Thankfully, for the sake of those of us relying on them for our safety, the U.S. Department of Defense seems to understand both the difference between climate and weather and that an attempted assassination by 1,000 cuts cannot change the underlying truths of the IPCC's 2007 climate assessment.

In its recently released Quadrennial Defense Review (QDR), the DoD states, "Climate change and energy are two key issues that will play a significant role in shaping the future security environment." No debate. According to the U.S. security apparatus, these are issues that the U.S. security apparatus will have to deal with.

The QDR states two "broad" ways in which climate change will affect U.S. security. Global warming will "shape the operating environment, roles, and missions that we undertake", and DoD will be forced to deal with "the impacts of climate change on our facilities and military capabilities."

The QDR doesn't blink:

The U.S. Global Change Research Program, composed of 13 federal agencies, reported in 2009 that climate-related changes are already being observed in every region of the world, including the United States and its coastal waters. Among these physical changes are increases in heavy downpours, rising temperature and sea level, rapidly retreating glaciers, thawing permafrost, lengthening growing seasons, lengthening ice-free seasons in the oceans and on lakes and rivers, earlier snowmelt, and alterations in river flows.

What effects does this have on American national defense? The QDR continues:

Climate change will contribute to food and water scarcity, will increase the spread of disease, and may spur or exacerbate mass migration. While climate change alone does not cause conflict, it may act as an accelerant of instability or conflict, placing a burden to respond on civilian institutions and militaries around the world. In addition, extreme weather events may lead to increased demands for defense support to civil authorities for humanitarian assistance or disaster response both within the United States and overseas.

Note the certainty. Climate change "will" cause resource scarcity and "will" cause the spread of disease.  For the DoD, these changes have a two-pronged effect, as an "accelerant" of instability and conflict, as well as an increased burden on the military to engage in humanitarian assistance, limiting its ability to focus solely on defense.

Second, not only will our defense apparatus be forced to deal with more, increasingly complex, security issues, our defense infrastructure is at risk.  As an example, "In 2008, the National Intelligence Council judged that more than 30 U.S. military installations were already facing elevated levels of risk from rising sea levels." Among other things, this is a security risk -- "DoD’s operational readiness hinges on continued access to land, air, and sea training and test space."

What's encouraging is that the U.S. security apparatus not only recognizes the risk but is also prepared to act to help mitigate that risk.   

1. First, they're going to improve assessment:  "Domestically, the Department will leverage the Strategic Environmental Research and Development Program, a joint effort among DoD, the Department of Energy, and the Environmental Protection Agency, to develop climate change assessment tools."
2. Second, the DoD is going to help others adapt to the effects of climate change that we now can't avoid in an attempt to reduce the humanitarian burden when disaster strikes. 
3. Third, the DoD is going to share technology: "The Department will also speed innovative energy and conservation technologies from laboratories to military end users. The Environmental Security and Technology Certification Program uses military installations as a test bed to demonstrate and create a market for innovative energy efficiency and renewable energy technologies coming out of the private sector and DoD and Department of Energy laboratories."
4. Finally, the DoD is going to get its own house in order by pushing efficiency and renewable energy projects at military installations through the "Energy Conservation Investment Program."