Objective

Pacific islands face multiple climate-related threats, including tropical cyclones, droughts, floods, and increased rates of sea-level rise. Understanding and preparing for how future climate change may affect freshwater resources and contribute to loss of coastal land, including protective landforms such as barriers, dunes, and reefs, present significant challenges facing Department of Defense (DoD) resource managers and planners. Coastal landforms in the Pacific, including entire atoll systems, are perceived to be vulnerable to anticipated climate change. Among the predicted impacts are: inundation, coastal erosion, salinity intrusion, loss or alteration of ecosystems, and changes in the frequency of extreme events (e.g., typhoons, floods, and droughts). The degree of sensitivity, however, likely varies considerably depending on antecedent conditions that created the landforms and the direction, magnitude, and spatial expression of future climate change. Even sea-level changes will have local and regional signals related to changes in large-scale wind and wave fields and vertical land movements that may be as large as mean global changes. Although both tropical cyclone frequency and intensity is often predicted to change, the spatial pattern of these shifts is likely to affect some locations more than others. Islands that are particularly vulnerable to tropical cyclones are likely ones that have not experienced considerable tropical cyclone impacts in their recent geological history, but are forecast to see significant increases in activity. Intense storms can be both destructive (causing erosion) and constructive (causing aggradation or progradation) to the evolving, natural infrastructure of islands; however, in terms of fixed human infrastructure they are often destructive. Thus, although a landform might be resilient to future climate change stressors, such as changes in storminess and sea level, the fixed assets on these landforms may be quite vulnerable. 

The objective of this project is to provide probabilistic information on potential climate-related threats for DoD installations across the Pacific over the next century, including those that might arise from hydrological changes, sea-level change, and changes in tropical cyclone activity.