"Changes in climate are now affecting physical and biological systems on every continent," says a draft obtained by The Associated Press of a report on warming’s impacts by the panel, the authoritative U.N. network of 2,000 scientists and more than 100 governments.

In February, the panel declared it "very likely" most global warming has been caused by manmade emissions of carbon dioxide and other greenhouse gases.

Animal and plant life in the Arctic and Antarctic is undergoing substantial change, scientists say. Rising sea levels elsewhere are damaging coastal wetlands. Warmer waters are bleaching and killing coral reefs, pushing marine species toward the poles, reducing fish populations in African lakes, research finds.

"Hundreds of species have already changed their ranges, and ecosystems are being disrupted," said University of Michigan ecologist Rosina Bierbaum, former head of the U.S. IPCC delegation. "It is clear that a number of species are going to be lost."

The IPCC draft estimates that if temperatures rise approximately 2 to 4 degrees Fahrenheit more, one-third of species will be lost from their current range, either moved elsewhere or made extinct.