The Working Group II contribution to the AR5 (WGII AR5) has 30 chapters, a Technical Summary, and a Summary for Policymakers. The WGII AR5 considers the vulnerability and exposure of human and natural systems, the observed impacts and future risks of climate change, and the potential for and limits to adaptation. The chapters of the report assess risks and opportunities for societies, economies, and ecosystems around the world.
The 242 Lead Authors and 66 Review Editors involved in the WGII AR5 are experts from around the world in disciplines including natural and physical sciences, engineering, social sciences, public policy, and development and management sciences. 436 additional experts were invited by the Lead Authors of the report to be Contributing Authors and to provide specific knowledge or expertise in particular areas. Lead Authors and Review Editors were
selected for their scientific and technical expertise in the areas covered by the approved chapter outlines for the WGII AR5 from lists of experts nominated by governments and IPCC observer organizations. Regional and gender balance was also considered, as well as ensuring the involvement of experts who had not worked on previous IPCC assessments. In the course of their work on the WGII AR5, authors spent countless volunteer hours, participated in hundreds of web-based meetings, and attended four Lead Author meetings to assess thousands of scientific and
technical sources. Over 12,000 references are cited in the WGII AR5.
Multiple stages of review are an essential part of the IPCC process. Both expert reviewers and governments are invited at different stages to comment on the scientific and technical assessment and the overall balance of the drafts. The review process includes worldwide participation, with hundreds of experts reviewing the accuracy and completeness of the scientific assessment contained in the drafts.