Air Date: Week of June 29, 2012

The last house on Holland Island, Chesapeake Bay. (Photo: Flickr/CC BaldEagleBluff)

A new survey of American coastal regions shows the hot spots where sea levels are rising fastest. Ben Strauss directs the program on Sea Level Rise at Climate Central, a research and news organization. He tells host Bruce Gellerman that much of the Eastern seaboard will see the most dramatic coastal flooding.

Transcript

GELLERMAN: From the Jennifer and Ted Stanley Studios in Somerville Massachusetts, it’s Living on Earth. I’m Bruce Gellerman. Turns out, when it comes to global warming, and rising sea levels, not all coastlines are created equal. There are coastal hot spots that will suffer significantly more flooding than other places in the future.

That‘s according to a new study by the US Geological Survey. For analysis we turned to Ben Strauss. He directs the program on Sea Level Rise at Climate Central, it's a news and science research organization.

GELLERMAN: So, I thought that when ice on the glaciers melts, that it would disperse the water globally and the water would rise equally.

STRAUSS: Yes, I think that’s the first natural assumption. But the ocean isn’t flat. There are currents moving throughout the ocean and they make its surface slightly uneven - kind of like the surface of a river or stream, it’s not exactly flat. They bulge up where the current is faster, then there are lower pools, where the water is slower.

And melting water from the Greenland ice sheet has the effect of making the ocean a little fresher, a little less salty. And that, in turn, we believe, slows down the Gulf stream. In fact, climate models have been projecting for many years that this would happen. The study that just came out was the first evidence supporting this prediction.

GELLERMAN: And the study looks back over the last 60 years and it says that the sea level rise along this coast is 3-4 times the global average.

STRAUSS: Yeah. What we have here is strong evidence that the rate of sea level rise is accelerating in this hotspot. And, ultimately, it’s fast sea level rise that can hurt us the most, because it doesn’t give us a lot of time to adjust.

GELLERMAN: But what makes the hot spot so hot? What is it about this part of the coast?

STRAUSS: Well, our sea level is a lot lower than the global average and that’s mostly because of the Gulf Stream. And the Gulf Stream normally helps to pull water away from the Northeast coast. When it slows down, it’s almost like water piles up in a traffic jam and gets higher.

GELLERMAN: So, in terms of this part of the north Atlantic coast, Water World is not something in the distant future--it’s happening now and it’s going to accelerate in the very near future.

STRAUSS: Well, that’s certainly the fear. What we’ll really notice is more and more floods, because this change in the average sea level means that coastal storm surge has a higher launch pad. If you raise the floor of a basketball court, you’re going to see a lot more dunks. And the same thing is happening with sea level rise and coastal flooding and that can make a big difference in the damage that they do.

GELLERMAN: So what do people do about this? I mean, city planners…you’ve got roads and you’ve got beaches and you’ve got subways and you’ve got tunnels - what’s somebody to do?

STRAUSS: Yeah, this hot spot… its field arises right around the most densely populated place in the United States! It’s as if someone up there has an unfortunate sense of humor. Our own research at Climate Central shows that over one million people live on land less than five feet above the high tide line in the Northeast corridor. There’s really a tremendous amount of planning that needs to take place now.

New York City, I know, is very concerned. The subway system is quite vulnerable. If the wrong storm comes and pushes water a few inches above a threshold to get into the New York City subway system - the whole system could flood within 40 minutes. So, New York is raising lips around the gratings above subways, Boston is looking at it, Philadelphia is as well…

GELLERMAN: So, what do we do? Do we build dikes, do we build barriers? You know, put buildings on stilts?

STRAUSS: Well, the first thing we can do is cut emissions of heat trapping pollution. That can slow down and reduce the amount of sea level rise. But, unfortunately, a lot is already baked in the cake. So we can try and defend ourselves and our assets by protecting beaches, dunes, marshes, and other soft defenses that are generally most defensive against storm surge.

Where that’s not possible, we can build hard defenses, like walls and dikes. Another strategy is to accommodate - basically by flood-proofing infrastructure or homes, to the extent that that’s possible. For example, elevating them or moving critical pieces of equipment out of the basement or the ground floor. And then there’s long-term planning about where we put things: not building more in harm’s way. Because, ultimately, a lot of places won’t be defensible.

GELLERMAN: Well, Ben Strauss, thanks a lot.

STRAUSS: Thank you, Bruce.

GELLERMAN: Ben Strauss directs the program on Sea Level Rise at Climate Central, To explore sea level rise in your area, visit the interactive map on our web site - LOE.ORG.

 

Links

Climate Central’s research on Surging Seas

Sea Level Rise Accelerating in U.S. Atlantic Coast

California Sea Level Projected to Rise at Higher Rate Than Global Average