Climate change is "unequivocal" and it is 90 percent certain that the "net effect of human activities since 1750 has been one of warming," the Intergovernmental Panel on Climate Change (IPCC) —a panel of more than 2,500 scientists and other experts—wrote in its first report on the physical science of global warming earlier this year. In its second assessment, the IPCC stated that human-induced warming is having a discernible influence on the planet, from species migration to thawing permafrost. Despite these findings, emissions of the greenhouse gases driving this process continue to rise thanks to increased burning of fossil fuels while cost-effective options for decreasing them have not been adopted, the panel found in its third report.
The IPCC's fourth and final assessment of the climate change problem—known as the Synthesis Report—combines all of these reports and adds that "warming could lead to some impacts that are abrupt or irreversible, depending upon the rate and magnitude of the climate change." Although countries continue to debate the best way to address this finding, 130 nations, including the U.S., China, Australia, Canada and even Saudi Arabia, have concurred with it.
"The governments now require, in fact, that the authors report on risks that are high and 'key' because of their potentially very high consequence," says economist Gary Yohe, a lead author on the IPCC Synthesis Report. "They have, perhaps, given the planet a chance to save itself."
Among those risks...
Scientific American
