Why sea level in the D.C. region is rising faster than anywhere else on the East Coast.

Sea level in the Washington, D.C., region is rising fast — faster than any other region along the East Coast. Scientists have now confirmed that this is because, in addition to global warming pushing water levels higher and higher, the ground is literally sinking beneath our feet, and it will probably drop another six inches by the end of the century.

Even without the sinking action, sea level would still be rising because of global warming — melting glaciers (Alaska, Greenland, the West Antarctic ice sheet, to name a few), and thermal expansion (when water warms, it expands). Looking at climate change influences alone, average global sea level is likely to rise anywhere from one foot to to 2.5 feet by 2100.

Combine the two effects — sinking and climate change — and the Chesapeake Bay’s sea level rise could surpass three feet by the end of the century. Of course, that is assuming the absence of a catastrophic melting event in Greenland or Antarctica.

A team of researchers led by the University of Vermont and the U.S. Geological Survey came to this sobering conclusion after an extensive field study where they drilled 70 boreholes, many over 100 feet deep, into the ground around the Chesapeake Bay in the Blackwater National Wildlife Refuge in Dorchester County. Using the depth of the different sediment layers in the boreholes, they were able to paint a portrait the Chesapeake Bay across time and space that dates back millions of years.

They confirmed that the “sinking” at hand is a remnant of the last ice age when a vast sheet of ice covered much of North America, as far south as the Ohio Valley and New York City. That glacier was heavy, causing the ground to sink beneath its weight. As a result, the areas bordering the ice — like Washington, D.C. — bulged upward. “It’s a bit like sitting on one side of a water bed filled with very thick honey,” lead author Ben DeJong explains.

In the thousands of years since the massive glacier retreated, the areas that were under ice have risen and the bulge has sank, but it’s far from finished. It’s a process that will continue for tens of thousands of years, and the D.C. region is locked in to the half-foot of sea level rise that comes with it, in addition to the rising tides from climate change.

What does this mean for the D.C. region? Given the results of the study, sea level will likely continue to rise faster in this region than anywhere else on the East Coast, and the authors strongly advise that preparations be made now for the additional water from the sinking motion. “Six extra inches of water really matters in this part of the world,” said DeLong.

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2015/07/29/why-sea-level-in-the-d-c-region-is-rising-faster-than-anywhere-else-on-the-east-coast/?postshare=6581438189729560