February 2nd, 2007:  In the most thorough and complete assessment of the science of global climate change, the Intergovernmental Panel on Climate Change (IPCC) wrapped up six years of work in Paris with the release of the first section of its Fourth Assessment Report, which describes the progress in understanding of the human and natural drivers of climate change, observed climate change,  and estimates of projected future climate change. 

The report built on the analysis of the IPCC Third Assessment report in 2001, but spoke with much greater confidence that human activity and the burning of fossil fuels is what is causing the warming.   According to the summary, it is "very-likely" (i.e. > 90% probability of occurrence) that human-caused emissions are the main factor in warming since 1950.
(photo courtesy Greenpeace)

Click here to view statements on the IPCC Working Group I release from various organizations

Key Points from the Report:

• Warming of the planet is unequivocal, as evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level
• The report confirms that key heat-trapping gases in the atmosphere are at their
  highest levels in the past 650,000 years
• Eleven of the last twelve years (1995 -2006) rank among the 12 warmest years in the instrumental record of global surface temperature (since 1850), with Scientist's best estimate for temperature rises of 3.2-7.1 degrees Fahrenheit by 2100.
• Scientists predict an increase in sea levels  of 7-23 inches by the end of the century. An additional 3.9-7.8 inches are possible if recent melting of the polar ice sheets continues.

Click here to download the Summary for Policy Makers of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change