Climate change is altering the field of national security, presenting threats that cannot be met by traditional structures of state military defense, according to a new report by the policy group American Security Project.

As the climate warms, it is likely to place stress on food and energy production, water supplies, and public health, according to the report. For a national security policy long focused on the external threats of state and nonstate actors, these nontraditional threats will require nontraditional responses, it says.

"Environmental threats blur traditional notions of national security: Secure states do not automatically mean secure people, and climate change is proving that," it adds.

The report highlights the example of Russia, where in 2010 wildfires running through forests and subterranean peat bogs left more than 55,000 people dead. The wildfires, following on the heels of a severe and unseasonal heat wave, compelled the Kremlin to abruptly reverse its dismissive position on greenhouse gas emissions.

The United States underwent its own devastating heat wave this summer, stoking one of the worst wildfire seasons on record and devastating crops across the nation's farm belt. As population growth and limited natural resources put pressure on the world's food and water supply, the consequences of such events will almost certainly grow with time, the report says.

Threats to national security are not limited to effects within America's borders, however. Just as the effects of a drought in America's heartland may be felt in food prices around the world, coping with climate change requires a broader response than state security apparatuses can provide, the report says.

"Traditional national security is giving way to international security. ... Traditional, conventional thinking will increase our vulnerability," said ex-Sen. Gary Hart (D-Colo.), as cited in the report. "Anticipation, imagination, flexibility and experimentation are needed to make us secure in an age of profound revolutionary change."

As the report notes, changes to the Earth's climate have already caused conflict and geopolitical power shifts. Many scholars attribute the Mongols' departure from the Eurasian steppes to changes in the region's temperatures. That exodus led to some of the most extensive and destructive conquests of the last millennium.

Even as climate-related legislation has stalled in the federal government, the U.S. military has shown strong signs of accepting the scientific consensus on man-made global warming.

The Quadrennial Defense Review, the legislatively mandated review of Defense Department strategy and priorities, has listed climate change as one of the nation's top national security threats. The Army Corps of Engineers, meanwhile, has projected sea level rise consistent with mainstream climate forecasts.