Assessment Report of Working Group I, II and III

The Working Group I contribution provides a comprehensive assessment of the physical science basis of climate change. The report includes a detailed assessment of climate change observations throughout the climate system; dedicated chapters on sea level change, biogeochemical cycles, clouds and aerosols, and regional climate phenomena; extensive information from models, including near-term and long-term climate projections; and a new comprehensive atlas of global and regional climate projections for 35 regions of the world.

The Working Group II contribution 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 Working Group III contribution assesses the options for mitigating climate change and their underlying technological, economic and institutional requirements. It transparently lays out risks, uncertainty and ethical foundations of climate change mitigation policies on the global, national and sub-national level, investigates mitigation measures for all major sectors and assesses investment and finance issues.