Updated Sea Level Rise Projections for U.S. Coastlines

The U.S. Sea Level Rise and Coastal Flood Hazard Scenarios and Tools Interagency Task Force, composed of representatives from several government agencies and academic institutions such as the National Oceanic and Atmospheric Administration, the Environmental Protection Agency, and the U.S. Army Corps of Engineers released an updated sea level rise technical report. Titled Global and Regional Sea Level Rise Scenarios for the United States, the report updates a previous 2017 report and offers sea level rise projections through the year 2150 along with short-term forecasts for the next 30 years. Federal, state, and local governments can use this information to guide their plans to prepare for and adapt to imminent rising sea levels.

Overall, the report concludes that sea levels along U.S. coastlines will rise between 10 to 12 inches (25 to 30 centimeters) on average by 2050, increasing the risk of coastal flooding, the destruction of delicate ecosystems, and possible damage to critical infrastructure such as roads, public utilities, and structural foundations. This exemplifies the alarming rate with which sea levels are rising because in the continental U.S., relative sea level has risen about the same amount in the last hundred years, and the global mean sea level has only risen 6 to 8 inches (15 to 20 centimeters) in the same period.

According to the authors, the two major causes of global mean sea level rise are thermal expansion (the expansion of ocean water as it warms) and the added water from melting land-based ice (e.g., glaciers), both of which are driven by increased global temperatures associated with greenhouse gas emissions. Because of this, this report will provide key technical information for the Fifth National Climate Assessment (NCA5).

To check out projected sea levels near your area, check out the Interagency Sea Level Rise Scenario Tool here.

For more information on topics related to this piece, visit the HSDL Featured Topic on Climate Change, or check out some of the many HSDL documents about rising sea levels.

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