The decision to prepare a Fifth Assessment Report (AR5) was taken by the IPCC at its 28^th Session in April 2008. Compared to previous reports, the AR5 will put greater emphasis on assessing the socio-economic aspects of climate change and implications for sustainable development, risk management and the framing of a response through both adaptation and mitigation. It will aim to provide more detailed information on regions, including on climate phenomena such as monsoons and El Nino. To enhance overall integration some aspects including water and the Earth system, carbon cycle; ice sheets and sea-level rise; and Article 2 of the UNFCCC will be addressed in a cross cutting manner. Attention will also be given to consistent evaluation of uncertainties and risks; costing and economic analysis; and treatment of scenarios.

 

  Schedule, outlines and relevant guidance documents

Following scoping and other preparatory activities the Panel at its 31st session (Bali, Indonesia) has approved the outlines of the three Working Group contributions to the AR5, concept notes on cross cutting matters, as well as workshops and expert meetings to be held in support of the assessment process. They are compiled in the AR5 reference document (PDF).

At its 32nd session in Busan, Rep. of Korea, the Panel agreed also on the scope and outline for the AR5 Synthesis Report (SYR).
 
A short summary description of the AR5 outline, as well as of new features and areas of emphasis is provided in this AR5 leaflet (PDF).
 
The preparation of the reports follows very strict procedures, as amended at the 32nd Session of the IPCC. The full text is available in the procedures page. Main steps are summarized below. Additional guidance is provided on matters such as: Use of Literature in IPCC Reports, Role of Review Editors, and Consistent Treatment of Uncertainties.

 

  Selection of Authors and Review Editors

In early 2010, Coordinating Lead Authors (CLA), Lead Authors (LA) and Review Editors (REs) were selected by the relevant Working Group Bureaux from the nominations received from Governments and participating organisations. The Bureaux also identified experts known through their publications and works. In carrying out the selection the Bureaux aimed to identify writing teams of the highest scientific merit - capturing the needed range of institutional and disciplinary perspective and representing a range of scientific views - while ensuring both regional and gender balance, and involving the next generation of climate scientists and experts.
 
More than 830 Authors and Review Editors from 85 countries have been selected for the IPCCs Fifth Assessment Report from among 3000 nominates. In the course of the assessment process lead authors may enlist Contributing Authors. See the complete list of Authors and Review Editors, and the following statistics and regional coverage.

 

  The Review Process

IPCC Reports undergo a multi stage review process. During the first review by experts First Order Drafts are circulated to experts that have significant expertise and/or publications in particular areas of the report, and experts nominated earlier by governments and participating organizations. Those not selected to serve as a Lead Author or Review Editor for a given report traditionally serve as an expert reviewer for the particular report. Reviewers should reflect a range of scientific, technical and socio-economic views, expertise, and geographical representation.
 
During the second review by government and experts Second Order Drafts and a first draft of the Summary for Policymakers will be distributed through the government focal points to all governments, all authors and to the reviewers involved in the expert review.

 

  Lead Author Meetings

In the course of the assessment process four lead authors meetings are held by each working group. All Coordinating Lead Authors and Lead Authors get together to initiate the writing process, consult on cross cutting issues, to consider review comments received and revise the text accordingly. Review Editors participate in such meetings to ensure that all review comments are afforded appropriate consideration
 

Working Group I

Working Group II

Working Group III

 

  Expert Meetings and Workshops

A number of expert meetings and workshops have been held to support the process of preparing the Fifth Assessment Report. Proceedings of these meetings are being published.
 

2011

2010

2009

 
For reports and other documentation related to all IPCC Expert Meetings and Workshops, please see Workshops and Expert Meetings or the relevant Working Group website.

 

  Literature cut-off dates and review periods

In order to be reflected in the AR5 peer reviewed literature has to be submitted for publication well before the Second Order draft is finalized and accepted well before the final draft is circulated. Any reference that does not fulfill these criteria will be removed from the draft contribution together with the statement(s) that it supports. Working groups have provided the following cut off dates for new literature.

 

  Full AR5 Schedule

A comprehensive overview schedule which contains dates for AR5 Scoping Meetings, Sessions of the Panel to approve outlines of the reports, Lead Author meetings, review periods and cut-off dates for new literature to be assessed in the AR5 is available here.

 

  AR5 Completion Dates

AR5 contributions (Working Group reports and the Synthesis Report) will be completed by:

• Working Group I - Mid September 2013
• Working Group II - Mid March 2014
• Working Group III - Early April 2014
• Synthesis Report - End October 2014

For each Working Group report, the final full reports will be accepted and their summaries (Summary for Policymakers or SPM) approved by IPCC member governments at a Session of the Panel. At the final Session the panel will approve the Summary for Policymakers of the Synthesis Report and adopt the longer Synthesis Report.
 
For more information on IPCC procedures for acceptance/approval/adoption of IPCC reports see Procedures page.

Two IPCC Special Reports in 2011

In addition to climate assessment reports, the IPCC is publishing Special Reports on specific topics. The preparation and approval process for all IPCC Special Reports follows the same procedures as for IPCC Assessment Reports. In the year 2011 two IPCC Special Report were finalized, the Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) and the Special Report on Managing Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX). Both Special Reports were requested by governments.
 

• Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN)
  
  
  

  SRREN Press Conference in Abu Dhabi, 9 May 2011

  On May 9, the approved Summary for Policymakers of the Special Report on Renewable Energy Sources and Climate Change Mitigation was launched at a press conference in Abu Dhabi, where the 11th Session of the Working Group III took place.
   
  This report assesses existing literature on the future potential of renewable energy for the mitigation of climate change. It covers the six most important renewable energy technologies, as well as their integration into present and future energy systems. It also takes into consideration the environmental and social consequences associated with these technologies, the cost and strategies to overcome technical as well as non-technical obstacles to their application and diffusion.
   
  More than 130 authors from all over the world contributed to the preparation of IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) on a voluntary basis - not to mention more than 100 scientists, who served as contributing authors.
   
  
  • Summary for Policymakers (SPM) released on 9 May 2011
  • Press Release with key findings of the report
  • Generic Presentation
  • Videos
  • Information Note
  
   
  Additional information on the SRREN can be found at the Working Group III website for the SRREN.
   
  
• Special Report on 'Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation' (SREX)
  
  
  
  At the first Joint Session of IPCC Working Group I and II that met from 14-17 November 2011, in Kampala, Uganda the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation was approved and accepted.
   
  The report assesses the effect that climate change has on the threat of natural disasters and how nations can better manage an expected change in the frequency of occurrence and intensity of severe weather patterns. It aims to become a resource for decision-makers to prepare more effectively for managing the risks of these events. A potentially important area for consideration is also the detection of trends in extreme events and the attribution of these trends to human influence.
   
  More than 80 authors, 19 review editors, and more than 100 contributing authors from all over the world contributed to the preparation of SREX.
   
  
  • Summary for Policymakers (SPM) released on 18 November 2011
  • Press Note
  • Fact Sheet
  • Generic Presentation
  • SREX Press Conference
    
  
   
  Additional information on the SREX can be found at the Working Group II website for the SREX.

Since 1992 the IPCC has been preparing methodologies and guidelines to assist Parties to the UNFCCC and its Kyoto Protocol to prepare national inventories of greenhouse gas emissions by sources and removals by sinks. The last major publication was the "2006 IPCC Guidelines for National Greenhouse Gas Inventories". Currently the Task Force on Inventories is developing software for the 2006 Guidelines and producing other material to assist users of the guidelines. It maintains also the Emissions Factor Database (EFDB).
 
Furthermore, at its 33rd session, the IPCC decided to produce additional guidance, the "2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands", to cover both inland wetlands such as peat lands and coastal wetlands such as mangroves. Preparation of inventory guidance on wetlands has been requested by the United Nations Framework Convention on Climate Change (UNFCCC) and the IPCC hopes that the 2013 supplementary guidance will make an important contribution to future international action on wetlands. On 31 May 2011, the IPCC sent out a letter to governments and international organizations for the nomination of experts for consideration as Coordinating Lead Authors, Lead Authors and Review Editors to contribute to this work. For more information please see the TFI website.

The Task Group on Data and Scenario Support for Impact and Climate Analysis (TGICA) facilitates distribution and application of climate change related data and scenarios. The TGICA oversees a Data Distribution Centre (DDC) which provides data sets, scenarios of climate change and other environmental and socio-economic conditions, and other materials (e.g., technical guidelines on the use of scenarios) and contributes to building capacity in the use of data and scenarios for climate-related research in developing and transition-economy regions and countries. The TGICA also convenes expert meetings on an as needed basis.
 
Since the TGICA was established in 1996, a great deal has changed regarding needs and services for data and scenarios. Most significantly, the community of users has evolved from a relatively small group of researchers focusing on global-scale modeling of the impacts of climate change, to a large and diverse set of actors all across the world, including national, state/provincial, and local entities, business and industry, non-governmental organizations, and community groups, as well as through the UNFCCC Nairobi Work Programme on adaptation. The more diverse group of users has a far more diverse set of data and scenario needs, including data products more appropriate to settings with limited computational, communications, and research capacity. The process for preparation of scenarios has also changed, and has become a more open, interdisciplinary process with a larger number of interactions across the climate modeling, impacts/adaptation/vulnerability, and integrated assessment modeling communities. These changes provide new challenges and opportunities for the TGICA.
 
TGICA Membership was refreshed in the summer of 2010 (see table below). The first meeting of the reappointed TGICA was held at the National Center for Atmosphere Research in Boulder, Colorado, from 4-6 August 2010. Drs Timothy Carter (Finland) and Bruce Hewitson (South Africa) have been appointed to serve as Interim TGICA Co-Chairs for a period of two years, with Dr Rachel Warren (United Kingdom) appointed as Co-Chair elect.
 
Further information about TGICA activities and developments can be found in the Progress Report submitted to the 32nd Session of the Panel, Busan, Republic of Korea, 11 - 14 October 2010 (IPCC-XXXII/Doc. 14) and the Progress Report submitted to the 33rd Session of the Panel, Abu Dhabi, UAE, 10-13 May 2011 (IPCC-XXXIII/Doc. 19). This first report highlights the key conclusions of the group following the first meeting of the reappointed TGICA, related to the operation of the DDC, review and preparation of guidelines, and initiatives to promote capacity building. The second report outlines progress on TGICA-16 actions including a review of the DDC to identify updates needed to support the AR5 and consider other issues.
 
Currently, TGICA Members are:
 

Co-Chairs	Members		Ex Officio
Timothy Carter, Finland   Bruce Hewitson, South Africa	Daniel Bouille, Argentina   Stewart J. Cohen, Canada   Suraje Dessai, UK   Mariane Diop-Kane, France   Seita Emori, Japan   Gregory E. Insarov, Russia   Kejun Jiang, China   Tom Kram, Netherlands   Volker Krey, Austria	Won-Tae Kwon, South Korea   Jason Lowe, UK   Francisco Meza, Chile   Andy Reisinger, New Zealand   Fredrick Semazzi, USA   Allison Thomson, USA   Rachel Warren, UK (Co-chair elect)   Arthur Webb, Fiji   Fernanda Zermoglio, Sweden	Martin Juckes (DDC, BADC)   Michael Lautenschlager (DDC, MPI)   Robert Chen (DDC, CIESIN)   Pauline Midgley (IPCC, WG1 TSU)   Kristie Ebi (IPCC, WG2 TSU)   Jan Minx (IPCC, WG3 TSU)   Karl Taylor (PCMDI)   Xianfu Lu (UNFCCC)

Scenarios of potential future anthropogenic climate change, underlying driving forces, and response options have been an important component of IPCC work. In the past the IPCC coordinated the process of developing scenarios for its assessments (see AR 1990, SR 1994 and SRES 2000). In 2006 the IPCC decided that rather than directly coordinating and approving scenarios the process of scenario development should be coordinated by the scientific community. The IPCC would catalyze the timely production of new scenarios for a possible use in its AR5. To this end an expert meeting was held from 19-21 September 2007 in Noorwijkerhout, the Netherlands (Report of the meeting) which considered the plans by the scientific community and agreed representative concentration pathways. The meeting was attended by experts on integrated assessment (IAM), impacts, adaptation and vulnerability research (IAV) and climate modelling (CM). The agreement on a parallel process for scenario development and the schedule for delivering products became important for the decision by the Panel on the schedule of the AR5.
 
The early identification of a set of "Representative Concentration Pathways" (RCPs) facilitates coordination of new integrated socioeconomic, emissions, and climate scenarios. The main rationale for beginning with RCPs is to expedite the development of a broad literature of new and integrated scenarios by allowing the modeling of climate system responses to human activities to proceed in parallel to emissions scenario development.
 
Further information on scenario development and coordination with the scientific community can be found in the Progress Report submitted to the 32nd Session of the Panel, Busan, Republic of Korea, 11 - 14 October 2010 (IPCC-XXXII/Doc. 16). This report discusses the Draft Memorandum of Understanding between the Integrated Assessment Modeling Consortium (IAMC) and IPCC Working Groups II and III (IPCC-XXXII/INF.10), and the link between the IPCC and the scientific community on the scenario development process which continues now through the Co-Chairs of the Working Groups.
 
In this regard, a joint IPCC workshop of Working Groups II and III on "Socioeconomic Scenarios for Climate Change Impact and Response Assessments" was held in Berlin, Germary from 1-3 November 2010. For background and supporting material for this workshop, please see here.