Sea Level Rise Could Flood NYC, Miami: NOAA

A new government report released on Tuesday says sea levels along U.S. coastlines could rise 10 to 12 inches in the next 30 years, with cities like Miami and New York seeing regularly-occurring, costly floods, even on sunny days.

The report, which was released by the National Oceanic and Atmospheric Administration, is particularly alarming given that, in the 20th century, they state that seas along the Atlantic coast rose at the fastest clip in 2,000 years.

The rate of sea level rise has more than doubled from 0.06 inches (1.4 millimeters) per year throughout most of the twentieth century to 0.14 inches (3.6 millimeters) per year from 2006–2015.

“Make no mistake: Sea level rise is upon us,” said Nicole LeBoeuf, director of NOAA’s National Ocean Service.

LeBoeuf warned that the cost will be high, with much of the American economy and 40% of the population situated along the coastlines. The worst of the long-term sea level rise from the melting of ice sheets in Antarctica and Greenland, though, likely won’t kick in until after 2100, said ocean service oceanographer William Sweet, the report’s lead author.

Warmer water expands, and the melting ice sheets and glaciers add more water to the world’s oceans.

Sea level rise report a “red flag”

The report “is the equivalent of NOAA sending a red flag up” about the accelerating rise in sea levels, said University of Wisconsin-Madison geoscientist Andrea Dutton, a specialist in sea level rise who wasn’t part of the federal report. The coastal flooding the U.S. is seeing now “will get taken to a whole new level in just a couple of decades.

“We can see this freight train coming from more than a mile away,” Dutton said in an interview with The Associated Press. “The question is whether we continue to let houses slide into the ocean.”

Sea levels rise more in some places than others because of sinking land, currents and water from ice melt. The U.S. will experience slightly more sea level rise than the global average. And the greatest rise in the U.S. will be on the Gulf and East Coasts, while the West Coast and Hawaii will be hit less than average, Sweet said.

Between now and 2060, expect almost 25 inches of sea level rise in Galveston, Texas, and just under two feet in St. Petersburg, Florida, while only 9 inches will occur in Seattle and 14 inches in Los Angeles, the report said.

Sea level rise to trigger “moderate” floods, replacing “nuisance” floods

While higher seas cause much more damage when storms like hurricanes hit the coast, they are becoming a problem even on sunny days.

Cities, such as Annapolis, Maryland, and Miami Beach, Florida, already experience a few minor “nuisance” floods a year during high tides, but those will be replaced by several “moderate” floods a year by mid-century.

“It’s going to be areas that haven’t been flooding that are starting to flood,” Sweet said. “Many of our major metropolitan areas on the East Coast are going to be increasingly at risk.”

And that’s just until 2050. The report is projecting an average of about 2 feet of sea level rise in the United States — more in the East, less in the West — by the end of the century.