“The possibility of a world transformed by climate change is not a science fiction image of a post-apocalyptic society; it is not a road warrior movie. It is happening now. There is another holocaust now in Darfur.” Brad Miller (D-NC), chairman of the Investigations and Oversight Subcommittee of the House Committee on Science and Technology, chose strong words to open the subcommittee’s September 26, 2007, hearing “The National Security Implications of Climate Change.”

The first witness was General Gordon R. Sullivan (USA Ret.), chairman of the CNA Corporation’s Military Advisory Board, which wrote the groundbreaking report National Security and the Threat of Climate Change. Sullivan reminded the congressmen of the potential destabilizing impacts of climate change—reduced access to freshwater, impaired food production, the spread of diseases, land loss due to flooding, and population displacement, among others—and their potential security consequences, which include an elevated risk of state failure, the growth of terrorism, mass migrations leading to regional and global tensions, and conflicts over resources.

China’s geopolitical importance should make it of particular concern to policymakers, said Alexander Lennon, a research fellow at the Center for Strategic and International Studies. According to Lennon, two-thirds of China’s cities are currently experiencing water and food shortages. These environmental issues already cause unrest among the population, and the combined effects of climate change and rapid urbanization could increase tensions. A destabilized China, however, is only one of the various climate-related problems the United States could face in the future. Climate change could also foster terrorism, Lennon said. Rampant poverty, growing economic inequality, state failure, and ethnic tensions form a fertile substrate for terrorist groups.

James Woolsey, vice president of Booz Allen Hamilton and former director of the CIA, argued that the threats posed by climate change and terrorism should not be isolated from one another. Indeed, “terrorists may exploit vulnerabilities in our energy production and distribution or other weaknesses in our infrastructure,” he said. Fuel convoys in Iraq, for instance, are a primary target for insurgents. Woolsey encouraged policymakers to opt for a plan that would reduce both threats simultaneously. His solution: improving U.S. energy efficiency.

As the nation’s largest single consumer of oil (1.8 percent of the U.S. total), the Department of Defense (DoD) is already working on improving energy efficiency, said Kent Butts, director of National Security Issues at the U.S. Army War College’s Center for Strategic Leadership. More generally, he continued, DoD is devoting considerable attention to the destabilizing impacts of climate change, although there is no overarching directive that guides these efforts. The Navy, for instance, is currently analyzing the security implications of shrinking ice sheets in the Arctic.

U.S. Representative Dana Rohrabacher (R-CA) shared his concerns regarding the military’s efforts to increase vehicles’ efficiency. Focusing too much on climate change, he argued, could be harmful to U.S. troops’ security. “If we decide to produce lighter vehicles in order to consume less oil, soldiers will be less protected. Aren’t our troops more important than climate change?” he asked. Sullivan responded that if lighter vehicles were produced, they would be designed so they protected soldiers as well as today’s heavier vehicles do.

Andrew Price-Smith, a professor of political science at Colorado College, emphasized another potential area of impact: global health. He explained that an increase in temperatures and precipitation could favor the proliferation and geographical expansion of infectious diseases such as cholera and malaria. The spread of deadly diseases to new areas could in turn undermine the economy (through absenteeism, increased medical costs, and premature deaths) and foster political instability.

Finally, several representatives shared their skepticism concerning climate change. Reps. Dana Rohrabacher and James Sensenbrenner (R-WI), who said they did not believe human activities have contributed to climate change, argued that the United States should not try to mitigate climate change, but instead try to adapt to it. “Fostering a more robust economy is our strongest defense against climate change,” said Sensenbrenner. “Because it is too late to prevent rising temperatures, the best response is to ensure that our economy is strong enough to adequately respond.” In other words, he was suggesting that we should not try to reduce carbon emissions, because doing so would slow economic growth. He concluded on an optimistic note: “Everyone agrees that the wealthiest countries and individuals will be the least affected by global warming. Putting more people in a position to afford air conditioning will actually save lives.” Needless to say, not everyone in the room shared his view.