Greenhouse Effects

Carbon dioxide and other gases from the burning of fossil fuels collect in the atmosphere and act like the glass walls of a greenhouse, trapping heat on the earth's surface. Scientists predict that the planet's average temperature could rise as much as 6.3[degrees]F (3.5[degrees]C) over the next century, and we are already seeing heat waves, melting polar ice and rising seas. Local impact remains unpredictable: some areas could suffer stronger storms and other places severe drought. Seven environmental groups--Environmental Defense Fund, Natural Resources Defense Council, Sierra Club, Union of Concerned Scientists, U.S. Public Interest Research Group, World Resources Institute and World Wildlife Fund--have put together a world map showing "early-warning signs" of global warming. Reviewed by a team of scientists, the signs fall into two categories: direct manifestations of warming, called fingerprints, and events that could become more frequent and widespread with climate change, which are labeled harbingers. Here's an exclusive advance look at the highlights of the map. A more detailed version will be posted on Dec. 15 at www.climatehotmap.org