Sea Level Rise

CIRCA works to enhance coastal resilience to sea level rise in Connecticut. Sea level change is caused by a number of factors summarized in the figure on the right (click to enlarge), but in recent decades ocean warming and ice sheet loss due to global warming have contributed significantly to global sea level rise. Along the east coast, including Connecticut, sea level rise rates are more rapid than the global average rate because of subsidence or sinking of the coastline.

Sea Level Rise and Coastal Flooding and Inundation in Connecticut

The rates of sea level rise in Connecticut can be measured directly from tide gauges in New London and Bridgeport. The rates of these local gauges are higher than the global average based on tide gauge data of 3.2 mm/year since records started to be collected in 1900. One established source of this more rapid rate of rise is subsidence.

Sea level rise has multiple impacts on the Connecticut shoreline, including increased erosion rates, increased frequency of flooding, and coastal inundation. As sea levels rise the shoreline responds and beaches get eroded away and the coastline moves back. Other coastal features, like salt marshes, also migrate landward. With a relative higher sea level, a storm surge or high tide, that would not have been a problem in the past, now results in flooding. Inundation is the permanent drowning of our coastline. In the short-term the increase of 8 inches in sea level that we have already experienced since the mid-1800s is not as noticeable against the daily tides, however if sea level continue to rise at a rapid rate, the shoreline can expect to see somewhere between 8 inches and 6.6 feet of sea level rise by the end of the century. Although they are not accurate enough to make localized predictions of the impacts of sea level rise, there are multiple mapping tools available that can help communities visualize future sea level inundation.

CIRCA and Sea Level Rise

Public Act 13-179, “An Act Concerning the Permitting of Certain Coastal Structures” calls for the consideration of sea level rise as referenced in NOAA CPO-1 report in the plan of conservation and development and municipal evacuation or hazard mitigation plans. The Act also charges the Department of Marine Sciences to update the NOAA sea level rise scenarios. The NOAA sea level rise projections are a global average. CIRCA will provide sea level rise statistics at the local scale for Connecticut’s shoreline.

CIRCA Research Projects

CIRCA’s current research projects in the area of sea level rise are listed below.

Municipal Resilience Planning Assistance for Sea Level Rise, Coastal Flooding, Wastewater Treatment Infrastructure, & Policy

The Municipal Resilience Planning Assistance for Sea Level Rise, Coastal Flooding, Wastewater Treatment Infrastructure, and Policy project provides information for wastewater system vulnerability assessments, combined river and coastal flooding for pilot sites, and policy options for priority resilience projects for towns in the Sandy-impacted counties.

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sea level rise illustration
(Click image to enlarge) The factors that contribute to sea level change, both on land and in the sea. Source: IPCC (2001)


Further Reading