Policymakers must confront the dilemma that fossil fuels continue to be an indispensable source of energy even though burning them produces atmospheric accumulations of carbon dioxide that increase the likelihood of potentially disastrous global climate change. Currently, technology that would capture carbon dioxide emitted by power plants and sequester it harmlessly underground or undersea instead of releasing it into the atmosphere might double the cost of generating electricity. But because sequestration does not affect the cost of electricity transmission and distribution, delivered prices will rise less, by no more than 50 percent. Research into better technologies for capturing carbon dioxide will undoubtedly lead to lowered costs.