In a speech in Washington, D.C., today, climate activist Al Gore called for the United States to move toward using electricity that comes exclusively from carbon-free sources within 10 years in order to stave off catastrophic climate change. “I ask you to join with me to call on every candidate, at every level, to accept this challenge,” he said. “It’s time for us to move beyond empty rhetoric. We need to act now.” Gore said that the convergence of high oil prices, worries about energy independence, and the threat of climate crisis have created a new political environment, paving the way for ultra-ambitious energy policies that could finally break the country’s addiction to fossil fuels. Gore’s Alliance for Climate Protection estimates that such a conversion to clean electricity would cost up to $3 trillion over 30 years, but Gore said building a new round of conventional coal plants would also cost roughly as much. Gore’s plan calls for continued reliance on nuclear power at current levels while dramatically increasing power sourced from geothermal, solar, and wind. Meanwhile, some Democrats are quietly dreading fallout from the anticipated conservative backlash to Gore’s speech, fearing that a renewed emphasis on climate issues now could turn the debate over short-term energy prices in favor of Republicans.