contingent causal pathways in between. This chapter is intended to explore the evidence that the social sciences can add to our understanding of the connections between climate events and major security-relevant outcomes. It is not possible in this study to examine all possible links, so this chapter examines a selection of some of the most commonly mentioned relationships. It begins with an examination of the connections between climate events and some of the major outcomes—such as threats to water, food, and health security; humanitarian crises; and disruptive migration—that are frequently cited in the policy literature, and it then discusses traditional security outcomes, such as political instability and interstate and internal conflict.


Water Security

Basics of Supply and Demand

The fundamental role that water plays in sustaining and supporting life, a healthy environment, and human well-being is drawing high-level international attention to the availability and quality of water as an essential component of development. Increasing access to safe drinking water and basic sanitation is a key component of the Millennium Development Goals (United Nations, 2012), and the period 2005–2015 was named as the United Nations International Action Decade “Water for Life.”1 More fundamentally, water is essentially irreplaceable. With other resources, such as energy and food resources, there are a number of substitutes that can be used to meet the societal needs for these resources. Currently, however, water can only be replenished at costs that are beyond the reach of many of the most water-stressed countries. Conflict over water availability or caused by issues related to delivery of water resources to meet competing needs of energy, food, and health thus have the potential to define critical climate-related conflicts and relief challenges across the globe.

Projections of future availability of freshwater suggest increasing imbalances between supply and demand. Between 1970 and the mid-1990s the amount of economically available water per person dropped by more than 35 percent (United Nations, 1997, quoted in Wolf, 2007:242), and one frequently quoted estimate (2030 Water Resources Group, 2009) projects a gap of 40 percent between global water requirements and accessible, reliable water supply by 2030. “This global figure is really the aggregation of a very large number of local gaps, some of which show an even worse situa-


1 See (accessed July 5, 2012).

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