bathymetric data in the coastal seas, improved elevation data on land, the inclusion of wave and spillover effects, better data on precipitation rates and stream flows, ways of dealing with storm-driven sediment transport, and the ability to include the effects of built structures on coastal wind stress patterns.

Develop tools and approaches for understanding and predicting the vulnerability to, and impacts of, sea level rise on coastal ecosystems and coastal infrastructure, as well as for translating this understanding into decision-relevant information. The impacts of sea level rise on wetlands, coral reefs, marine fisheries, and estuarine bays and rivers need to be evaluated in concert with the impacts associated with increasing levels of CO₂ in the atmosphere and oceans, increasing nutrient inputs from land, and changes in use or management (see also Chapter 9). Likewise, the impacts of sea level rise on infrastructure, including ports, roads, cities, dikes, levees, and freshwater aquifers and storage facilities, should take into account potential shifts in storm patterns, rainfall rates, and other climate changes (see also Chapters 12 and 13). Improved valuation of nonmarket values, and development of decision-support tools to assess the trade-offs between physical, ecological, and social impacts and response options (see below) are needed to inform coastal management decisions that require long lead times.

Expand the ability to identify and assess vulnerable coastal regions and populations and to develop and assess adaptation strategies to reduce their vulnerability. With sea level rise acting in combination with other physical, social, and economic stressors, the ability to assess the social-ecological vulnerability of coastal regions, improve society’s adaptive response options (through technological, economic, and land use changes), and identify constraints to adaptation (including legal, social, political, infrastructure-related, and economic issues) are all critical research needs (see also Chapter 4). This area of research has received very little attention to date, leaving many U.S. coastal communities without adequate place-specific information to inform their adaptation decisions.

Develop decision-support capabilities for all levels of governance. Methods for identifying preferences and weighing alternative adaptive responses will be needed as environmental and social conditions change over time. Frameworks and approaches need to be developed for the evaluation of market and nonmarket values of affected assets and habitats; of the economic costs and other consequences of different response options to sea level rise on both highly developed and less developed shorelines; and of the social and environmental feasibility of different adaptation options (including technological, economic, physical, ecological, social, or legal options) for different coastlines. This will require improved information of the kinds listed