The Intergovernmental Panel on Climate Change (IPCC) is universally recognized as the world's most authoritative voice on the science of climate change.

Established by the United Nations, the role of the IPCC is to assess the scientific, technical and socio-economic information relevant to climate change, as well as its potential impacts and options for adaptation and mitigation. The IPCC's assessment reports are benchmarks in humanity's understanding of climate change.

In February, 2007, the IPCC released a summary of the contribution of Working Group I to the Fourth Assessment Report titled Climate Change 2007: The Physical Science Basis. This most recent research from the IPCC concludes that global warming is "unequivocal" and that human activity is the main driver of this warming, asserting with near certainty — more than 90 percent confidence — that carbon dioxide and other heat-trapping greenhouse gases from human activities have been the main causes of warming since 1950.

In April, 2007, the IPCC released the Working Group II Summary for Policymakers that evaluates “Climate Change Impacts, Adaptation and Vulnerability". This report highlights the opportunity to limit the risks and costs of climate change through both emissions reductions and coping strategies to contend with the near-term impacts of unavoidable warming.

On May 4, 2007, the Summary for Policymakers of Working Group III to the Fourth Assessment Report was approved, detailing strategies needed for the Mitigation of Climate Change. Many of the solutions presented in the report focus on existing technologies such as switching from coal-fired power to renewable energy sources, improving energy efficiency in buildings and introducing more effective economic incentives.

The complete Fourth Assessment Report will be released by the IPCC in stages throughout 2007. You can follow the release of each assessment report here. 

Key findings of the Third Assessment Report, from 2001, are still available for review and are divided into three sections:

• Working Group I assesses the scientific aspects of the climate system and climate change.
  
  
• Working Group II assesses the vulnerability of socio-economic and natural systems to climate change, consequences of climate change, and options for adapting to it.
  
  
• Working Group III assesses options for limiting greenhouse gas emissions and mitigating climate change.
  

Interactive Figures:

A map of the world with summaries of key concerns by region

How water resources will be affected by climate change in North America

Examples of projected increases in extreme events and their effects