Earth's temperatures heating up / Averages to rise 8 degrees by end of century, climate scientist says

Warren Washington, chief of the Climate Change Research Group at the National Center for Atmospheric Research in Boulder, Colo., offered his long- range forecast here at the annual meeting of the American Association for the Advancement of Science, where climatologists and physicists are discussing the various computer models they have created to explain past climate changes and the forecast for the near-term future.

In only the past 25 years, he said, global average temperatures have already risen between a third and eight-tenths of a degree, and pace is increasing even now, he said.

On the basis of the most recent computer models by many groups -- including those developed by his own colleagues at Boulder -- Washington said, "Scientific confidence in the ability of the models to project future climate has increased." Recent experiments as well as routine monitoring, he said, "have found evidence of global climate changes already occurring that are much larger than can be explained by the climate's natural variability."

"Sequestering the carbon dioxide burden would slow down the pace of climate change appreciably," Washington conceded. "But we also ought to start cutting back on emissions as a precautionary principle -- because every time you put a single carbon dioxide molecule into the atmosphere, it stays there for 900 to 1,000 years or so."

Washington is a 40-year veteran of climate research, and leads the Boulder team's development of computer climate models. He is also chairman of the National Science Board and has been an adviser on climate issues to five presidential administrations, from Jimmy Carter to President Bush.