Climate Change Affects Security

Climate change could be one of the greatest national security challenges ever faced by U.S. policy makers, according to a new joint study by two U.S. think tanks.

The report, to be released Monday, raises the threat of dramatic population migrations, wars over water and resources, and a realignment of power among nations.

During the last two decades, climate scientists have underestimated how quickly the Earth is changing — perhaps to avoid being branded as "alarmists," the study said. But policy planners should count on climate-induced instability in critical parts of the world within 30 years.

The report was compiled by a panel of security and climate specialists, sponsored by the Center for Strategic and International Studies and the Center for a New American Security. The Associated Press received an advance copy.

Climate change is likely to breed new conflicts, but it already is magnifying existing problems, from the desertification of Darfur and competition for water in the Middle East to the disruptive monsoons in Asia which increase the pressure for land, the report said.

It examined three scenarios, ranging from the consequences of an expected temperature increase of 2.5 degrees Fahrenheit by 2040, to the catastrophic implications of a 10-degree rise by the end of the century.