Monday, July 31, 2006


U.S. government scientists testified before a congressional committee July 20, trying to dispel any doubts that climate change and the human role in it is real, documented by abundant scientific research.

House Government Reform Committee Chairman Tom Davis, a Republican from Virginia, urged the issue be discussed in a nonpartisan way. “For too long, the political dialogue on climate change has been dominated by black-and-white grandstanding, either finger-wagging or head-in-the-sand denial and denunciation,” he said. “There has been no reasonable discourse.”

Committee members wanted to know if climate change was real and what is the impact of human activity.

The director of the National Climatic Data Center of the National Oceanic and Atmospheric Administration, Thomas Karl, said: “Some greenhouse gases are increasing in the atmosphere because of human activities and increasingly trapping more heat.”

Scientists use climate models to project what the different outcomes might result from fluctuations of the many variables in the climate system. Climate models are computer programs that use mathematical equations to simulate the interactions of the atmosphere, oceans, land surface and ice. “Climate models have become the primary means to predict climate,” said Karl.

Scientists have to use some approximations in their data about climate conditions in constructing the models. Critics of climate-change science argue those models are inaccurate and provide insufficient basis upon which to make major changes in the use of fossil fuels, which create the greenhouse gases believed to contribute to global warming.
Mr Karl stood by the models. “They’re reliable enough to be a very useful guide into the future,” he said.

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