300,000 coastal homes in US, worth $120 billion, at risk of chronic floods from rising seas

Hundreds of thousands of homes along U.S. coasts are at risk of devastating coastal flooding over the next 30 years as climate change causes oceans to rise, according to a new study.

About 311,000 coastal homes, worth about $120 billion, are at risk of chronic flooding, the Union of Concerned Scientists, a science advocacy group, said in the report released Monday.

By the end of the century, homes and businesses currently worth more than $1 trillion — including those in Miami, New York's Long Island and the San Francisco Bay area — could be at risk.

"This risk is relatively near-term, well before places go underwater completely, and even in the absence of storms," Rachel Cleetus, lead economist with the group, told Agence France-Presse. "This is a slow-moving disaster."

"In contrast with previous housing market crashes, values of properties chronically inundated due to sea level rise are unlikely to recover and will only continue to go further underwater, literally and figuratively,” Cleetus said.

States with the most homes at risk by the end of the century are Florida, with about 1 million homes (more than 10 percent of the state's current residential properties); New Jersey, with 250,000 homes; and New York with 143,000 homes.

“The federal government has become its own disaster area, so we have to assume we are on our own for the time being," said Philip Stoddard, the mayor of South Miami, Florida. "At the local level, coastal communities must no longer allow construction that cannot accommodate sea level rise," he said.

The seas are rising as heat-trapping greenhouse gases from burning fossil fuels cause glaciers and ice sheets in Greenland and Antarctica to melt. Warmer water takes up more space that cooler water or ice, causing sea levels to rise.

Since 1880, the ocean has risen nearly 8 inches worldwide, according to the Union of Concerned Scientists, but it hasn't done so evenly. In the past 100 years, it's climbed about a foot or more in some U.S. cities.

“For some communities, the potential hit to the local tax base could be staggering,” said Kristy Dahl, senior climate scientist at Union of Concerned Scientists and the report's co-author. “Some smaller, more rural communities may see 30, 50, or even 70 percent of their property tax revenue at risk due to the number of chronically inundated homes."

The report is based on what would happen if sea levels rose from less than a foot in the near future to as high as nearly 8 feet by 2100.

"Whether we react to this threat by implementing science-based, coordinated, and
equitable solutions — or walk, eyes open, toward a crisis — is up to us right now," the report concluded.

WSBTV