As the sea level rises, the east coast is also sinking

CLIMATOLOGISTS ALREADY know that the east coast of the United States could see sea level rise by 2050, which in itself will be catastrophic. But they are just beginning to carefully measure the "hidden vulnerability" that will make the situation even worse: the coast will also sinks. It's a phenomenon known as subsidence, and it's poised to make a rising ocean even more dangerous, both for people and coastal ecosystems. New research published in the journal Nature Communications found that the Atlantic coast—home to more than a third of the U.S. population—is sinking by a few millimeters a year. It's up to 5 millimeters (one-fifth of an inch) in Charleston, South Carolina, and the Chesapeake Bay. In some areas of Delaware, that's as much as double. Five millimeters of annual sea-level rise along a stretch of coast, plus 5 millimeters of subsidence there, is effectively 10 millimeters of relative sea-level rise. Cities on the Atlantic coast are already suffering from persistent flooding, and the deluge will only get worse as they sink while seas rise. However, such high-resolution land subsidence data are not yet considered in coastal hazard assessment. "What we want to do here is really bring awareness to this missing component, which, based on our analysis, actually makes the near-term vulnerability much worse than you would expect from sea level rise alone," says Manoochehr Shirzaei, an environmental security expert. at Virginia Tech and co-author of the new paper.  (Wires. Manoochehr Shirzaei)