Sea Level Rise in Connecticut: Planning for 20 in/50 cm in 2050

By Rebecca A. French, Ph.D., CIRCA Director of Community Engagement

On October 19, 2017, CIRCA released an Executive Summary of its locally updated sea-level rise scenarios and recommendations on how Connecticut should adapt to the mean sea level changes projected in a 2012 National Oceanic and Atmospheric Administration report (Parris et al, CPO-1 Report, 2012):

“We recommend that planning anticipates that sea level will be 0.5 m (1ft 8 inches) higher than the national tidal datum in Long Island Sound by 2050. It is likely that sea level will continue to increase after 2050. We recommend that global mean sea level measurements and projections be monitored and new assessments be provided to towns at decadal intervals to ensure that planning be informed by the best available science.”(O’Donnell, Executive Summary, 2017)

It is important to note that the 20 in/50 cm planning level is not a prediction of the expected sea level increase by 2050, as has been reported in some recent newspaper articles. Rather, 20 in/50 cm characterizes the upper end of the range of values projected using several different simulation approaches and local tide gauge data sets. Together with the 10-year review, this is a prudent approach to providing planning guidance in a changing world.

On the CIRCA website (https://circa.uconn.edu/) the public can find the Executive Summary of the report and a 30-minute presentation by the report’s author and CIRCA Executive Director, Professor James O’Donnell. It provides a more in-depth explanation of his analyses and conclusions. The presentation shows how NOAA’s low, intermediate-low, intermediate and high global sea level rise projections were updated, and measurements from tide gauges in Long Island Sound were employed to create the recommendations.

More information can be found on our website or by contacting CIRCA staff directly at circa@uconn.edu.