IPCC Fifth Assessment Report, Synthesis Report

The Synthesis Report (longer report) is based on the reports of the three Working Groups of the Intergovernmental Panel on Climate Change (IPCC), including relevant Special Reports. It provides an integrated view of climate change as the final part of the IPCC’s Fifth Assessment Report (AR5).

The Summary for Policymakers, which has been approved by all collaborating countries, follows the structure of the longer report. The AR5 SYR is divided into four topics:

- Topic 1 (Observed changes and their causes) focuses on observational evidence for a changing climate, the impacts caused by this change and the human contributions to it.
- Topic 2 (Future climate changes, risks, and impacts) assesses projections of future climate change and the resultant projected impacts and risks.
- Topic 3 (Future Pathways for Adaptation, Mitigation and Sustainable Development) considers adaptation and mitigation as complementary strategies for reducing and managing the risks of climate change.
- Topic 4 (Adaptation and mitigation) describes individual adaptation and mitigation options and policy approaches. It also addresses integrated responses that link mitigation and adaptation with other societal objectives.

In the Synthesis Report, the certainty in key assessment findings is communicated as in the Working Group Reports and Special Reports. It is based on the author teams’ evaluations of underlying scientific understanding and is expressed as a qualitative level of confidence (from very low to very high) and, when possible, probabilistically with a quantified likelihood (from exceptionally unlikely to virtually certain). Where appropriate, findings are also formulated as statements of fact without using uncertainty qualifiers.