The unmistakable onset of climate change has led many to advocate a major expansion of nuclear power. At best, however, nuclear power would only provide a small contribution to cutting greenhouse gas emissions, and it carries risks that other measures to the same end do not pose — especially that of nuclear weapons proliferation. It is argued that simple prudence favors a go-slow approach until the international community can establish robust proliferation constraints, and it is evident that other carbon-free technologies (...) do not suffice to meet the climate challenge. (shrink)