The Third Assessment Report (TAR) of the United Nations Intergovernmental Panel on Climate Change (IPCC).

The Working Group I contribution focuses on the science of climate change. It covers the physical climate system, the factors that drive climate change, analyses of past climate and projections of future climate change, and detection and attribution of human influences on recent climate.
The Working Group II contribution focuses on the environmental, social, and economic consequences of climate change and potential adaptation responses. It covers the sensitivity, adaptive capacity, and vulnerability of natural and human systems to climate change, and the potential impacts and adaptation options at regional and global scales.
The Working Group III contribution focuses on the mitigation of climate change. It covers the technological and biological options to mitigate climate change, their costs and ancillary benefits, the barriers to their implementation, and policies, measures and instruments to overcome these barriers.