There’s going to be a lot more flooding in New York this year as climate change causes sea levels to continue to rise. The Battery, at the southern tip of Manhattan, flooded 10 times in the 12 months through April, according to the National Oceanic and Atmospheric Administration’s annual report. In the year-long period that began in May, the agency expects it happen as many as 14 more times. That’s a big change from the early 2000s, when the Battery would flood less than 5 times per year.
Along the East Coast and Gulf of Mexico, sea levels reached all-time highs, with Chesapeake Bay, Annapolis, Maryland, and Virginia Key near Miami among areas that saw record surge.
Often, high-tide flooding occurs when there’s a nearby storm. But in these cases, called “sunny day flooding,” tides rose at least 1.6 feet (0.5 meters) or more above average high-tide levels because global warming is causing water to expand and glaciers to melt. Along the U.S. coastline, the ocean rose to a record 1.1 foot on average, above 1920 levels.
“Flooding that only happened with a storm is happening all the time,” Nicole LeBoeuf, acting director of NOAA’s ocean service, said in a call with reporters. The global rate of sea-level rise has been about an inch every 8 years.
More is coming, according to the agency. By 2030, the Battery will flood 20 to 40 times a year and by 2100 that could rise to 50 to 135 times, the report said. The current record at the tip of Manhattan is 15, set in 2017.
While human-caused climate change is a big factor, other activities by people have made the situation worse, such as in Norfolk, Virginia, where pumping groundwater for drinking has caused the land to sink. “This is the new normal in a floodier future,” said William Sweet, an oceanographer with NOAA.