Identified concerns about climate-national security linkages, and associated research areas and needs, can be divided into two categories.
First, both climate change and efforts to respond to it may have significant effects on the operations, assets, and missions of the U.S. military. Many U.S. bases are located in areas that may be affected by sea level rise and tropical storms, and some future military operations may take place in areas subject to extreme high temperatures and droughts, compounding logistic problems. U.S. military operations are also substantial consumers of fossil fuels and thus will be affected by shifts in fuel prices and availability, as well as new technologies intended to displace fossil fuels.
Second, the impacts of climate change on specific assets and resources of international significance may affect multiple issues in bilateral and multilateral relations, shifting national strategic interests or perceptions thereof, or providing new bases for international conflict or cooperation. For example, declines in sea ice thickness and extent could result in increased access to and conflict over offshore resources in the Arctic Ocean associated with the opening of the Northwest and Northeast passages. Other examples include the effects of sea level rise and extreme events on coastal ports, navigable waterways, runways, roads, canals, or pipelines of international significance; changes in precipitation regimes that affect international river systems and ground vehicle mobility; and increases in humanitarian aid/disaster response stemming from changes in climate extremes (NRC, 2010e).
Climate change and responses to it may affect the U.S. military in several ways. The Department of Defense (DOD) was directed in 2009 by the U.S. Congress to include the potential impacts of climate change in their 2010 Quadrennial Defense Review (QDR). The QDR is a legislatively mandated review of DOD strategy and priorities that sets the long-term course for DOD by assessing the threats and challenges the nation faces and rebalancing the Department’s strategies, capabilities, and forces to address today’s conflicts and tomorrow’s threats. The QDR recognized climate change as one of many factors that has the potential to impact all facets of the DOD mission:
The rising demand for resources, rapid urbanization of littoral regions, the effects of climate change, the emergence of new strains of disease, and profound cultural and demographic tensions in several regions are just some of the trends whose complex interplay may spark or exacerbate future conflicts (DOD, 2010).