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Scientists expect more frequent and severe storms to create a higher flood risk over the next 30 years, which in turn will cause Mainers and people across the United States to leave or avoid so-called “climate abandonment areas,” new research published Monday in the journal Nature Communications said.
Those areas already have lost population, and new risk areas, particularly along the coasts and rivers, will emerge over the next 30 years, the research by Brooklyn-based nonprofit First Street Foundation predicted.
In the years from 2000 to 2020, some 3.2 million fewer Americans lived in climate abandonment areas. That is projected to increase to 5 million fewer residents in the emerging abandonment areas over the next 30 years. Other low-risk flood areas are expected to gain population.
“The downstream implications of this are massive and impact property values, neighborhood composition and commercial viability both positively and negatively,” Jeremy Porter, head of climate implications research at First Street, said.
Areas that have been developed in Maine and elsewhere in the U.S. over the past 20 years that were considered safe are now seeing the effects of climate change and the increased flooding risk that comes with it, the research found.
In Maine, Waldo County is one of the most at-risk areas when looking at significant flood risk and lost population from 2000 to 2020, Payne said. Most of the areas are along the rivers where they feed into larger water bodies. The area with the most risk, he said, is in Belfast along the Passagassawakeag River where it feeds into Belfast Bay.
Lincoln, Hancock, Sagadahoc and Washington counties also showed high risks in those 20 years. Penobscot, Piscataquis, Somerset and York counties showed some of the lowest risk.
First Street looked at U.S. Census data on population shifts and Census blocks, or clusters of typically 250-550 housing units within a geography.
It found that about 20 percent of Census blocks in Waldo County had climate abandonment areas with frequent flooding from 2000 to 2020, among the highest amount in the state. The study predicted close to 26 percent of the blocks would become new climate abandonment areas from 2020 to 2053 that people would leave or avoid.
In the Belfast Bay area, 77 climate abandonment areas aligned with high flood risk from 2000 to 2020, Porter said. Those areas had 2,567 people living in them in 2000 and 1,889 in the year 2020, a decline of 678. Porter said that 201 of that decline in population could be attributed to the high flood risk.
Belfast Mayor Eric Sanders said he isn’t seeing people leave Belfast, a town of about 7,000 residents, but instead has seen the midcoast filling up. He said efforts by the town, including its Climate Crisis Committee, should help mitigate the effects of sea level rise.
Porter does not expect Maine to suffer the severe consequences of low-lying areas of the United States like the barrier island of Isle De Jean Charles in Louisiana, where the federal government is helping fund relocation of the entire population as the island succumbs to rising sea levels and climate change. But towns and cities in Maine still need to focus on short-term adaptation to mitigate the effects of rising sea levels and storm flooding, he said.
Towns across Waldo County already are updating their flood zone plans, including looking at storm water management and problems with improperly designed culverts, Dale Rowley, director of the Waldo County Emergency Management Agency in Swanville, said.
Much of the flooding in Belfast is concentrated from the boathouse to the large bridge downtown. The city has hired an engineering firm to study stormwater impacts. It also is working on a hazard mitigation plan, including possibly fortifying the breakwater to help prevent damage.
“We have not seen people migrate out, but we are keeping an eye on the impacts of climate change in our bay. It needs to be taken seriously,” Erin Herbig, Belfast city manager, said. “We’re really trying to stay ahead of it rather than being reactive.”
Lori Valigra is an investigative environment reporter for the Bangor Daily News Maine Focus team. She may be reached at [email protected]. Support for this reporting is provided by the Unity Foundation and donations by BDN readers.
