Warming 'Likely' Man-Made, Unstoppable

The world's leading climate scientists said global warming has begun, is "very likely" caused by man, and will be unstoppable for centuries, according to a report obtained Friday by The Associated Press.

The scientists _ using their strongest language yet on the issue _ said now that the world has begun to warm, hotter temperatures and rises in sea level "would continue for centuries," no matter how much humans control their pollution. The report also linked the warming to the recent increase in stronger hurricanes.

"The observed widespread warming of the atmosphere

and ocean, together with ice-mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that is not due to known natural causes alone," said the report by the Intergovernmental Panel on Climate Change _ a group of hundreds of scientists and representatives of 113 governments.

The phrase "very likely" translates to a more than 90 percent certainty that global warming is caused by man's burning of fossil fuels. That was the strongest conclusion to date, making it nearly impossible to say natural forces are to blame.

What that means in simple language is "we have this nailed," said top U.S. climate scientist Jerry Mahlman, who originated the percentage system.

Sharon Hays, associate director of the Office of Science and Technology Policy at the White House, welcomed the strong language of the report.

"It's a significant report. It will be valuable to policy makers," she told The Associated Press in an interview in Paris, where hundreds of scientists and government officials were meeting to discuss global warming.

Hays stopped short of saying whether or how the report could bring about change in President Bush's policy about greenhouse gas emissions.

The 20-page summary of the panel's findings, due to be officially released later in the day, represents the most authoritative science on global warming.

The new language marked an escalation from the panel's last report in 2001, which said warming was "likely" caused by human activity. There had been speculation that the participants might try to say it is "virtually certain" man causes global warming, which translates to 99 percent certainty.

The panel predicted temperature rises of 2-11.5 degrees Fahrenheit by the year 2100. That was a wider range than in the 2001 report.

However, the panel also said its best estimate was for temperature rises of 3.2-7.1 degrees Fahrenheit. In 2001, all the panel gave was a range of 2.5-10.4 degrees Fahrenheit.

On sea levels, the report projects rises of 7-23 inches by the end of the century. An additional 3.9-7.8 inches are possible if recent, surprising melting of polar ice sheets continues.