U.S., China Got Climate Warnings Toned Down

Director of WWF's Global Climate Change Programme Hans Verolme talks to the media during a press conference at the Residence Palace in Brussels, Thursday April 5, 2007. (Thierry Charlier - AP)

NCAR scientist Kathleen Miller -- a lead author of the chapter on fresh water resources -- said she is confident that dry regions such as the American Southwest will experience more drought in future decades, but it is hard to predict how severe the changes will be.

"The extent of the damage will depend on how much warming we experience, and how rapidly it proceeds," Miller said.

The report also examines how infectious diseases might spread in a warmer climate. Jonathan Patz, an associate professor of environmental studies and population health sciences at the University of Wisconsin at Madison and a lead author of the North America chapter, said the currently projected warming alone will probably mean that by 2050, the Northeast will experience 68 percent more "red ozone alert" days indicating the air is unhealthy to breathe.

The U.S. strain of the West Nile virus is also especially responsive to warmer temperatures, Patz added, and Africa is expected to experience an uptick in malaria, a disease that already accounts for 1 million to 2 million deaths a year worldwide.

"Climate change presents one of the most challenging environmental and public health threats of this millennium," Patz said.

Bush's top environmental adviser, James L. Connaughton, told reporters in the conference call that the report "reinforces" the administration's belief that it is pursuing the right policies to combat climate change. This includes a push for increased auto efficiency and greater use of renewable fuels.

But Rep. Edward J. Markey (D-Mass.), who chairs a select House committee on climate change, said the administration is dealing only with a fraction of greenhouse gas emissions by regulating cars, and Congress is committed to passing a mandatory, economy-wide limit on emissions by the end of the year.

"The conclusions in the report are so scary that whatever success the Bush administration may have had in watering down the language won't have any impact on what the reaction of the world will be," Markey said in an interview, adding that Bush will soon have to decide whether to veto an emissions cap.

"Congress is heading toward a legislative showdown with the president on this issue. On that, there's no doubt."