Climate report details flood risk

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Washington: The nation’s capital is likely to see record flooding by 2050, putting about $7 billion worth of property, three military bases and parts of the National Mall at risk as a result of climate change that is raising sea levels all over the world, according to a report released Tuesday by the research group Climate Central.

That is one of the group’s more conservative estimates in a report titled “Washington, D.C., and the Surging Sea.”

In the worst case, the group draws an end-of-the-century picture of the Lincoln and Jefferson memorials as islands in a flooded Potomac River, and Fort McNair, the Washington Navy Yard and parts of Joint Base Anacostia-Bolling completely under water.

Scientists’ warnings about the effects of climate change are not new, with predictions that melting polar ice will lead to a rise in sea levels that will lap around the edges of New York, turn Houston into a latter-day Venice and force millions of residents in low-lying nations like Bangladesh out of their homes.

The dangers to Washington are acute, the report said. Contrary to popular myth, the city was not built in a swamp, but it is in a flood plain, and its officials and engineers have tamed the wild Potomac. Those advances could be turned back as the seas rise, the report said. And that may affect the nation well beyond the District of Columbia’s boundaries.

“The monument area and the Mall are in some ways the soul of Washington, D.C., so to see those areas flooding, I think, will probably have an important emotional and cultural effect, as well as a physical effect,” said Ben Strauss, director of Climate Central’s Program on Sea Level Rise and the report’s lead author. A sea-level increase of about 4 feet by the end of the century would most likely lead to at least one damaging flood more than 8 feet above high tide, the study says. The current record of 7.9 feet was set in 1942.

The study’s lowest estimate, which accounts for a rise in the sea level of just 1 1/2 feet, predicts flooding more than 6 feet above high tide in just 16 years, akin to some of the most severe floods the city has seen. Just four floods have exceeded 6 feet since 1931.

“You could go from a situation where you buy a home, it’s never been flooded before in memory, it’s a low flood risk,” Strauss said. “And by the time you pay off your mortgage, it’s getting flooded every single year.”

The group also released analyses of the risks facing Delaware, Maryland and Virginia, and some of the most troubling findings show how climate change will affect military installations, Strauss said.

The “labyrinth of tidewater channels and creeks” in the Norfolk, Virginia, area make the naval base there, the world’s largest, especially vulnerable to climate change, Strauss said. Among the three states, Virginia’s population is most at risk, with 107,000 residents living less than 5 feet above high tide, the researchers said. Maryland has the most property at that level, with more than $19.6 billion at stake.