Feb. 2, 2007 — Scientists from 113 countries issued a landmark report Friday saying they have little doubt global warming is caused by man, and predicting that hotter temperatures and rises in sea level will "continue for centuries" no matter how much humans control their pollution.
A top U.S. government scientist, Susan Solomon, said "there can be no question that the increase in greenhouse gases are dominated by human activities."
Environmental campaigners urged the United States and other industrial nations to significantly cut their emissions of greenhouse gases in response to the long-awaited report by Intergovernmental Panel on Climate Change.
"It is critical that we look at this report ... as a moment where the focus of attention will shift from whether climate change is linked to human activity, whether the science is sufficient, to what on earth are we going to do about it," said Achim Steiner, the executive director of the U.N. Environment Program.
"The public should not sit back and say 'There's nothing we can do'," Steiner said. "Anyone who would continue to risk inaction on the basis of the evidence presented here will one day in the history books be considered irresponsible."
The 21-page report represents the most authoritative science on global warming as the panel comprises hundreds of scientists and representatives. It only addresses how and why the planet is warming, not what to do about it. Another report by the panel later this year will address the most effective measures for slowing global warming.
One of the authors, Kevin Trenberth, said scientists are worried that world leaders will take the message in the wrong way and throw up their hands. Instead, world leaders should reduce emissions and adapt to a warmer world with wilder weather, he said.
"This is just not something you can stop. We're just going to have to live with it," said Trenberth, the director of climate analysis for the National Center for Atmospheric Research in Boulder, Colo. "We're creating a different planet. If you were to come up back in 100 years time, we'll have a different climate."
The scientists said global warming was "very likely" caused by human activity, a phrase that translates to a more than 90 percent certainty that it is caused by humans burning fossil fuels. That was the strongest conclusion to date, making it nearly impossible to say natural forces are to blame.
It also said no matter how much civilization slows or reduces its greenhouse gas emissions, global warming and sea level rise will continue on for centuries.
"Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level," the scientists said.
The report blamed man-made emissions of greenhouse gases for fewer cold days, hotter nights, killer heat waves, floods and heavy rains, devastating droughts, and an increase in hurricane and tropical storm strength — particularly in the Atlantic Ocean.
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.
Hays stopped short of saying whether or how the report could bring about change in President Bush's policy about greenhouse gas emissions.
