ACCELERATING SEA LEVEL RISE AND STAKEHOLDER RESPONSE

The region between Cape Hatteras and Cape Cod is experiencing accelerating sea level rise. This paper will discuss the evidence for and predictions of sea level rise followed by the needs of stakeholders such as regional planners and civil engineers.

Sallenger, Doran and Howd (2012) and Ezer and Corlett (personal communication) have shown strong evidence for the acceleration of sea level rise in the 0.05 – 0.1 mm y^-2 range rather than a simple linear increase. They attribute this to changes in the dynamic sea level rise component such as wind field and North Atlantic Ocean dynamic features such as the Gulf Stream (Ezer, 2001). Sweet, Zervas and Gill(2009) attributed the anomalously high sea level along the mid-Atlantic in 2009 to dynamic SLR. These accelerations suggest that the higher estimates of SLR in IPCC reports may be better estimates. Even if the strength and frequency of storms remains steady, rising sea level will result in increased damage.

We will give several examples of how stakeholders are dealing with increased flooding risk due to sea level rise: cities, NASA facilities, and shipyards.

Regional planners and engineers require estimates of local sea level out 50 to 100 years as that is the lifetime of coastal infrastructure: docks, piers, levees, etc. They also require error bars on these estimates. Studies of dynamic SLR are required to provide this information.

Emergency managers also need short term predictions of flooding risk. In 2009 sea level along the northeast U.S. coastline remained around 0.3 m above predicted for months. Rising sea level will acerbate the effects of these short term fluctuations. Predicting such shorter term variations in sea level just as we observe and predict the ENSO cycle may become necessary for disaster preparation.

Finally we will discuss how flood insurance rates are subsidized and do not reflect the true risk of coastal flooding and do not incorporate the likelihood of future sea-level rise.