Draft IPCC Report Leaves Little Doubt Humans Are Causing Global Warming

By: Terrell Johnson

Published: August 19,2013

 

 

 

 

Waves break along the coast of Sunset Beach, Calif. A leaked draft of the upcoming Fifth Assessment report by Intergovernmental Panel on Climate Change says global sea levels could rise by more than 3 feet by the end of the century. (David McNew/Getty Images)

An international team of climate scientists says it is 95 to 100 percent confident that human activity -- largely from burning fossil fuels -- is the main cause of global warming since the 1950s, according to a leaked draft of the upcoming report from the Intergovernmental Panel on Climate Change.
The report, the first by the IPCC in six years and set to be released in September, also says that global sea levels could rise more than 3 feet by the end of this century if no action is taken to curb the worldwide emissions of greenhouse gases before then.
The panel found it "extremely likely" that humans were responsible for "more than half of the observed increase in global average surface temperature from 1951 to 2010," the draft report says, according to the New York Times.
"There is high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level, and changed some climate extremes in the second half of the 20th century."
Reuters was the first to publish highlights from the report Friday, emphasizing that while climate scientists are more certain than ever about the causes of global warming, they remain less sure about how climate change will impact societies at a regional and local level.
"We have a got quite a bit more certain that climate change ... is largely manmade," Reto Knutti, a professor at the Swiss Federal Institute of Technology, told Reuters. "We're less certain than many would hope about the local impacts."
A look at the IPCC's past reports shows the group's increasing confidence about the causes of climate change. Its 2001 assessment said it was "likely" -- a 66 percent probability -- that humans were causing warming, while the 2007 report raised that number to 90 percent, or "very likely." (See an explanation of the IPCC probability numbers here.)
The panel also said the evidence is now "unequivocal" for the phenomenon of global sea level rise, which it expects to increase by about 1 to 3 feet by 2100, depending on actions taken to reduce greenhouse gas emissions between now and the end of the century.
That's nearly double the estimates from the 2007 report, which did not take into account melting from the ice sheets in Greenland and Antarctica.
Jonathan Lynn, the IPCC's head of communications, told Mother Jones that the leaks are no surprise to the organization, because they must be reviewed by many people before they're published in their final form.
"There's no question that the final report will not be the same as the drafts," he said, noting that the group has fielded some 1,800 comments from governments that will have to be incorporated into the final report, to be published after a closed-door negotiating meeting by climate scientists and government leaders from around the world in September.