Adaptation to chronic and acute impacts ­ the case of coastal zone developments

In dealing with climate change impacts we can consider two classes of problems:

(i) acute problems due to occurrence of extreme events ­ which can and do happen for current climates, usually occur over a geographically limited area and are characterized by the need to provide rapid and massive relief
(ii) chronic problems due to subtle shifts in conditions (such as sea level rise) ­ these can and do happen under current conditions, but are expected to be more widespread and significant. The occurrence of these impacts is often not widely noticed and while the aggregate impacts are often much larger, rarely is relief sought in addressing chronic problems.

The paradox of the impacts and adaptation to acute and chronic impacts is amplified by the fact that because humans detect and respond to acute events, the occurrence of these can help reduce chronic problems by signaling the need to abandon vulnerable locations.

When considering the impacts of long-term coastal processes vis-à-vis infrequent extreme events it is important to note that on average, secular processes are far more damaging than extreme events. When extreme events do occur, though, the damage can be orders of magnitude higher than expected. We have developed a simulation model of households living in a hypothetical community on the east coast of the United States. This coastline experiences storms, long-shore drift, and relative sea level rise. The dynamics simulated in the model can lead to inundation and storm damages ­ both of which have been calibrated using insurance claims data. We are exploring the impacts of:

(i) sea level rise;
(ii) non-stationary storm climates; and,
(iii) regulations concerning set-back and regional development.

on the future patterns of development in this model of a coastal community. Our framework permits calculation of the incidence of private and social costs from sea level rise and storm regime changes. It also permits the exploration of costs and benefits of different regulatory approaches to management of risks from the sea in this community.