At a Glance
- Between 10 and 12 inches of sea level rise is expected on U.S. coastlines, the report said.
- Some areas will see even higher amounts.
- Rising sea levels mean more flooding, even on days without storms or heavy rainfall.
A century's worth of sea level rise is expected in the United States within the next 30 years, according to a new report from the National Oceanic and Atmospheric Administration and other federal agencies including NASA and the EPA.
The Sea Level Rise Technical Report, released Tuesday, projects that sea levels along U.S. coastlines will rise 10 to 12 inches by 2050, with higher numbers in some locations. The numbers are equivalent to those seen over the entire previous 100 years.
On average, 10 to 14 inches of sea level rise is expected for the East Coast, 14 to 18 inches along the Gulf Coast, 4 to 8 inches on the West Coast, 8 to 10 inches in the Caribbean, 6 to 8 inches for the Hawaiian Islands and 8 to 10 inches in northern Alaska.
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Higher sea levels mean more coastal flooding — even on days without storms or heavy rainfall.
“By 2050, moderate flooding — which is typically disruptive and damaging by today’s weather, sea level and infrastructure standards — is expected to occur more than 10 times as often as it does today,” NOAA National Ocean Service Director Nicole LeBoeuf said in a news release. “These numbers mean a change from a single event every 2-5 years to multiple events each year, in some places.”
Overall, at least 2 feet of sea level rise is likely by 2100, according to NOAA.
Sea level rise increases the rate of coastal flooding from high tides, also known as "nuisance flooding." It can also make the impacts of extreme weather worse by pushing deadly and destructive storm surges farther inland.
Sea level rise is fueled by ocean warming and higher atmospheric temperatures that cause ocean water to expand and glaciers and ice sheets to melt. Global warming caused by greenhouse gas emissions drives higher temperatures.
The differences in amounts by location are mostly due to changes in land height, according to the NOAA report. In some areas, the land is subsiding at the same time sea levels are rising. Other local factors, including erosion and ocean currents, can also impact the amount of sea level rise locally.
NOAA and other agencies collect local data from tide stations around the world and analyze satellite data to gauge sea level rise in oceans.
The findings released Monday, an update from a 2017 report, also looked at model ensembles from the United Nations' Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
“This report supports previous studies and confirms what we have long known: Sea levels are continuing to rise at an alarming rate, endangering communities around the world," said NASA Administrator Bill Nelson. "Science is indisputable and urgent action is required to mitigate a climate crisis that is well underway."
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