By Sid Perkins
Global warming predicted for the coming decades may decrease heating bills in some parts of the United States. Ironically, the extra electricity needed for air conditioning could result in increased emissions of planet-warming carbon dioxide.
The atmospheric concentration of carbon dioxide, which traps heat at Earth’s surface, has been on the rise for more than 150 years, largely because of the burning of fossil fuels. Some computer simulations suggest that by the end of this century, the global average temperature could be as much as 3.4°C higher than it is now, says David J. Erickson III, a climate modeler at the Oak Ridge (Tenn.) National Laboratory.