America's East Coast - Rising Sea, Sinking Land

A young kayaker on Manchester Avenue in Norfolk, Va., in October 2012, when Hurricane Sandy caused flooding. Norfolk is struggling to cope with rising seawater and sinking land. Matthew Eich for The New York Times

The last time I wrote about the rising sea levels impacting America's East Coast a far right commenter left a spittle flecked comment (which I did not publish) ranting that natural forces are at work on the situation facing the East Coast and denying that human activity had any role in the growing problem for cities like Norfolk, Virginia.  For clarity - lest the same anonymous climate change denier revisit this blog - I do NOT deny that some natural forces are at play.  However, man made phenomenon are making the situation worse and accelerating the problems as laid out in these excerpts from a story in the New York Times (NOTE: Here in Virginia, GOP legislators bar the use of the term "rising sea levels" and insist on using the term "areas of repetitive flooding" rather even partially admit that climate change is occurring):

Scientists have spent decades examining all the factors that can influence the rise of the seas, and their research is finally leading to answers. And the more the scientists learn, the more they perceive an enormous risk for the United States.

Much of the population and economy of the country is concentrated on the East Coast, which the accumulating scientific evidence suggests will be a global hot spot for a rising sea level over the coming century.

The detective work has required scientists to grapple with the influence of ancient ice sheets, the meaning of islands that are sinking in the Chesapeake Bay, and even the effect of a giant meteor that slammed into the earth.

The work starts with the tides. Because of their importance to navigation, they have been measured for the better part of two centuries. While the record is not perfect, scientists say it leaves no doubt that the world’s oceans are rising.

The evidence suggests that the sea-level rise has probably accelerated, to about a foot a century, and scientists think it will accelerate still more with the continued emission of large amounts of greenhouse gases into the air. The gases heat the planet and cause land ice to melt into the sea.

The official stance of the world’s climate scientists is that the global sea level could rise as much as three feet by the end of this century, if emissions continue at a rapid pace. But some scientific evidence supports even higher numbers, five feet and beyond in the worst case.

Scientists say the East Coast will be hit harder for many reasons, but among the most important is that even as the seawater rises, the land in this part of the world is sinking. And that goes back to the last ice age, which peaked some 20,000 years ago.

As a massive ice sheet, more than a mile thick, grew over what are now Canada and the northern reaches of the United States, the weight of it depressed the crust of the earth. Areas away from the ice sheet bulged upward in response, as though somebody had stepped on one edge of a balloon, causing the other side to pop up. Now that the ice sheet has melted, the ground that was directly beneath it is rising, and the peripheral bulge is falling.

Some degree of sinking is going on all the way from southern Maine to northern Florida, and it manifests itself as an apparent rising of the sea.

Coastal flooding has already become such a severe problem that Norfolk is spending millions to raise streets and improve drainage. Truly protecting the city could cost as much as $1 billion, money that Norfolk officials say they do not have. Norfolk’s mayor, Paul Fraim, made headlines a couple of years ago by acknowledging that some areas might eventually have to be abandoned.

[A]mong the American public, the impulse toward denial is still strong. But in towns like Norfolk — where neighborhoods are already flooding repeatedly even in the absence of storms, and where some homes have become unsaleable — people are starting to pay attention.

Would that more people were paying attention in both Richmond and Washington, D.C.

AVERAGE SEA LEVEL RISE

measured by tide gauges

1.5 inches or more per decade