The two parties disagree sharply about whether climate change can be considered a threat to our national security. A recent paper by Andrew Guzman (Berkeley) and Jody Freeman (Harvard) summarizes the support for this idea among serious students of national security:
In 2008, the National Intelligence Council produced the most comprehensive analysis to date of the implications of climate change for U.S. national security over the next twenty years. According to news reports, the classified assessment concluded that climate change could destabilize fragile political regimes, exacerbate conflicts over scarce resources, increase the threat of terrorism, disrupt trade, and produce millions of refugees—all of which would seriously affect U .S . national security interests.
As Guzman and Freeman explain, “[t]he consistent message of these studies is that while climate change . . . is certain to be a “threat multiplier,” exacerbating political instability around the world as weak or poor governments struggle to cope with its impacts.”
A recent report from RAND (here) stresses the importance of water as an intermediary between climate and security threats:
The most obvious of the political and social effects that might pose national security issues are those driven by water scarcity. . . . People moving across national borders to more water-hospitable environments can lead to tensions of many sorts. The migrants may find themselves stuck outside various cordons and fences; there may be recriminations against source countries for not securing their borders and ugly nativist backlashes in destination countries.
In particular, the report suggests, water issues in China could lead to conflict with Russia over water and land. Such a conflict could have destabilizing global impacts, not to mention the potential for escalation.
In my view, we should also factor in the possibility that climate change could hit the United States itself much harder than expected. There is no reason to think catastrophic outcomes in the U.S. are likely, but even very small odds of a terrible outcome deserve consideration.
In short, it is not at all fanciful to view climate change as a national security issue. It is short-sighted to assume that the U.S. will be unaffected by climate impacts in the rest of the world.