Waterfront cities face a 'floodier future,' spurred by rising seas

Water floods Van Brunt Street in the Red Hook neighborhood of the Brooklyn borough of New York on Oct. 30, 2012.


By BRIAN K. SULLIVAN | Bloomberg | Published: July 10, 2019

Buying a house on the water? By the time your 30-year mortgage expires, you could be facing between 25 and 135 days of high-tide flooding, depending on where you live.

That's the message from the National Oceanic and Atmospheric Administration in a report that says rising seas spurred by climate change will put waterfront U.S. cities at risk for 25 to 75 days of high-tide flooding by 2050. There were 10 days last year on average in the Northeast, with the city of Washington having 22 days, the study released Wednesday said.

Some regions, meanwhile, will see even greater increases, according to William Sweet, a NOAA oceanographer and the report's lead author. High-tide flooding, also called "sunny day flooding," occurs even without storms, largely driven by rising ocean levels, he said.

"The New York City region, which had about 12 days of high-tide flooding in 2018, will experience somewhere between 55 to 135 days" on average in 2050, Sweet said on a conference call with reporters. "The current trajectory suggests, let's say, a floodier future."

About two-thirds of sea level rise is caused by land-based ice melting away, and the rest from rising oceans expanding as they get warmer, according to the report. "Flooding that decades ago usually happened only during a powerful or localized storm can now happen when a steady breeze or a change in coastal current overlaps with a high tide," it read.

The number of high-tide flooding days has doubled since 2000, according to the agency. "The future is already here in terms of sea level rise impacts," Sweet said.

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