Expert Explains Possible Effect of Rise in Sea Levels Michael Oppenheimer, professor of geosciences and international affairs at Princeton University, talks with Melissa Block about the potential effects of a rise in sea level.

Expert Explains Possible Effect of Rise in Sea Levels

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What might an ice melt of this magnitude actually look like? To help answer that question we turned to Michael Oppenheimer. He is a professor of geosciences and international affairs at Princeton, and he studies the potential effects of global warming. Professor Oppenheimer, thanks for being with us.

Professor MICHAEL OPPENHEIMER (Geosciences and international affairs, Princeton University): Happy to be here.

BLOCK: If this is true, if the oceans are going to be rising between 13 and 20 feet, help us understand what the coastline of, say, North America would look like.

Professor OPPENHEIMER: Well, take a look at your pinkie and take a look at your thumb. If your thumb is the Florida peninsula today, and if you look at your pinkie and you knock off the end joint, that's what Florida would look like in the future if this sort of sea level rise occurred. It would remake and largely destroy the coastal zone as we know it.

BLOCK: That dramatic?

Professor OPPENHEIMER: That dramatic. And if you look at the Gulf Coast, the effects are even more extensive. You have to remember that it's really two ice sheets that are at issue here, Greenland and West Antarctica, and there's a potential eventually that both of them could disintegrate into the ocean. If that happened, the Gulf Coast would move up to Houston, and the Gulf Coast in Louisiana would move up to almost Baton Rouge. So we're talking about a monumental reconfiguration of the continent.

BLOCK: And what about the West Coast?

Professor OPPENHEIMER: The West Coast is a bit different, because some of the coastline is covered by bluffs which come right down to the sea. But if you look at an area like San Francisco Bay, the Los Angeles basin, 20 feet of sea level rise would go way into both of those basins and have a very substantial effect in drowning large parts of what are now urban areas.

BLOCK: And if you were living inland, maybe St. Louis, Missouri, say.

Professor OPPENHEIMER: In a direct way, it wouldn't affect the inland area, because if you go far enough inland you get hundreds and eventually thousands of feet above sea level. But a huge fraction of the population and the infrastructure and the economic value of the world is conducted in what is now the coastal zone.

For instance, you know, we're arguing about the investment in protecting U.S. ports. Well, all existing port facilities would be destroyed except high bridges. All of the farming in heavily populated deltas like Bangladesh would be gone. Where would those people go? For instance, in that particular delta, right now there are about 120 million people. So we're talking about remaking major areas of the world.

A simulation was run with policy experts from the Netherlands and from the U.K. over the last couple of years, asking them what would you do if there were a 20-foot sea level rise? Would you act to protect London, which would require a much bigger barrier than it now has? The answer was, if it happened fast enough, they would abandon London. They would abandon Amsterdam.

Now, if it happened slowly, and by slowly I mean of the order of say a thousand years or more, then I think human beings would be able to adjust. If it happened fast, and I'm talking about a few hundred years, then I think the possibilities for adjustment are very, very limited, and the whole thing really would be classified as a catastrophe.

BLOCK: Well, when you talk about adjusting, how would we adjust over that period of time?

Professor OPPENHEIMER: If it happened gradually, and we saw it coming, we would undoubtedly provide incentives for people to start moving away from the coast, for infrastructure in cities to start building more in the back areas, so to speak, and basically gradually abandoning habitation. Now, that sounds all rational and sensible, but the trouble is a lot of what we value very highly is right there in the coastal zone. If you go to Venice, see St. Mark's Cathedral, go to Washington, D.C. and visit the Mall, or, you know, the area up to Capitol Hill. And much of that is simply going to be gone. So we're talking not just about economic value, we're talking about high cultural value as well.

BLOCK: Professor Oppenheimer, thanks very much.

Professor OPPENHEIMER: You're very welcome.

BLOCK: Michael Oppenheimer is professor of geosciences and international affairs at Princeton.

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