WASHINGTON (AP) - The Obama administration is more certain than ever that global warming is changing Americans' daily lives and will worsen - conclusions that scientists will detail in a massive federal report to be released Tuesday.
Once people thought global warming was more in the future and more of an issue in other parts of the world, but the National Climate Assessment will emphasize how the United States is already paying the multibillion-dollar price for man-made climate change, said study co-author Donald Wuebbles, a climate scientist at the University of Illinois.
"We're already seeing extreme weather and it's happening now," Wuebbles said Monday. "We're seeing more heat waves, particularly in the West and in the South."
This final report is a rewritten and shortened version of a draft that was released in January 2013, with more scientific references, reviews by experts and the public, and a thorough review by the National Academy of Sciences, said Wuebbles and report lead author Gary Yohe of Wesleyan University in Connecticut. There is even stronger evidence than in 2013, Yohe said.
The draft came out just as meteorologists calculated that 2012 was the hottest year on record for the United States, but last year was slightly cooler than the 20th century average. And in the time since the draft report was released, the United States has seen lots of extremes.
Nineteen different state records were set for individual months, such as the hottest January in California this year.
And since the draft was released, there's been a dramatic new extreme that a good part of the country is worrying about: The drought in California, where a few rural places are in danger of running out of water.
In January 2013, none of California was in either extreme or exceptional drought; now nearly 77 percent of the state is. It is too early to point directly at the near-record California drought as another sign of global warming, but it fits the pattern, Yohe and Wuebbles said.
The Obama administration will likely use the 840-page report as scientific justification to reduce emissions of heat-trapping gas from the burning of fossil fuels, such as coal, gas and oil and to encourage local communities to adapt to changes in the climate. White House counselor John Podesta called it "the most authoritative and comprehensive source of scientific information" on how climate change will hit all parts of the nation and the economy.
"Hundreds of the best climate scientists from across the U.S., not just in the public sector but in the private sector as well, have worked over the last four years to produce this report," Podesta said in a Monday briefing at the White House. "This assessment is about presenting actionable science."
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