Momentum to consider climate and security connections has been growing over the last few years, with the United States lagging behind. The Europeans long ago jumped on these connections. And numerous developing countries -- Egypt, Bangladesh, and small island states, to name only a few -- view expected sea level rise from global warming as an ultimate security threat to the survival of large swathes of territory and tens of millions of people. Facing the prospect of longer and deeper droughts, countries in the Horn of Africa are also coming to recognize these fundamental threats to the national interest. In the United States, Hurricane Katrina provided a glimpse of what a warmer world may be like, the experience of which, it could be argued, made its way into the 2006 revision to the U.S. National Security Strategy.

The key passage, admittedly at the end of the document, explains that environmental destruction -- caused by humans or nature -- presents new security challenges:

Problems of this scope may overwhelm the capacity of local authorities to respond, and may even overtax national militaries, requiring a larger international response. These challenges are not traditional national security concerns, such as the conflict of arms or ideologies. But if left unaddressed they can threaten national security.

(More at NewSecurityBeat.)