The observed geographic pattern of adaptation demand has implications for understanding the consequences associated with specific climatic extremes, which are also heterogeneously distributed. This phenomenon was examined in the context of tropical cyclones. Estimates of historical direct economic losses at the U.S. county level from 19602008 were normalized to 2009 population and wealth using historical PSE and subsequently annualized. When those damages were scaled based upon county-specific projections of PSE, a U.S. commitment to future growth in economic losses due to tropical cyclones was apparent. Central estimates indicated increases in economic losses of 400600% by the mid-21st century. At the upper-end, however, losses were projected to increase by approximately 1,600%, consistent with insurance industry data suggesting losses double every 10 years. The implications of this committed vulnerability for adaptation demand depend upon assumptions regarding societal risk tolerance, autonomous adaptation, and discounting of future losses. For social discount rates of less than ~5%, the net present value (NPV) of future losses grows over the 21st century, suggesting greater near-term investments in hazard mitigation can be justified on cost/benefit grounds. Above discount rates of 5%, however, the NPV of future annual losses is constrained at or below contemporary levels, reducing demand for greater adaptation investments, and reinforcing the vulnerability commitment. Hence, the confident demonstration of the potential for future increases in the frequency, intensity, or duration of climate extremes may be necessary if institutions that employ relatively high discount rates in decision-making are to justify increased investments in anticipatory adaptation.
Given the apparent inertia of the U.S. socioeconomic landscape, reducing the rate of growth in future vulnerability will be dependent upon overcoming such barriers to action in pursuit of transformative adaptation policies and measures that systematically divert future development away from at-risk areas and/or substantially reduce the vulnerability of the built environment in situ. To the extent that the future growth in PSE is anticipated by institutions, there are likely to be significant opportunities for slowing the rate of growth of vulnerability by incorporating consideration for climate change into future development. Furthermore, while slow rates of PSE growth may be beneficial in one context, they may also reflect low adaptive capacity for coping with climate risk as a result of factors such as depopulation and/or lack of economic opportunity.