Sea Level Rise Scenarios for the United States

In January 2017 NOAA published the technical report Global and Regional Sea Level Rise Scenarios for the United States. Key findings include:

• For almost all future GMSL (global mean sea level) rise scenarios, RSL (relative sea level) rise is projected to be greater than the global average along the coasts of the U.S. Northeast and the western Gulf of Mexico.  
• Under the Intermediate and Low GMSL rise scenarios, RSL is projected to be less than the global average along much of the Pacific Northwest and Alaska coasts.  
• Under the Intermediate-High, High and Extreme GMSL rise scenarios, RSL is projected to be higher than the global average along almost all U.S. coasts outside Alaska.

The report also mentions consequences of RSL rise that are already occurring such as increasing tidal-flood frequencies in coastal communities. Using as a definition of flood-frequency the elevation threshold of about 0.8 m (2.6 feet) above the highest tide with a local 20% annual chance of occurring, annual frequencies of damaging flooding with less than 14 inches of local RSL rise "will increase 25-fold by or about (±5 years) 2080, 2060, 2040 and 2030 under the Low, Intermediate-Low, Intermediate, and Intermediate High subset of scenarios, respectively."

See the full report at https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf


NOAA also has a new mapping tool to visualize community-level impacts from coastal flooding or sea level rise (up to 6 feet above average high tides). Try the new beta version.