CLIMATE CHANGE, COASTAL GEOLOGIC HAZARDS AND SEA-LEVEL RISE: SOME RHODE ISLAND STRATEGIES

When assessing the effects of climate change on the shore, it is necessary to separate the impact of geologic hazards, tropical and extratropical cyclones, from the impact of sea-level rise. The recently released IPCC (2011) special report on managing risks of extreme events indicates that there is a 66-100% probability that intensity of tropical cyclones (hurricanes) will increase in the coming years. This means that hurricane strikes in southern New England will result in increased frontal erosion and elevated storm surge that will inundate the shore zone further inland. An increased frequency of extreme precipitation events means higher intensity extratropical cyclones (northeasters) for southern New England. Again, the result will be increased frontal erosion and elevated storm surge.

Sea-level rise at Newport, RI measured 25.6 cm^.100yr^-1 from 1931-2009, the rate increased to 36.2 cm^.100yr^-1 for 1990-2009, comparable to published global eustatic rates. Published extreme modeled rates of sea-level rise using IPCC (2007) predictions of atmospheric temperature increase as the driver, suggest eustatic sea-level rise of up to 190 cm by 2100. Adding to sea-level rise concerns is the instability of the Greenland Ice Sheet, particularly the interaction of a rising and warming sea with the outlet glaciers (IPCC, 2010). An extreme outcome would be a rapid downdraw of Greenland ice giving a meltwater pulse similar to Meltwater Pulse 1B that resulted in a conservative sea-level rise rate of 2 meters per 100 years.

The Rhode Island response has been to incorporate extreme event and accelerated sea-level rise planning at the State and municipal levels to identify infrastructure at future risk and explore adaption strategies now. Little Rhody “gets it”.