Sudden ChillEven a limited nuclear exchange could trigger a climate catastrophe Sid Perkins In the mid-1980s, at the height of the Cold War, the United States and the Soviet Union each had thousands of nuclear warheads, along with a multitude of aircrews and missiles, sitting on red alert to carry those bombs to their targets at a moment's notice. The philosophy of mutual assured destruction—the notion that any use of nuclear weapons would trigger a full-fledged exchange that neither nation would survive—may have deterred any use of such bombs since World War II. Today's combination of nuclear proliferation, political instability,...