Droughts, floods and wildfires have worsened due to global warming, an Obama administration report found Tuesday in the most complete federal look yet at the effects of a changing climate.
" Global Climate Change Impacts in the United States," released by White House science adviser John Holdren and National Oceanic and Atmospheric Administration head Jane Lubchenco, echoes past climate assessments, but comes amid a push in Congress and by the Obama administration to limit the emission of heat-trapping "greenhouse" gases.
"Human-induced climate change is a reality," said Lubchenco at a White House briefing. "It's not just a problem for the future."
"Climate change is happening now," says Thomas Karl, an NOAA scientist and co-editor of the report. "Changes have already been observed in all aspects of the climate." The report was commissioned during the Bush administration to combine findings from federal agencies with those from other sources. Findings include:
•U.S. temperatures have increased by almost 2 degrees over the past 50 years, and are expected to increase by as much as 4 to 11 degrees by 2100.
•Heavy downpours, rising sea levels, rapidly retreating glaciers, thawing permafrost, longer growing seasons and earlier snowmelts are expected to increase.
•Public health effects include increased heat stress, waterborne diseases, poor air quality, extreme weather events, and diseases transmitted by insects and rodents.
"I think the report's findings underline the urgency of dealing with global warming now. The impacts are already being felt, and will only get worse," says David Doniger of the Natural Resources Defense Council in Washington, D.C. "The costs are just increasing the longer we wait to take steps to address climate. The damage gets worse and the costs to make changes just get higher."
However, some disagree. "That the federal bureaucracy in Washington has produced yet another alarmist report on global warming is nothing new," Sen. James Inhofe, R-Okla., said in an e-mail. "Despite millions of dollars spent on alarmist advertising, the American public remains rightly skeptical of the so-called 'consensus' on global warming."
Says Lubchenco, "We have greater confidence now than ever before. This report is a game-changer."