Famines. Diseases. Natural catastrophes. In 1945, scientists imagined these as the future faces of war. The United States and its allies prepared for a global struggle against the Soviet Union by using science to extend "total war" ideas to the natural environment. Biological and radiological weapons, crop destruction, massive fires, artificial earthquakes and tsunamis, ocean current manipulation, sea level tinkering, weather control, and even climate change-all these became avenues of research at the height of the Cold War. By the 1960s, a new phrase had emerged: environmental warfare. The same science--in fact, many of the same people--also led the way in understanding the earth's vulnerability during the environmental crisis of the 1970s. The first reports on human-induced climate change came from scientists who had advised NATO about how to protect the western allies from Soviet attack. Leading ecologists at Oxford also had helped Britain wage a war against crops in Malaya-and the Americans followed suit in Vietnam. The first predictions of environmental doomsday in the early 1970s came from the intellectual pioneers of global conflict resolution, and some had designed America's missile defense systems. President Nixon's advisors on environmental quality had learned how to think globally by imagining Mother Nature as an armed combatant. Knowledge of environmental threats followed from military preparations throughout the Cold War, from nuclear winter to the AIDS epidemic. How much of our catastrophic thinking about today's environmental crises do we owe to the plans for World War Three?