August 26, 2004
U.S. Report Turns Focus to Greenhouse Gases
By ANDREW C. REVKIN
n a striking shift in the way the Bush administration has portrayed the science of climate change, a new report to Congress focuses on federal research indicating that emissions of carbon dioxide and other heat-trapping gases are the only likely explanation for global warming over the last three decades.
In delivering the report to Congress yesterday, an administration official, Dr. James R Mahoney, said it reflected "the best possible scientific information" on climate change. Previously, President Bush and other officials had emphasized uncertainties in understanding the causes and consequences of warming as a reason for rejecting binding restrictions on heat-trapping gases...
...That may be harder to do this time. The new report, online at www.climatescience.gov, is accompanied by a letter signed by Mr. Bush's secretaries of energy and commerce and his science adviser.
The White House declined yesterday to explain the change in emphasis, referring reporters to Dr. Mahoney, assistant secretary of commerce for oceans and atmosphere and the director of government climate research...
...In such conditions, it said, plots of shortgrass prairie in northeastern Colorado contained less of the nutrient nitrogen, and their grasses were less digestible than those that grew with no extra carbon dioxide.
"In another experiment, increased CO2 stimulated the growth of five of the most important species of invasive weeds, more than any other plant species yet studied," the report said. "This suggests that some weeds could become bigger problems as CO2 increases."