US faces serious threats from climate change: study

The US is already being struck by the effects of climate change and the threats will only grow if the world does not speed up its efforts to reduce pollutants blamed for rising temperatures, the US government warned Tuesday.

In a much-anticipated report that was compiled over years by US agencies and independent scientists, the government painted a broad picture of the threats that the United States faces from climate change.

It warned that all regions of the country will be affected: Coastal regions could be devastated by rising sea levels and stronger storm surges; species in the water and on land could be killed off; more heat waves and longer droughts could spark more flooding, wildfires and diseases.

"The bottom line is this: Climate change already is affecting the things that we value," said John Holdren, director of White House Office of Science and Technology Policy. "How severe these impacts will be is largely in our hands."

But the report did not offer a timeframe to avoid the worst effects and made no specific policy prescriptions. The US Congress is in the middle of debating a climate bill that would aim to cut US emissions about 17 percent below 2005 levels by 2020 and 80 percent by 2050.

World governments are also hoping to get agreement on a new climate treaty by a critical December summit in Copenhagen.