Global and Regional Sea Level Rise Scenarios for the United States

This technical report updates scenarios of Global Mean Sea Level (GMSL) rise, and then integrates regional factors with these global scenarios for the entire U.S. coastline. It was produced by the Sea Level Rise and Coastal flood Hazard Scenarios and Tools Interagency Task Force, convened by the U.S. Global Change Research Program (USGCRP) and the National Ocean Council. 

These scenarios and tools are intended to serve as a starting point for on-the-ground coastal preparedness planning and risk management processes, including compliance with the new Federal Flood Risk Management Standard. While the first few sections are primarily scientific and technical describing the research and the results of the analysis, Section 6 is geared more toward the needs of users for applying these results in planning processes.

The new sea level scenario products are presented from a risk-based perspective, with a goal to identify appropriate scenarios to support evaluation and management of future risks associated with sea level rise. To ensure consistency with recent updates to the peer-reviewed scientific literature, the Task Force recommends a revised ‘extreme’ upper-bound scenario for GMSL rise of 2.5 m by the year 2100, which is 0.5 m higher than the upper bound scenario from Parris et al. (2012) employed by the Third National Climate Assessment (NCA3).

Key findings include:

  • Along regions of the Northeast Atlantic (Virginia coast and northward) and the western Gulf of Mexico coasts, RSL rise is projected to be greater than the global average for almost all future GMSL rise scenarios (e.g., 0.3-0.5 m or more RSL rise by the year 2100 than GMSL rise under the Intermediate scenario).
  • Along much of the Pacific Northwest and Alaska coasts, RSL is projected to be less than the global average under the Low-to-Intermediate scenarios (e.g., 0.1-1 m or less RSL rise by the year 2100 than GMSL rise under the Intermediate scenario).
  • Along almost all U.S. coasts outside Alaska, RSL is projected to be higher than the global average under the Intermediate-High, High and Extreme scenarios (e.g., 0.3-1 m or more RSL rise by the year 2100 than GMSL rise under the High scenario).

 

Publication Date: January 2017

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