An international panel of scientists said Friday that human activity is the dominant cause of the global warming observed since the 1950s. Calling man-made warming "extremely likely," the Intergovernmental Panel on Climate Change (IPCC) issued the strongest proclamation to date about the state of the climate system.
In its previous assessment, in 2007, the U.N.-sponsored panel said it was "very likely" that global warming was man-made.
The IPCC said a growing body of observations, climate models, and research contributed to their conclusion. Scientists now have a clearer understanding of the climate system and improved models to analyze the impact of rising temperatures, according to the report.
The full 2,000-page report won’t be released until Monday, but the summary for policymakers with the key findings was published Friday and included key findings:
- The IPCC raised its projections of the rise in sea levels to 10-32 inches (26-82 centimeters) by the end of the century. The previous report predicted a rise of 7-23 inches (18-59 centimeters).
- A decrease in the estimate of how sensitive the climate is higher CO2 concentrations. In 2007, the IPCC said that a doubling of CO2 concentrations would likely result in 2-4.5 C (3.6-8.1 F) degrees of warming. This time it restored the lower end of that range to what it was in previous reports, 1.5 C (2.7 F).
- A projected rise in global average temperatures would of 0.3 to 4.8 degrees C by the end of the century.
The IPCC assessments are important because they form the scientific basis of U.N. negotiations on a new climate deal. Much of the science used in the report comes from research we at Polar Field Services help facilitate logistically.
For more news analysis of the report, click here.