Global warming and the spread of nuclear weapons are the two great moral and technological challenges of our times. Both are caused by machines made by humans. Both could destroy life on the planet. Both can be prevented. But in our zeal to find a solution to one, we must not make the other threat worse.

Some tout civilian nuclear power as the clean energy source of the future. It does not generate carbon gases and could replace dirty coal-powered plants. But there is a catch. The same facilities that make and reprocess the fuel for nuclear reactors could make fuel for nuclear bombs. For example, more than $100 billion has been spent globally on projects to commercialize plutonium, yielding 250 metric tons scattered in repositories throughout the world, enough to make more than 30,000 nuclear bombs.

Conversely, failure to stem nuclear proliferation complicates potential solutions to the climate crisis. As former CIA Director John Deutch and colleagues observe, "the prospects for nuclear energy to play a larger role in our energy future would be devastated by any nuclear-weapons incident associated with the nuclear-power fuel cycle anywhere in the world." Security analyst Daniel Poneman calls this scenario a "proliferation Chernobyl," which "could mean the end of nuclear energy for decades."

Given these dicey tradeoffs, it is imperative that policy makers see these twin threats as intimately entwined. The solutions to one must propel policies that promote solutions to the other.

Enter the Bush administration's Global Nuclear Energy Partnership, an effort to expand the use of nuclear power globally. It promises to meet escalating energy demand while controlling the nuclear-fuel cycle. Through international cooperation the partnership aims to produce "abundant energy without generating ... greenhouse gases." Further, by accelerating research on advanced reactors with potential to use nuclear waste as fuel, the program claims to "minimize waste and reduce proliferation concerns." Last month in Vienna, U.S. Secretary of Energy Samuel Bodman announced that 11 new nations had joined original partners China, France, Japan, Russia and the United States in this "new global nuclear-power partnership."

Could this 21st century version of President Eisenhower¹s "Atoms for Peace" be the silver bullet we need to slay the twin Gorgons of global warming and nuclear proliferation? Unfortunately, the nuclear partnership is more likely to increase risks of a "proliferation Chernobyl," since its technical centerpiece is construction of the world's largest nuclear reprocessing facility, capable of "recycling" 2,000 to 3,000 tons of spent nuclear fuel.

Since 1982, the U.S. has steered clear of the nuclear reprocessing business, and for good reason. "Fast breeder" reactors that burn spent nuclear fuel and produce plutonium have proved to be economic liabilities in Britain and Russia while producing mountains of bomb material. Even pro-nuclear-power experts agree that wide-scale generation of plutonium presents significant proliferation dangers. Among these skeptics is John Deutch, who said earlier this year that Global Nuclear Energy Partnership "is hugely expensive, hugely misdirected and hugely out of sync with the needs of the industry and the nation."

Today there is broad agreement that a comprehensive nonproliferation solution must include reform in how fuel is produced for nuclear reactors. Proposals advanced by Director-General Mohamed ElBaradei of the International Atomic Energy Agency and others seek to end the further production of materials for use in nuclear weapons and to stop -- at least temporarily -- construction of new facilities for enriching uranium or separating plutonium. The nuclear partnershp rushes headlong in the opposite direction.

Secretary Bodman is expected to decide early next year whether to move ahead with development of the first nuclear fuel reprocessing facility on American soil in over 35 years. As the decision nears, it behooves citizens to take a closer look at the proposed nuclear partnership, pitched as the solution for global warming and nuclear proliferation. Using breeder reprocessing nuclear-power generation might help us reduce greenhouses gases, but at the expense of spreading more weapons-grade plutonium around the world.

Is it possible to fashion a nuclear-power solution to the climate crisis without worsening the proliferation problem? The nuclear industry is hard at work on "proliferation-resistant" reactor designs, but even these pose security risks that would be magnified in a world where nuclear power is counted upon to produce enough electricity to significantly reduce fossil-fuel emissions.