Global Warming to Continue for Centuries

Global warming is so severe that it will "continue for centuries," leading to a far different planet in 100 years, warned a grim landmark report from the world's leading climate scientists and government officials. Yet, many of the experts are hopeful that nations will now take action to avoid the worst scenarios.

They tried to warn of dire risks without scaring people so much they'd do nothing _ inaction that would lead to the worst possible scenarios.

"It's not too late," said Australian scientist Nathaniel Bindoff, a co-author of the authoritative Intergovernmental

Panel on Climate Change report issued Friday. The worst can be prevented by acting quickly to curb greenhouse gas emissions, he said.

The worst could mean more than 1 million dead and hundreds of billions of dollars in costs by 2100, said Kevin Trenberth of the National Center for Atmospheric Research in Colorado, one of many study co-authors. He said that adapting will mean living with more extreme weather such as severe droughts, more hurricanes and wildfires.

"It's later than we think," said panel co-chair Susan Solomon, the U.S. National Oceanic and Atmospheric Administration scientist who helped push through the document's strong language.

Solomon, who remains optimistic about the future, said it's close to too late to alter the future for her children _ but maybe it's not too late for her grandchildren.

The report was the first of four to be released this year by the panel, which was created by the United Nations in 1988. It found:

_Global warming is "very likely" caused by man, meaning more than 90 percent certain. That's the strongest expression of certainty to date from the panel.

_If nothing is done to change current emissions patterns of greenhouse gases, global temperature could increase as much as 11 degrees Fahrenheit by 2100.

_But if the world does get greenhouse gas emissions under control _ something scientists say they hope can be done _ the best estimate is about 3 degrees Fahrenheit.

_Sea levels are projected to rise 7 to 23 inches by the end of the century. Add another 4 to 8 inches if recent, surprising melting of polar ice sheets continues.

Sea level rise could get worse after that. By 2100, if nothing is done to curb emissions, the melting of Greenland's ice sheet would be inevitable and the world's seas would eventually rise by more than 20 feet, Bindoff said.

That amount of sea rise would take centuries, said Andrew Weaver of the University of Victoria in Canada, but "if you're in Florida or Louisiana, or much of western Europe or southeast Asia or Bangladesh ... or Manhattan ... you don't want that," he said.

The report spurred bleak reactions from world leaders.