I never thought I’d favor nuclear power. But here it is: I believe nuclear energy is our last best chance to stem the tide of climate change. Time is running out for reversing greenhouse gas emissions and transitioning from the fossil fuel age. Nuclear power must occupy a larger share of our energy mix and replace coal-fired power plants. For energy policy, I think “near-term” decisions should still favor: (1) energy efficiency; (2) big wind; and (3) small solar. But nuclear power is going to be needed, too. (Comment)