Coastal sea levels in US to rise a foot by 2050, study confirms

The study also found that, at the current rate of warming, at least 2 feet of sea level rise is expected by the end of the century

The report, an update of a 2017 study, has relatively precise estimates of sea level rise by 2050. Credit: AFP File Photo

Sea levels along the coastal United States will rise by about 1 foot or more on average by 2050, government scientists said Tuesday, with the result that rising water now considered “nuisance flooding” will become far more damaging.

A report by researchers from the National Oceanic and Atmospheric Administration and other agencies also found that, at the current rate of warming, at least 2 feet of sea level rise is expected by the end of the century.

“What we’re reporting out is historic,” Rick Spinrad, the NOAA administrator, said at a news conference announcing the findings. “The United States is expected to experience as much sea level rise in the next 30 years as we saw over the span of the last century.”

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Spinrad said that while cutting greenhouse gas emissions to limit warming is critically important, the projected sea level rise by 2050 “will happen no matter what we do about emissions.”

The report, an update of a 2017 study, has relatively precise estimates of sea level rise by 2050, a result of improved computer modeling and better understanding of the impact of global warming on the huge Greenland and Antarctic ice sheets. That is “providing more confidence in our ability to predict” effects by midcentury, said William Sweet, an oceanographer with NOAA’s National Ocean Service and an author of the report.

About 40% of the U.S. population, or 130 million people, live within 60 miles of the ocean. But sea level rise will not affect all of them equally because it is not uniform.

In the United States, land subsidence and compaction of sediments along much of the East and Gulf coasts add to the increase; in those areas, sea level rise may exceed 1 foot in the next three decades, the report said.

Many communities on those coasts experience regular “nuisance” flooding, when high tides become even higher because of the influence of the moon, wind or other factors.

But what were once nuisance floods are likely to become damaging, Sweet said. “We definitely are predicting a flood regime shift,” he said.

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