In 1947, the Pentagon became interested in polar warming and global climate change. It did so not because of concerns about the natural environment, as these became generally understood by the 1980s and 1990s, but because of pragmatic defense issues : the prospect of climate change in high latitudes left military authorities worried about the United States’ ability to confront the Soviet Union in the high Arctic, where a hot conflict with its emerging cold war adversary seemed increasingly possible. Pentagon officials also saw polar warming as a broader kind of threat : a warming Arctic climate meant that the Soviet Union might obtain new advantages. By the late 1940s the polar region had become, as never before, a potential theater of war. State concern with the Arctic environment helped to shape U. S. Army, Navy, and Air Force scientific planning and tactical studies through the 1950s. Military fascination with the Arctic created new research institutions and new funding to address broad interdisciplinary problems. It helped shape a distinct form of the environmental sciences in the United States before the environmental movement (which emphasized the biological environmental sciences including ecology, genetics, and natural history) gained ground in the 1960s and early 1970s.