"Climate Extremes: Recent Trends with Implications for National Security"

Last year, I participated in a few workshops where we thought through some of the "worst case scenarios" as well as potential mechanisms through which climatic changes could influence US national security interests in the next decade or so. The report (which I did not write) is now out (here, article here). The authors are trained geoscientists, so the text is focused on the physics side of the problem.

CLIMATE EXTREMES AND NATIONAL SECURITY – THE BOTTOM LINE
Climate change has entered the mainstream as a potential threat to U.S. national security. The 2010 Quadrennial Defense Review, and the 2010 National Security Strategy all identify climate change as likely to trigger outcomes that will threaten U.S. security. These assessments have had to rely on projections of climate change tuned to identify impacts over roughly a one-century time frame. This time frame is driven by the nature of the questions that dominated the initial literature (e.g., what impacts can  be expected from a doubling of pre-industrial carbon dioxide) and the fact that global climate models are generally able to resolve expected impacts only over large scales and the long term.Having arrived at a condition where climate change has been identified as a likely threat to U.S. national security interests, but with little ability to clarify the nature of expected climate impacts over a timeframe that is relevant to security decision-makers, the authors decided to focus on the near-term impacts from climate change (over the next decade). In short, the analysis finds that, absent unknown or unpredictable forces, the increase in extreme events observed in the past decade is likely to continue in the near term as accelerated warming and natural variability combine to produce changing weather conditions around the world. This will impact Water Security, Energy Security, Food Security, and Critical Infrastructure, and brings into focus the need to consider the accelerating nature of climate stress, in concert with the more traditional political, economic, and social indicators.

Some people may think the headlines from the report sound alarmist (I'm just guessing), but I think the text is quite pragmatic:

What was once a 1 in 100 year anomaly is likely to become a 1 in 10 or 1 in 30 year anomaly or even more frequent in the near future. Our infrastructure and agriculture is not designed to accommodate  the increasing frequency and prevalence of such extremes. Human security and the interests of most nations are at stake as a result of such increasing  climate stress. The national security context will change. The potential for profound impacts upon water, food and energy security, critical infrastructure, and ecosystem resources will  influence the individual and collective responses of nations coping with climate changes. U.S. national security interests have always been influenced by extreme weather patterns. Now the risks will become larger and more apparent. The study renders the judgment that the increasingly disruptive influences of climate extremes necessitate their careful consideration in threat analysis, mitigation, and response. It is in the best interest of the U.S. to be vigilant about extreme weather patterns, the behavior of nations in their attempts to mitigate or adapt to the effects of changing extremes, and impacts on social, economic, and political well-being.

h/t Center for Climate and Security