A flexible and national scale approach to coastal decision tools incorporating sea level rise

Abstract:

Climate science and sea level models constantly evolve. In this context, maps and analyses of exposure to sea level rise -- or coastal flooding aggravated by rise -- quickly fall out of date when based upon a specific model projection or projection set. At the same time, policy makers and planners prefer simple and stable risk assessments for their future planning. Here, using Climate Central’s Surging Seas Risk Finder, we describe and illustrate a decision tool framework that separates the spatial and temporal dimensions of coastal exposure in order to help alleviate this tension. The Risk Finder presents local maps and exposure analyses simply as functions of a discrete set of local water levels. In turn, each water level may be achieved at different times, with different probabilities, according to different combinations of sea level change, storm surge and tide. This temporal dimension is expressed in a separate module of the Risk Finder, so that users may explore the probabilities and time frames of different water levels, as a function of different sea level models and emissions scenarios. With such an approach, decision-makers can quickly get a sense of the range of risks for each water level given current understanding. At the same time, the models and scenarios can easily be updated over time as the science evolves, while avoiding the labor of regenerating maps and exposure analyses.

In this talk, we will also use the tool to highlight key findings from a new U.S. national assessment of sea level and coastal flood risk. For example, more than 2.5 million people and $500 billion dollars of property value sit on land less than 2 meters above the high tide line in Florida alone.