Climate Change: The Next Generation: Sea level rises would flood Philly…and NYC and DC and Miami

Sea level rises would flood Philly…and NYC and DC and Miami

by Barbara Kessler, Green Right Now, October 20, 2009

By now you’ve heard the dire predictions for how sea level rise would affect Miami. Basically this city, already imperiled by worsening hurricanes, is in the bulls-eye for rising oceans too.

But did you realize that a one meter sea level increase — now believed by many scientists to be a likely outcome of global warming by 2100 — would put Philadelphia underwater?

Greenland Ice Flow (Photo: NASA)

Yes, the city of Brotherly Love would be among the large family of coastal cities potentially devastated by coastline changes. And not in the too-distance future either.

According to glacier and ice shelf expert Dr. Gordon Hamilton, Philadelphia could experience troubles decades before that 2100 benchmark if storm surges pushed rising oceans inland.

In other words, there is no magic threshold when the seas, warmed by the atmosphere and swelled by melting ice sheets, will spill over their old boundaries. There is a steady creep occurring now. But flooding, hastened by storms, could happen well before the ocean’s reach the 1 meter increase (absent any serious human action to slow the current progression).

Hamilton, a research professor at the University of Maine who studies melting ice sheets in Greenland and Antarctica , and Dr. Asa Rennermalm, a Rutgers University professor who studies Arctic and Greenland ice sheets, are kicking off a lecture tour today to spread this news about how the oceans are rising even faster than projected just a couple years ago.

The first talk was this morning at the Wagner Free Institute in Philadelphia followed by a demonstration at the Adventure Aquarium in Camden, N.J. Subsequent engagements will take the pair to Miami; Washington, New York City and several other cities. The tour, dubbed the “hip boot tour” to emphasize the reality of the coming floods, is sponsored by Clean Air-Cool Planet, a non-profit dedicated to fighting global warming.

None of these cities where the scientists will be speaking will be spared by rising sea levels. Just as most mega-cities around the globe will be affected, because so many population centers sit on the coast or on rivers that lead directly to the coast. Cities like Paris. And Philadelphia.

Talking to Hamilton is a bit like previewing one of those apocalyptic movies where the world suffers from monster storms, vast floods, temperature changes and incredible destruction of infrastructure.

At a one-meter rise, for instance, the subway entrances in Manhattan would be at the water level, which means the subways would be inundated, permanently, said Dr. Hamilton, whose degree is in geophysics.
One doesn’t need a degree in geophysics to understand the consequences of the nation’s financial capital being underwater. Having St. Louis and Chicago on dry ground would not ameliorate the devastation to humans and world trade.

In Philadelphia, a 1 meter increase would flood the downtown district and areas along the river. Harbor trade would be shut down and on the east side, Camden, N.J., would be inundated. Across New Jersey, aquifers would likely be contaminated with sea water.

Neighborhoods at higher elevations, north and west of Philadelphia would remain dry.

Parts of Florida at 33 feet above sea level and below are shown flooded (Image: NASA.)

In Miami, nothing would be unaffected. A one-meter sea level rise would put most of the city underwater, and it wouldn’t be alone. “Most of Florida’s big cities would be severely affected,” Hamilton said. Models overlaid on satellite images show Miami, the Keys, St. Petersburg and Tampa under water. The everglades would become a saltwater marsh and aquifers in the state would become brackish or completely salinated.
Hamilton says he shows people how their city’s coastline would change, but also tries to get local audiences to see the global nature of the problem. “Not only are you flooding downtown DC, but hundreds of millions of people in Southeast Asia like Bangladesh, ” he said.

The key point of the tour is not just to demonstrate impending devastation, but to explain that the threat is more imminent than was predicted by the Interplanetary [a reader notes that this word should be "Intergovernmental"] Panel on Climate Change (IPCC) just two years ago.
In 2007, the IPCC warned that the sea levels would rise a little more than half a meter and possibly more.

Even at that less drastic increase, the “the impacts are virtually certain to be overwhelmingly negative,” scientists wrote.

That prediction was based on the best available science.

What didn’t make the report, Dr. Hamilton said, was that in 2005, geophysicists studying the freshwater ice sheets in Greenland and changes in Antarctica had witnessed an alarming quickening in the speed of some glaciers as they carried ice toward the ocean.

In Greenland, some of these rivers of ice “were doing these crazy things,” he said. Some were moving 45 meters in a day — about the distance of one half a football field. In glacial terms, they were moving very fast. You could hear the ice cracking, he said.

“Almost over night, in the course of 9 to 10 months, they started moving about three times faster than they had been,” Dr. Hamilton said.

Scientists know the changes were prompted by global warming, and that the ice melts can grow exponentially, with water in crevasses contributing to the problem. But they still don’t understand what it all means. Some glaciers later slowed, but others sped up, Hamilton said. The net effect is likely to be a faster melt, with more water raising the ocean levels worldwide.

“Our talks right now are to emphasize that the picture has changed dramatically. If you were to take a consensus among my colleagues who work in Greenland and Antarctica, everybody is likely to say that it (sea rise) is more likely to be a meter.”

If not more.

“Politicians,” he said, “regardless of their political leanings on climate change need to be aware that they’re ethically bound to consider the upper bounds of sea level change…It’s delinquent for people to say they’re going to plan for the minimum (possible change) and then in 50 years time find that huge amounts of their infrastructure is flooded because they didn’t pay attention.”