"The level of environmental insanity among US policymakers reaches new heights with this proposal," charged Mike Adams, a consumer health advocate and coauthor of "The Real Safety Guide to Protecting Your Environment ."
"Blocking the sun would devastate global ecosystems, reduce solar power efficiency, harm crops and disrupt the global food supply. It's an idea so insane it could have only come from politicians, not genuine scientists."
The suggestion came in the government's official response to a draft report by the United Nations Intergovernmental Panel on Climate Change (IPCC). The IPCC report, written by climate experts from around the world, will form the foundation for the next round of international climate negotiations. The draft was submitted to world governments for comment in 2006.
According to the U.S. response, "modifying solar radiance ... is a very important possibility that should be considered." Possible techniques for blocking out sunlight include firing giant mirrors into space, pumping reflective sulfate droplets or dust into the high atmosphere, or thousands of small, reflective balloons.
The IPCC draft report, commenting on such ideas, called them "speculative, uncosted and with potential unknown side effects."
Other portions of the report contested by the U.S. included the draft's focus on a binding international treaty to reduce emissions, and that "the report tends to overstate or focus on the negative effects of climate change."
By contrast, the U.S. wants an emphasis on voluntary emissions standards and more responsibilities for poorer countries.
The draft report predicts an average global temperature rise of between 1 and 6.3 degrees from 1990 to 2100. Professor Stephen Schneider, a key figure on the IPCC with more than 30 years of climate consultation experience, estimated that the average increase is likely to be 3 degrees or more, with a 10 percent chance of a 6 degree increase or more. He expressed alarm at how slowly the world has been responding to the threat of global warming.
"Hell, we buy fire insurance based on a 1 percent chance," he said. "If we're going to be risk averse ... we cannot dismiss the possibility of potentially catastrophic outliers and that includes [ice sheets breaking up], massive species extinctions, intensified hurricanes and all those things. There's at least a 10 percent chance of that. And that, to me, for a society is too high a risk."