009 in Venice, Italy. Invited experts from governments and academia discussed and developed the scope and table of contents for the three Working Groups contributions to the AR5. They also identified major issues of integration and synthesis.

During its 9th Session (26-27 October 2009), the IPCC WGII finalized and approved the chapter outlines of the WGII contribution to the AR5. The WGII outline (also available in PDF), as well as those for Working Groups I and III, was then accepted by the 31st Session of the IPCC on 29 October 2009 in Bali, Indonesia. Links to Information on the Working Group I contribution, and the Working Group III contribution to the AR5 are available.

On 15 January 2010, IPCC Focal Points and Observer Organization representatives were invited to nominate experts to act as authors and reviewers for the three Working Group contributions to the AR5. The nominations period closed on 12 March 2010, but for historical purposes the instructions remain available on line (all embedded links to the nominations system disabled). The IPCC reviewed the collected nominations, with the selection of experts carried out by respective Working Group Bureaus and finalized at the 41st Session of the IPCC Bureau (19-20 May 2010 • Geneva, Switzerland). Given the number of scientists nominated (1,217 for Working Group II alone), it was impossible to accommodate all the qualified experts put forward. In addition, the Working Group Bureaus need to consider regional and gender balance, as well as ensuring involvement of the next generation of climate scientists. Confirmations of appointments were secured within 4 weeks of the IPCC Bureau meeting, and writing teams announced on 23 June 2010. The writing process itself is underway, with Lead Authors Meetings already held for Working Groups I, II, and III.

A separate scoping meeting for the AR5 Synthesis Report was held from 25-27 August 2010. Plans are to launch this fourth volume of the AR5 and complete the assessment cycle within approximately 1 year of release of the Working Group I volume.

In addition to meetings of Lead Authors for the AR5, a number of expert meetings and workshops have been and will be held to broaden the basis for the assessment, for instance to address issues where limited peer reviewed literature exists, as well as to address cross-cutting matters. You can check the provisional WGII AR5 development schedule, and the complete set of meetings associated with current WGII commitments for more details.

Please see the WGII AR5 page for further information.

IPCC Special Reports

Working Group II also produces Special Reports, often in response to requests from the Conference of the Parties to the UNFCCC or from other environmental Conventions. Special Reports have been prepared on topics such as aviation, regional impacts of climate change, technology transfer, emissions scenarios, land use, land use change and forestry, carbon dioxide capture and storage and on the relationship between safeguarding the ozone layer and the global climate system. They are subject to the same writing, review and approval process as Assessment Reports.

Working Group II has completed preparation of the Special Report on "Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation" (SREX). SREX considers three types of extreme events: the ones for which climate change has or will amplify occurrence (e.g., floods and droughts); the ones in which trends outside the domain of climate will increase exposure or vulnerability to climate-related extremes (e.g., coastal development increasing exposure to storm surges); and new kinds of potentially hazardous events and conditions that may occur as a result of climate change (e.g., glacial lakes outburst). SREX writing teams focus on climate change and its role in altering the frequency, severity, and impact of extreme events or disasters, and on the costs of both impacts and the actions taken to prepare for, respond to, and recover from extreme events and disasters. The emphasis is on understanding the factors that make people and infrastructure vulnerable to extreme events, on recent and future changes in the relationship between climate change and extremes, and on managing the risks of disasters, over a wide range of spatial and temporal scales. The assessment considers a broad suite of adaptations, ranging from early warning to insurance to altered infrastructure and social safety nets. It also explores the limits to adaptation, the conditions that can transition adaptation into mal-adaptation, and the human and financial consequences of those limits. The assessment is intended to build durable links and foundations for partnerships between the stakeholder communities focused on climate change, adaptation, and disaster risk reduction. The UN International Strategy for Disaster Reduction (ISDR) is involved in the preparation of the report. The complete Special Report was released on March 28 2012.