The assessment, released today (Sept. 27), is the first major report from the Intergovernmental Panel on Climate Change (IPCC) since 2007, and presents the strongest case yet for human-caused global warming since the IPCC was established in the late 1980s.

"There's much stronger evidence connecting human activity to changes in temperature, melting glaciers and ocean warming," said Gerald Meehl, a senior scientist at the National Center for Atmospheric Research and one of the authors of the new report. "There's a lot more evidence that connects human activity to changes in the climate system."

In the new summary, climate scientists say they are at least 95 percent certain that people are responsible for the warming oceans, rapidly melting ice and rising sea levels that have been observed since the 1950s. The 2007 report linked human activities to climate change with 90 percent certainty, which was a considerable leap from the 66 percent probability stated in the organization's 2001 report.