Fortune magazine recently ran a story describing a study conducted by Peter Schwartz and Doug Randall for the Department of Defense.

Here is the public report of that study. (22 pages)

The purpose of this report is to imagine the unthinkable -- to push the boundaries of current research on climate change so we may better understand the potential implications on United States national security.

We have interviewed leading climate change scientists, conducted additional research, and reviewed several iterations of the scenario with these experts. The scientists support this project, but caution that the scenario depicted is extreme in two fundamental ways. First, they suggest the occurrences we outline would most likely happen in a few regions, rather than globally. Second, they say the magnitude of the event may be considerably smaller.

We have created a climate change scenario that although not the most likely, is plausible, and would challenge United States national security in ways that should be considered immediately.

National Security Implications of Abrupt Climate Change [PDF]