Last summer, in the midst of a searing heat wave that gripped the nation's capital, the Science, Space, and Technology Committee, upon which I sit, was trying to get a grip on the threat posed by a much larger kind of heat wave, global warming. The testifying scientists asked us to imagine 90-100 degree summer days running nearly three months, triple the current number of days that are this warm. Air quality would deteriorate as the heat wave progressed, since the higher temperatures would cook up a chemical soup of irritating pollutants.

Global warming, commonly referred to as the "greenhouse effect," results from the increasing concentration of some gases and particles in the atmosphere allowing sunlight tofilter through to the surface of the planet, but preventing the sunlight's radiant infrared energy from escaping back into space. Carbon dioxide releases from the burning of fossil fuels and tropical forests currently account for half of annual greenhouse gas emissions. Other major infrared-trapping gases include methane, chlorofluorocarbons, and nitrous oxide. The greater the concentration of these gases, the less infrared energy that can escape. The resulting climate changes may be extremely significant.