Bradford Plumer
November 20, 2009

For years, advocates of climate-change legislation have struggled to find a sales pitch that will sway even the most hardened of skeptics. Polar bears, green jobs, urgent pleas to think of the grandkids … none of them have quite done the trick. But recently, a new argument has come to the fore: the national security case for cutting carbon emissions. At a hearing in October, Senate Democrats invited military leaders and strategists to speak about both the dangers of America’s oil dependency and the potential for rising temperatures to create new security threats around the globe. Dennis McGinn, a retired Navy vice admiral, conjured up a not-too-distant future in which increased drought, flooding, and crop failures ravaged areas like sub-Saharan Africa or Bangladesh, fueling violent conflict. Meanwhile, he said, the U.S. military could find itself handcuffed by its over-reliance on oil if prices start spiking. “Continuing the United States’ pattern of energy usage in a business-as-usual manner,â€