It had compared the sharp curve of the hockey blade to the recent uptick in temperatures ¡ª a 1 degree rise in global average surface temperatures in the Northern Hemisphere during the 20th century ¡ª and the stick's long shaft to centuries of previous climate stability.

That research is "likely" true and is supported by more recent data, said John "Mike" Wallace, an atmospheric sciences professor at the University of Washington and a panel member.

Rep. Sherwood Boehlert, chairman of the House Science Committee, had asked the academy for the report last year after the House Energy and Commerce Committee chairman, Rep. Joe Barton aunched an investigation of the three climate scientists.

The Bush administration has maintained that the threat from global warming is not severe enough to warrant new pollution controls that the White House says would have cost 5 million Americans their jobs.

"This report shows the value of Congress handling scientific disputes by asking scientists to give us guidance," Boehlert said Thursday. "There is nothing in this report that should raise any doubts about the broad scientific consensus on global climate change."

The academy panel said it had less confidence in the evidence of temperatures before 1600.

But it considered the evidence reliable enough to conclude there were sharp spikes in carbon dioxide and methane, the two major "greenhouse" gases blamed for trapping heat in the atmosphere, beginning in the 20th century, after remaining fairly level for 12,000 years.

Between 1 A.D. and 1850, volcanic eruptions and solar fluctuations had the biggest effects on climate. But those temperature changes "were much less pronounced than the warming due to greenhouse gas" levels by pollution since the mid-19th century, the panel said.

The National Academy of Sciences is a private organization chartered by Congress to advise the government of scientific matters.