AL GORE, THE SIERRA CLUB, and environmentalists everywhere suddenly have a new best friend when it comes to fighting global warming: the nuclear industry. Helping to frame nuclear power as the solution to climate change is the industry-funded Clean and Safe Energy Coalition, headed by Greenpeace cofounder Patrick Moore and former EPA administrator Christine Todd Whitman. Nuclear power plants, they emphasize, "generate no air pollutants or greenhouse gases" and could provide for our future energy needs "without cramping lifestyles."

Alarmed by signs of a changing climate, some environmentalists are taking a fresh look at nuclear's advantages. Nukes are "base-load" plants that can operate around the clock, unlike wind and solar facilities. There haven't been any major accidents in this country since Three Mile Island in 1979 (although we came darn close in 2002 at the Davis-Besse reactor in Ohio). And nukes already provide 20 percent of the United States' electrical power and 80 percent of France's.

That fresh look, however, reveals that the now-mature nuclear industry is no closer to resolving its fundamental problems than it was 40 years ago. It has yet to find a way to safely dispose of its long-lasting, highly radioactive waste, and nuclear power remains inextricably tied to nuclear weapons proliferation. (Iran still insists, for example, that its uranium-enrichment program is for power production only.)

To affect global warming, says an influential study by the Massachusetts Institute of Technology, at least 1,000 new reactors would have to be constructed worldwide. Building those reactors would require a stupendous amount of money. Since capital is a limited resource, there would be less to spend on the many far-cheaper ways to cut down on carbon dioxide emissions: conservation, cogeneration (utilizing the heat produced by industrial processes to make electricity), and wind, to name a few. A dollar spent on energy efficiency would save seven times more carbon dioxide than a dollar spent on nuclear power.

In the end, it's not environmentalists wearing "No Nukes" buttons who have prevented any new reactor from being ordered in this country since 1978; it's Wall Street. Even with enormous subsidies from the Department of Energy and a taxpayer-funded shield from liability for major accidents through the Price-Anderson Act, no private utility has committed to building a new plant. Why? Because virtually every other form of power is cheaper and less risky. As Peter Bradford, a former member of the Nuclear Regulatory Commission, told the New York Times: "The abiding lesson that Three Mile Island taught Wall Street was that a group of NRC-licensed reactor operators, as good as any others, could turn a $2 billion asset into a $1 billion cleanup job in about 90 minutes." So the government can continue to subsidize the industry, says Amory Lovins of the Rocky Mountain Institute, but the effect "will be the same as defibrillating a corpse: It will jump, but it will not revive."

Chart: John Blanchard, source: International Energy Agency