But if a curious high school athlete is tempted by the title "Science as a Contact Sport," he may find himself blocked by a line of climatological reasoning and terms such as "ecology" and "anthropogenic," rarely heard on the football field.

Using plainer language, Schneider raises a broader problem than climate change.

"Can democracy survive complexity?" he asks.

It seems clear to him that scientific judgments, reached as a consensus of career-long study, should overwhelm national rivalries and partisan politics when governments have great decisions to make. He questions the news principle of balance: that is, a controversial statement should be followed by a statement from the other side.

"If the public understood the basics of the real risks to nature, and to themselves, their posterity and their world, they would be much more likely to send strong signals to their representatives to act in a precautionary way," he writes.

For decades, governments and scientists have been citing dangers of global warming as facts and huge problems. But not everybody agrees. Some doubting scientists and businesses that would be hit by the cost of eliminating pollutants have helped stall international accord on countermeasures. So has failure of the U.S. and Chinese governments to compromise on what should be done to limit emissions of carbon dioxide.

The view of Sen. James Inhofe, former chairman of the Senate Environment and Public Works Committee, is among the most hostile. Schneider says the senator accused him of fathering "the greatest environmental hoax."

Schneider emphasizes that scientists take extreme pains to estimate the probability and effects of climate change, rather than just saying dangers are possible. He's a professor of biological sciences and has advised seven presidents, from both parties. The Intergovernmental Panel on Climate Change, squads of scientists like him who advise governments, spend much of their time translating words such as "likely" or "very likely" into percentages of probability.

That work resembles calculating odds on a football game, only the calculation on this game _ the possible worldwide disasters of climate change _ has been going on for over 30 years.