Global Warming

IPCC Report: Strongest Case Yet for Human-Caused Global Warming

The Intergovernmental Panel on Climate Change's latest report on the science of global warming points at humans as being primarily to blame for climate change, saying it is "extremely likely" that human activities have caused most of the warming of the planet's surface since the 1950s.

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.

In the new summary, climate scientists agree, with at least 95 percent certainty, that humans are responsible for most of the observed effects of climate change since the 1950s, including warming oceans, rapidly melting ice and rising sea levels. In 2007, the IPCC report linked human activities to climate change with 90 percent certainty, which was a considerable leap up from the 66 percent probability stated in the organization's report from 2001.

The new report also contains updated projections for various climate scenarios, including sea level rise, melting glaciers and rising global average temperatures.

Today's assessment is part of the IPCC's latest summary on climate change, called the Fifth Assessment Report of AR5. The IPCC reports consist of four sections: the Working Group I report on the science of climate change; the Working Group II report on the vulnerabilities and socioeconomic impacts; the Working Group III report on possible ways to mitigate climate change; and the Synthesis Report, which reviews the findings from all the working groups and integrates relevant information for policymakers. The other sections of the IPCC's Fifth Assessment Report will be released in 2014.

The IPCC was established by the United Nations in 1988 to comb through the most recent published and peer-reviewed research on global warming, and put together comprehensive reports on the risks and impacts of climate change.

The assessments undergo an extensive review process that involves thousands of scientists and government officials, and the final products represent consensus within the scientific community. As a result, the IPCC reports are considered the authority on the risks and impacts of global warming.

Smog obscures the Los Angeles skyline: