In this June 24, 2021 photo, a workman walks by an electrical substation in Bath that flooded in 2015, causing a major power outage. Credit: Troy R. Bennett / BDN

The U.S. is expected to experience as much sea level rise between now and 2050 as it had in the previous 100 years, with New England and Gulf of Mexico states predicted to see some of the highest flooding, according to a federal report released Tuesday.

The accelerated sea level rise related to climate change will bring more frequent and severe flooding, the report by the National Oceanic and Atmospheric Administration and other agencies found. It predicted an average sea level rise across the U.S. of 1.4 feet by 2050, which could increase the frequency of flooding 10 times.

Those figures are similar to estimates in Maine’s climate plan released in 2020, which foresees a sea level rise of 1.5 feet by 2050. The difference between the two estimates is not significant, state marine geologist Peter Slovinsky said. Maine will update its estimates next year.

Calling the new report data “a global wakeup call,” NOAA Administrator Rick Spinrad said the information can be used by coastal communities to make plans to keep people and property safe. How much people are vulnerable depends on where they live, Slovinsky said.

Just one foot of sea level rise means areas that flooded three or four times per year over the past decade will flood 10 to 15 times more frequently. Adding the sea level rise to a storm surge will compound potential damage.

“Adding sea level rise to a coastal storm doesn’t really seem like much, but it allows waves to be bigger and they will be superimposed on an elevated water level that isn’t usually reached right now,” Slovinsky said.

Besides damage to infrastructure and homes, floods can bring business and emergency services to a standstill. A torrential rain storm in late September 2015 coinciding with high tide waters and leaves clogging drains flooded an area near a low-lying Central Maine Power Co. substation in Bath, which had to shut off power to the utility’s 4,000 customers in and around the midcoast city.

Slovinsky said that 20 miles of public and private roads in Maine are at risk now of monthly tidal flooding, and if the sea level rises to the 4 feet predicted by the state in 2100, more than 115 miles will be at risk.

There also are health concerns with flooding. Saco’s wastewater treatment plant is one of several coastal locations that faces significant flooding from climate change. Environmental Protection Agency Administrator Michael Regan, who visited the York County city’s wastewater treatment on Monday, said “the risk of raw sewage overflowing in the Saco River is a threat to the community.”

Lori Valigra, investigative reporter for the environment, holds an M.S. in journalism from Boston University. She was a Knight journalism fellow at M.I.T. and has extensive international reporting experience...