Latest Projections of Regional Sea Level Rise Emphasize Need for Ongoing Research, Adaptation Planning

Our rapidly warming climate has profound geophysical, ecological and biological, as well as socioeconomic, impacts worldwide. Glacial melt, for instance, is changing the shape and raising the elevation of land masses, while rising sea levels threaten the sustainability of coastal cities and communities, reshape ocean basins and alter the Earth’s rotation and gravitational field.

Gathering, organizing and analyzing all the scientific data required to monitor and assess the effects of climate change and rising sea levels and craft even adequate adaptation plans is a huge, complex – and essential – task. It’s only recently that scientists have been able to develop climate change models that can produce regional projections of sea level rise with the necessary degree of confidence, and these efforts continue today.

On Jan. 19, NOAA and partners published new scenarios and projections for global and regional U.S. sea level rise out to 2100 and 2200, affording coastal communities across the U.S. the data information needed to craft better climate change plans and adapt to the risk of and threats posed by rising sea levels.

Six scenarios

Refining six scenarios of global sea level rise culled from the latest published and peer-reviewed scientific research to a gridded resolution of one degree (about 70 miles), scientists from NOAA, NASA, universities and research institutes around the country were able to produce probabilistic estimates of sea level rise for U.S. coastal regions by decade out to 2100 and over longer time frames out to 2200.

The unprecedented degree of resolution enables coastal managers in Mobile, Alabama and Miami, Florida to produce probabilistic estimates, assess different outcomes and craft local adaptation plans using the same scenario, NOAA highlights in a news release.

State coastal planners in the mid-Atlantic and Gulf of Mexico regions have used similar methods to assess the risks global and regional sea level rise poses to U.S. military installations worldwide, NOAA notes.

“The ocean is not rising like water would in a bathtub,” explained William Sweet, Ph.D., a NOAA oceanographer and lead author of the report detailing the scenarios. “For example, in some scenarios sea levels in the Pacific Northwest are expected to rise slower than the global average, but in the Northeast they are expected to rise faster.

“These scenarios will help communities better understand local trends and make decisions about adaptation that are best for them.”

NOAA highlights the following among the report’s key takeaways:

• 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).

“Global and Regional Sea Level Rise Scenarios for the United States,” was produced by a joint public-private sector for the Sea Level Rise and Coastal Flood Hazard Scenarios and Tools Interagency Task Force, an agency created by the U.S. Global Change Research Program and National Ocean Council in 2015. Researchers from NOAA, Rutgers University, the Environmental Protection Agency (EPA), South Florida Water Management District, Columbia University, and U.S. Geological Survey co-authored the report.

*Image credits: NOAA, et. al., “Global and Regional Sea Level Rise Scenarios for the United States”; Jan. 2017