Environment

The Atlantic Coast Is Sinking

The 5,000 North Carolinians who call Hyde County home live in a region several hundred miles long where coastal residents are coping with severe changes that few other Americans have yet to endure.

Geological changes along the East Coast are causing land to sink along the seaboard. That's exacerbating the flood-inducing effects of sea level rise, which has been occurring faster in the western Atlantic Ocean than elsewhere in recent years. New research using GPS and prehistoric data has shown that nearly the entire coast is affected, from Massachusetts to Florida and parts of Maine with Hyde County subsiding at a little more than an inch per decade.

The study, published this month in Geophysical Research Letters, outlines a hot spot from Delaware and Maryland into northern North Carolina where the effects of groundwater pumping are compounding the sinking effects of natural processes. Problems associated with sea level rise in that hot spot have been — in some places — three times as severe as elsewhere.

On average, climate change is causing seas to rise globally by more than an inch per decade. That rate is increasing as rising levels of greenhouse gases in the atmosphere trap more heat, melting ice and expanding ocean waters. Seas are projected to rise by several feet this century — perhaps twice that much if the collapse of parts of the Antarctic ice sheet worsens.

Ocean circulation changes linked to global warming and other factors have been causing seas to rise much faster than that along the sinking mid-Atlantic coastline — more than 3.5 inches per decade from 2002 to 2014 north of Cape Hatteras in North Carolina, a recent study showed.

Taken together, that suggests the sea has been rising along the county's shorelines recently at a pace greater than 4.5 inches per decade — a globally extraordinary rate. Similar effects are playing out in places that include Sandy Hook in New Jersey and Norfolk in Virginia, the analysis shows.