IPCC Fourth Assessment Synthesis Report: Climate Change 2007

This Synthesis Report is based on the assessment carried out by the three Working Groups of the Intergovernmental Panel on Climate Change (IPCC). It provides an integrated view of climate change as the final part of the IPCC’s Fourth Assessment Report (AR4).

It draws together and integrates for the benefit of policy makers and those from others professions, up to date policy-relevant scientific, technical and socio-economic information on climate change. This report is intended to assist governments and other decision-makers in the public and private sector in formulating and implementing appropriate responses to the threat of human-induced climate change.

The scope of the Synthesis Report includes the information contained in the three Working Group contributions to the IPCC AR4, the Working Group I report on 'The Physical Science Basis', the Working Group II report on 'Impacts, Adaptation and Vulnerability' and the Working Group III report on 'Mitigation of Climate Change'. It also draws on other IPCC reports, in particular recently published IPCC Special Reports.

The Synthesis Report addresses a range of broad policy-relevant questions, structured around 6 topic headings agreed by the Panel, and it gives careful attention to cross-cutting themes.

* Topic 1 brings together information from Working Groups I and II on observed changes in climate and the effects of past climate change on natural systems and human society.

* Topic 2 addresses causes of change, considering both natural and anthropogenic drivers of climate change. It analyses the chain including greenhouse gas emissions and concentrations, to radiative forcing and resultant climate change, and evaluates whether observed changes in climate and in physical and biological systems can be attributed to natural or anthropogenic causes. In providing that information it draws on information contained in all three Working Group contributions to the AR4.

* Topic 3 presents information from the three Working Group reports on projected future climate change and its impacts. It provides updated information on emissions scenarios and projected future changes in climate in the 21st century and beyond, and describes the projected impacts of future climate change on systems, sectors and regions. Special attention is given to issues of human well-being and development.

* Topic 4 describes adaptation and mitigation options and responses as assessed in the reports of Working Groups II and III, and the inter-relationship of climate change and response measures with sustainable development. The focus of this topic is on response measures that can be implemented by 2030. Technologies, policies, measures and instruments as well as barriers to implementation are addressed along with synergies and trade-offs.

* Topic 5 covers the long-term perspective and analyses scientific, technical and socio-economic aspects relevant to adaptation and mitigation, consistent with the objectives and provisions of the United Nations Framework Convention on Climate Change (UNFCCC). It places decision-making about climate change in a risk management perspective, paying attention to broader environmental and integration issues. The topic describes emissions trajectories for stabilisation of greenhouse gas concentrations at various levels and associated temperature increases, along with information about the costs of mitigation, required technology development and deployment, and avoided climate impacts. It also explores in detail five main reasons for concern regarding climate change, which it finds have become stronger due to new knowledge since the TAR.

* Topic 6 highlights robust findings and key uncertainties.

While the Synthesis Report is a largely self-contained document, it needs to be viewed in the context of the other volumes of 'Climate Change 2007' and it is recommended that for further details the contributions of the three Working Groups be consulted.

More assessments reports of the IPCC are found  here.