MS. LAURA KNOYThanks for joining us. I'm Laura Knoy with New Hampshire Public Radio sitting in for Diane Rehm. She's on vacation. August is a popular month for Americans to head to the beach, but many shorelines face threats from rising sea levels, storms and erosion and so the sea walls to protect coastal buildings may be built higher. In fact, some predict these protective barriers could become so tall that we won't be able to see the ocean.

MS. LAURA KNOYWith me in the studio to talk about beaches, Rob Moore with the Natural Resources Defense Council. Also, from a studio in North Carolina, Orrin Pilkey with Duke University and by phone from Baltimore, Joe Vietri with the U.S. Army Corp of Engineers. And welcome to all of you. Thank you for being here.

MR. ROB MOOREThanks for having us.

DR. ORRIN PILKEYThanks.

MR. JOSEPH VIETRIThanks for having us.

KNOYAnd let's hear from you, too. 1-800-433-8850. 1-800-433-8850. Email is drshow@wamu.org. You can find us on Facebook or Twitter. And Orrin Pilkey, I did want to start with you. Professor emeritus of geology at Duke, you've been writing and studying about beaches for decades. What are you seeing, Orrin, about the threats to shorelines today.

PILKEYWell, to start with, about 90 percent of the world's open ocean shorelines are eroding, some very slightly and some at a very rapid rate. And with time, more and more beachfront houses or buildings of various kinds are being threatened. This is for two reasons. One is because more people are moving to the beach and secondly, the erosion is catching up with some of the older buildings and increasingly communities and states are choosing to hold the shoreline in place against the rising sea and the storms and so forth.

PILKEYAnd there are two ways, basically two ways by which this is done. One is construction of sea walls and the other is replenishing the beach, which means bringing in new sand.

KNOYYeah, and you write so eloquently, Orrin, about this idea of manmade structures trying to, as you just said, hold the shoreline in place, but shorelines can't be held in place. They're natural. They're evolving. They're always coming and going. Give us a sense of how the natural cycle of a shoreline is a very dynamic thing.

PILKEYYeah, it is a very dynamic thing. Shorelines move back and forth with storms and various other -- for various other reasons. The, I think, you know, for a shoreline -- a natural shoreline has no problem. Moving back is not a problem. Nobody cares. There are a lot of shorelines moving back on our national seashore. People don't even know they're moving back. But once you put building in the way, it, of course, becomes a vastly different problem.

PILKEYAnd the big problem with sea walls, sea walls are the worst thing you can put on a beach. If a beach is eroding, putting in a sea wall will cause the loss of the beach. It might take a few years. It might take a few decades, but that beach is going, will be gone, because you put a sea wall in place.

KNOYWell, and Rob, to bring you into it, what's the key problem, as you see it with our beaches and their health right now and in the future?

MOOREWell, I think Dr. Pilkey's book, which I had the pleasure of reading myself just a couple weeks ago, really spells out what some of the risks are to our beaches at present. You know, to me, what is even more troubling is the fact that, because of climate change, we're going to be seeing an acceleration of those problems and an exponential increase in the difficulty of managing our coastal areas. You know, scientists are now projecting anywhere on the -- what almost could be considered the conservative side these days of 2 to 4 feet of sea level rise by the end of the century.

MOOREMost of those types of projections, however, don't factor in the accelerating rate of melting of the polar regions that scientists believe they are seeing over the last decade. So once you start factoring that in, it becomes an exercise in managing climate change in how do we limit the most severe impacts that we are likely to experience?

KNOYWell, it's interesting to hear Orrin say that sea walls are the worst thing you can do to a beach. I grew up on the North Shore, Massachusetts and there was the beach and there's the humble sea wall and it just -- that's how it was. You know, we always thought there were more threats to beaches like pollution and garbage and, you know, who knows what, but the sea wall was just something there. It protected the houses and that's the way it was.

MOOREYeah, and it's measures like sea walls and other types of constructed interventions that we've used that have encouraged people to not only move to the beach, but also stay at the beach. You know, about 39 percent of the U.S. population lives in coastal counties. And just this...

KNOY39 percent?

MOOREThat's correct.

KNOYThat's a lot.

MOOREIt's a lot. And just since 1970, we've seen about 35 million people move closer to the beach and move into those coastal areas. And when you think about 4 feet of sea level rise, you know, there's studies that have been done that show that we're looking at about 5 million people, about 2.5 million households that will be inundated with 4 feet of sea level rise. And that's not taking into account any, you know, storm surges or tropical storms that would push waves further inland from that.

KNOYWell, a little bit later, I hope to talk with all of you about what we've learned from Hurricane Sandy and Katrina and some of these other big storms. But to bring you into this, too, Joe Vietri, with the Army Corps of Engineers, how does the Army Corps of Engineers see this? What are the threats to coastal areas that concern you the most?

VIETRIWell, you know, first off, I could not agree more with my colleagues' description of what we currently face and what we're currently dealing with. You know, we are looking at a heavily developed coastal regions. We have found, as our work as a result of Hurricane Sandy, that the populations have increased. They've gotten older. And in some case, when you get these urban settings, such as New York City, the populations at risk tend to be, in some cases, like with Coney Island and Long Beach, excuse me, and in Rockaway, they tend to be of lower income.

VIETRISo their ability to make decisions and move is somewhat hampered by their financial ability. As you look across, you know, the landscape of the North Atlantic, certainly during Hurricane Sandy, roughly 31,000 miles of tidally influence coastline was affected. That's a staggering amount of land. I know we're focusing on the beaches, but the areas behind those beaches, the oceanfront beaches, which is the backside of the estuaries, the abutting ravine systems that join those estuaries, et cetera, all face these same exact risks.

VIETRIAnd one of the things that we have been challenged with and certainly it started after Hurricane Katrina, is to look at these systems -- and I use the word system -- and look at them in their totality and not just look at the beach and what's currently going on in the beach. There's some discussion about, you know, sea walls, beach restoration, break waters. Those are all, in my mind, they're tools or solutions to address the problem. And the problem is, as Dr. Pilkey points out, is global.

VIETRIIt will continue to get worse and it's causing a lot of soul-searching on the part of local communities and governments in how they're going to deal with this risk. And one of the key components to this and let's just get it on the table right away is the fact of land use. And land use really is a locally controlled factor in the United States and that has a lot to do with the building trends that we're seeing, the type of buildings that you see going in as well as the type of activities that are being permitted within those vulnerable coastal areas.

KNOYRight. So federal officials can say whatever they want, but at some level, you're saying, Joe, it's a local decision.

VIETRIIt is a local decision on how land use and the land use patterns are developed. Now, the federal government and state governments can do certain things and certainly reward good behavior and penalize bad behavior and to a great extent, they do that. But overall, when you have this clash of population density and you have this diminishing resource, which is these natural features, I mean, if you think about it, on Long Island, for example in the western ends of it, we have probably close to over 250 to 300,000 people living on basically barrier islands or peninsulas that are 10 feet above sea level.

VIETRIThat's today as we know it. Now, imagine now if you added some of the numbers that we were just talking about, anywhere from, let's say, you know, 12 inches to 6 feet of potential sea level change. We really are facing a real serious problem in a lot of these coastal communities.

KNOYSo that's the struggle then, all of you, right? Orrin Pilkey, I'll turn to you first. Short term, we've got these folks living along the ocean. What do you do with them? How do you protect their house? How do you protect them? But long term, as you all are saying, this overdevelopment by the coastal area is harming the beach and harming the coastal area itself. So how do you resolve that struggle, Orrin?

PILKEYWell, I guess the way I look at it is that we have a choice between buildings and beaches. We can have buildings and we can have beaches, you know, buildings right on the beach or we can have the beaches, but we can't have them both. And we've got to face that. Already, some -- we're looking at this globally. Already some societies are already threatened to the point where they have to move, such as in native Alaskans and native Siberians, which amount to several thousand.

PILKEYAnd there's about a million (word?) dwellers in the Indian and Atlantic Ocean. They are already starting to move and then there's probably 100 million or more people living on deltas, such as the Mississippi or more important, the Ganges, Brahmaputra and some of the -- Nile and the Niger delta, all these places are really eroding fast. They're sinking as a rule and those people are already -- those -- you're dealing with millions there. We're dealing with millions. And those people are already on -- getting ready or are already starting to move.

KNOYSo this is already happening, Orrin?

PILKEYIt's already happening.

KNOYPeople are retreating from the beach.

PILKEYAnd we should be also planning on this. We can either respond to this erosion problem, waiting until catastrophes occur, like Hurricane Sandy, or we can plan and respond in a planned fashion and start to respond now by various means. Primarily, we argue, we're going to have to -- not talking about urban, but on non urban shorelines, we're going to have to move back. We don't have any choice in the long run.

KNOYAll right. And let me remind everyone, coming up, we'll talk more about beaches and the balance with coastal development and we'll take your questions and comments. Stay with us.

KNOYWelcome back. I'm Laura Knoy, sitting in for Diane Rehm. We're talking this hour about our beaches and the impact of coastal development. Our guests for the hour are Rob Moore, senior policy analyst for the Natural Resources Defense Council. Joining us from North Carolina, Orrin Pilkey, a professor emeritus of geology at Duke University, co-author of the recent book "The Last Beach." And joining us from Baltimore, Joe Vietri, director of the National Planning Center For Coastal & Storm Risk Management at the U.S. Army Corps of Engineers.

KNOYYou can join us, too, with your questions, comments, concerns about our beaches, especially if you live by the coast, 1-800-433-8850, 1-800-433-8850, drshow@wamu.org is the email. Find us on Facebook or Twitter. And before we go to our listeners, Rob Moore, I was struck by Orrin Pilkey said just before the break. You can have buildings, you can have the beach but not both. And he cited a couple examples of places in the world where people are already retreating from the shoreline, it's just gotten too dangerous.

MOOREYeah, and in those examples, I think, you're seeing people that are retreating from shorelines out of necessity. It's not because they recognize the future threat they face and are making a deliberate and conscious and logical decision to -- golly, I'd be a lot better off if I lived on higher ground. They're retreating because they simply -- the land isn't there anymore. It's become untenable to live in those places.

MOOREWe have the luxury here in this nation of having the knowledge and the foresight to actually do things a little bit more deliberately. We don't have to just simply trip our way from catastrophe to catastrophe, reacting along the way. We could make a much more deliberate effort to encourage people to relocate out of areas that are susceptible to floods and are vulnerable to future sea level rise and start to move things out.

MOOREYou know, one of the things that our guest from the Corps mentioned is that local land use -- local governments are responsible for making land use decisions and in many ways have encouraged coastal development, but state and local government, state and federal government, have played a very critical role in encouraging and enabling that dangerous development.

MOORESo the federal government provides taxpayer-subsidized, low-cost flood insurance that allows people to live in areas that are at risk from flooding and tropical storms and coastal erosion, to move in, and they cover their losses and allow them to continue to rebuild after a storm. We build -- we spend billions of dollars in this country on spending -- on building water treatment plants, roads, bridges, all the infrastructure that's necessary for people to live in the coastal areas. These are all things that I think there's a dawning awareness in Congress and certainly from this administration that we need to do business a lot differently.

MOOREThe federal government shouldn't be in the business of incentivizing people to live in areas that we may be trying to move them out of within our lifetime and certainly within our children's and grandchildren's lifetimes.

KNOYWow, and flood insurance, a huge issue, and every time there's a major storm, this comes up. And people ask that question, you know, why should the government subsidize the insurance of folks who live in these vulnerable areas. What do you think, Joe Vietri?

VIETRIWell, I can't really speak to the national flood insurance program in depth, but what I can tell you, though, it's somewhat of a misnomer to say that the flood insurance program is making people whole. In fact, if anything, during Hurricane Sandy, we saw that to be the exact opposite. In many of these locations, in the case of Long Island on the South Shore, for example, you have 27,000 homes in the 100-year flood plain as we know it today. Obviously, that number will quadruple well into the future.

VIETRIAnd what we see here, though, is regular people, people who go to work every day. They're certainly not wealthy people. But in many cases some of these folks, because they're elderly, their mortgages are paid off, they chose not to even participate in the national flood insurance program, and they are still trying to recover to this day, almost two and a half years later, after Hurricane Sandy.

VIETRIYou know, the numbers there just don't bear out. If you're looking at $257,000, I think, which is the maximum that the flood insurance program can pay out, and you look at some of the losses here, you know, during Hurricane Sandy to some of these homes that were nowhere near the ocean, they were in some cases miles inland, and they were still devastated by the storm's effect.

VIETRII will say, though, that certainly, like any program that is administrated, there are certain things that could be done to probably make it better, and I'll leave that to the professionals who are working on that as we're talking today. But I can say that it has basically been the insurer of last resort for many folks, who have lived here or who have bought in these coastal regions, nowhere near the ocean, but probably, you know, in many cases pretty far inland because of the way that the coastal plan and the elevation of the coastal plan is set up.

VIETRISo yeah, there has to be some sort of concerted effort to look at these programs and see what the effects of them are, if they are acting as enablers, but I would suggest to you that when you're dealing with the population density, certainly in some of our bigger cities, whether it be Baltimore, Washington, New York, Philadelphia, Miami, Fort Lauderdale, and I could go on and on and on with a list along, just along the East Coast, I mean, certainly the fact that you're going to say that we might just pick up all of those folks and move them immediately is certainly not really realistic.

VIETRII will say to you, though, that one of the blessings and the curses with sea level rise is the fact that we do have this time horizon to make some changes. But that also is the curse of the program or a curse of the sea level rise numbers, because people are not driven to action, as in the cases that Dr. Pilkey mentioned before.

KNOYUnless there's a dramatic event like a Hurricane Sandy.

VIETRIYes.

KNOYYou know, I want to bring Orrin Pilkey into this. Orrin, picking up on what Joe said, you know, there are so many people, and Rob gave a number, 39 percent, I think it was, you said, Rob, lived in coastal areas. So I hear your concern about the beaches, Orrin, and the buildings along the beach. But what do you do with the folks that live right along the shore? You can't just ask, you know, hundreds of millions of people to pick up and move.

PILKEYWell, yeah, the worst-case scenario in the United States is the Florida shoreline. Both sides of Florida have virtually hundreds of miles of high-rise-lined shoreline. You can't move back high-rises because there's no place to move them in Florida, basically. And so my thinking there is they're not going to move until the buildings fall down or something like that.

PILKEYI see increasing amounts of sea walls. I see sea walls getting very high on both sides of the islands in Florida. And then eventually I just don't see a solution to a high-rise-lined shoreline unless perhaps we're looking at an offshore reef of some kind, or perhaps we're looking at letting these cities and towns flood and then using boats or something to get around. But it's an impossible situation, it seems to me. Florida is in really, really long-term danger, I think.

KNOYSo, and Orrin, sea walls so high that at some point, you're protecting the coastal community, but at some point if you're walking down the sidewalk, you can't see the ocean.

PILKEYThat's right. Well, Sea Bright, New Jersey, which didn't have high-rises, I don't think it still does have high-rises, but it -- I was fascinated by that. That's the -- that's when I really got into this, when I visited Sea Bright, New Jersey. And there was -- you couldn't see the ocean from the second-story windows behind it, and I was fascinated that also the beach was private, and even though you could stand on top of the sea wall, and you could see some of the skyscrapers in Manhattan, it was still a private beach at that time. Things have advanced since then.

PILKEYBut we really -- I think the first thing we should do, right now, right this minute, is prohibit any further high-rise construction on any island or any beach in the U.S.

KNOYAll right.

PILKEYThat would be a major step forward, I think.

KNOYLet's go to our listeners, and as we talk about Florida and some of the challenges there that you mentioned, Orrin, Paul joins us from Orange Park, Florida. Hi Paul, you're on the Diane Rehm Show. Thanks for joining us.

PAULGood morning, excellent topic. Yes, you hit the nail on the head. Florida has more low-lying land, beaches and along the St. John's River, as well. I would estimate there's at least one to two million people living in the flood plain, and we need to be, you know, pulling out all the stops and trying to convince these people to move now rather than wait and have taxpayers, you know, make them good after the sea rise happens, or, you know, if a major storm comes and, you know, does a lot of damage.

KNOYHow do we convince them to move, though, Paul? I mean, it's tough to sell your house even if you want to move, and maybe you don't want to.

PAULYeah, I don't care about what they want.

MOOREActually, this is something NRDC has been working on. I've actually been - we published a paper in April, and we've been talking to members of Congress about an idea to actually do just that, through the national flood insurance program. One of the big debates about flood insurance is how do you provide affordable coverage, especially to low-income people that can't afford to be without the coverage but also can't afford to pay a risk-based rate.

PILKEYOne approach, if I...

MOOREWe put a proposal out that would actually enable people to maintain affordable flood insurance and receive discounts on that federal flood insurance, but in return, the property owner would make a commitment to accept a buyout once their home is heavily damaged by future flooding. It enables them to stay there in the short term, but when it gets to the point of having to pour more money into protecting the property or elevating the property against future floods, a decision is consciously made to allow that person to guarantee them the assistance to relocate to higher ground.

KNOYSo you stay there while you still can, you pay lower rates on your flood insurance, but when your property goes in the next super-storm, you say yeah, I'm not going to rebuild, and I promise to move. That's the sort of bargain there.

MOORERight.

KNOYOrrin, I can hear you wanting to jump in. Go ahead.

PILKEYYeah, well, I find what he says is very fascinating. In fact, I totally agree with that approach. We tried that in both North and South Carolina, where we would not allow buildings destroyed by hurricanes to be rebuilt. After Hurricane -- whichever it was in 1989, a lot of buildings were destroyed, but there was so much pressure from very wealthy people that they gave up on that, and in fact they said the way they did it, they said, well, if you can find your roof somewhere, you can rebuild the building. So it didn't work, but it could work if made differently, if done differently.

KNOYGo ahead, Joe, yeah.

VIETRIYeah, if I may. I mean, most states have prohibitions in place. New York has the Coastal Erosion Hazard Area Act, which says if 50 percent of your building is destroyed, you cannot rebuild. But in effect what happens is the delegation of a lot of these programs is moved down to lower forms of government. The technical expertise in those levels of government is somewhat limited, and they are often challenged in court, and more often than not they tend to lose.

VIETRIAnd so that is a chronic problem. I think the whole concept is one of living with water. And so when we look at, you know, we're offering two extremes here. We're offering building walls, and we're offering basically abandoning the shoreline. And I would suggest to you there's probably something someplace in the middle of that. And it's not the same everywhere, and that's a key statement that we have to make. The situation in Florida or the Outer Banks of North Carolina is not the same as in Lower Manhattan or in Hoboken, New Jersey, and so we have to craft our solution sets with the areas that we are currently looking at both as a community-based...

KNOYSo that's intriguing, Joe. Yeah, so, you know, it isn't as stark as building higher and higher sea walls to protect coastal communities or telling everybody to pack it up and, you know, move five miles inland.

VIETRIAbsolutely not.

KNOYSo what do some of those middle-ground solutions look like, Joe?

VIETRIWell, I'll be honest with you, I think right now the whole notion of this evolution or movement towards a manageable retreat makes a lot of sense. And in doing that, you can look at non-structural solutions. You can look at learning to live with water. In other words, you've got two choices, let the water come in, or try and keep the water out. And so what we're thinking about and what we're looking at in a lot of places around the country now is letting the water in, basically getting houses where we don't have high-rises, for example, or even if we do, moving some of the infrastructure above the lower floors, in homes elevating those homes above the base flood.

VIETRIIn fact, the administration just recently passed that any place that federal moneys are used has to be base flood elevation plus three. So we are taking steps to doing that. You can elevate houses. You can elevate that vulnerable infrastructure in a lot of places. And it's certainly what's going on right now in Lower Manhattan and a lot of the boroughs in New York City. That's number one.

VIETRINumber two, you can make use of more natural defenses, the usage of salt marsh, the usage of wetlands. So basically natural, nature-based features, non-structural alternatives. And then you work through this process where the structural measure of last resort. You know, in a perfect world, you'd like to have people leave, but if you can't, you implement these other solutions that are system-based, and then you basically make a decision tree that says, okay, structural is the last item of resort. And that is only viable as long as the economics hold themselves together.

VIETRIOnce the cost becomes so great, and then the benefits become so low, then in fact you end up in that end state, where you have to actually move. And there are ways to do this, and we have been pretty effective recently in a lot of places from Louisiana to New York.

KNOYAll right, I'm Laura Knoy, and you're listening to the Diane Rehm Show. If you'd like to join us, call 1-800-433-8850, send an email to drshow@wamu.org, follow us on Facebook or send us a tweet. And here's an email from Russ in Darlington, Maryland. He says, has the use of hydroelectric and flood control dams over the past century reduced the available sediment to naturally build beaches, exasperating the problems associated with sea level and coastal development? Russ, thank you so much for the email because Orrin, you talk about this in your book, the sort of upstream impacts that we're seeing on our beaches.

PILKEYYes, that's quite true, especially along the Pacific coast, on the western side of North and South America, for example. But on the East Coast, especially along the barrier island shorelines, the dams really aren't creating a problem because the sand coming down the rivers is usually deposited in the upper parts of the estuaries, and it never quite makes it to the shoreline, to the beaches. So that's not really having a big impact on the East Coast.

PILKEYI would like to say, in response to our friend from the Corps of Engineers here, that the -- although he speaks of the hard structure as being a final solution, if everything else failed, but the way it was working right now, in my view, the hard structure is the way to go. We can see what's happening in Florida now, more and more sea walls. All you have to do is basically declare an emergency, and you can build a sea wall. And I think -- that's the problem.

PILKEYThat's out point in the book, is that globally, sea walls or hard structures of various kind are stepping in. They are the solution, and that's why the beaches will be lost. And I think it's also important to differentiate between the urban solutions and solutions along touristic, along beaches, small communities along beaches. That's quite a different, a different thing. Hard structures are going to have to be used to protect some of our cities, of course.

MOOREThere are a couple things I would actually point out as successful models that kind of mirror -- that kind of illustrate this middle that Joe was talking about and the dynamic that Dr. Pilkey's talking about. In the 1980s, Congress, when it still did things creatively and proactively, passed the Coastal Barriers Resources Act, and it's a very simple law that designated specific stretches of the East Coast, Gulf Coast and even the coasts of the Great Lakes as barrier resources where federal investments would be prohibited.

MOOREYou can't buy flood insurance. The federal government will not invest in infrastructure that allows development to take place. And it's had an amazing effect at preserving barrier islands and beach and coastal resources and prohibiting development. It's not -- I shouldn't say it prohibits development. It does not prohibit development. It prohibits the federal government from spending money that would enable the development, and you've seen development not take hold in those areas.

KNOYComing up, your questions and comments on the future of beaches, and we'll talk more with our guests. We'll be right back. Stay with us.

KNOYWelcome back. I'm Laura Knoy sitting in for Diane Rehm. We're talking this hour about the threats to our beaches and coastal communities. Our guests are Rob Moore, senior policy analyst for the Natural Resources Defense Council. Joining us from North Carolina, Orrin Pilkey, a professor emeritus of geology at Duke University. He's co-author of the recent book, "The Last Beach." And joining us by phone from Baltimore, Joe Vietri, director of the National Planning Center for Coastal and Storm Risk Management at the U.S. Army Corps of Engineers.

KNOYYou can join us, too. The number is 1-800-433-8850. Email is drshow@wamu.org. A couple of emails I'd like to share with you. This is one from Jill in Peterborough, N.H. It relates to something you said earlier, Rob. "Please comment on the Cape Cod National Seashore, where protection of the wild coastline from development has left in place a dynamic coastline, ever changing, but always sustained beaches, contrast Chatham, at the elbow of the Cape, where erosion regularly takes out houses built right along the coast. But sandbars offshore rebuild and move constantly."

KNOYJill, thanks for the email. And you talked about that earlier, Rob. I guess the question then is that's great for those areas that already designated, you know, open and natural seashores, but what about the places that people live, people have businesses and homes? Can you make that switch?

MOOREWell, again, a lot of it is -- comes down to something that Joe said earlier, and I think we've talked -- we already touched on. Local governments make land use decisions, but those decisions are often enabled by funding from the federal government. You know, one of the smartest things the country could do is to stop using taxpayer dollars to facilitate development in risky areas. This is something that the Obama administration is actually looking at.

MOOREThey, through executive order in January, adopted a new set of federal flood protection standards that would apply both to -- both along rivers and coastal areas. And it would basically require federal agencies to really assess the current and future risks of flooding attributable to climate change and sea level rise. And make sure that those investments are spent in a way that we are taking that enhanced risk into account. And hopefully, that would have the effect of either encouraging federal agencies when they build things or give money to state and local governments to build things, to move those things further back.

KNOYHere's an email from Blair, in Chapel Hill, N.C. And one of you mentioned the Outer Banks of North Carolina. He says, "Please ask Orrin about North Carolina's law passed last year that blocks considering climate change when judging development plans." And Blair says, "Orrin will know precisely what I'm referring to." Go ahead, Orrin.

PILKEYWell, that's exactly what's happened. It's -- and in some state agencies the employees have been urged not to use the term sea level rise or global climate change in their writing. And we're not the only state, although I think we may lead the way in this foolishness of ignoring seal level rise. Ironically, the Outer Banks of North Carolina are among the most vulnerable parts of the East Coast shoreline. And we, of all people, should really be paying attention to sea level rise.

PILKEYI think slowly, but surely, there is some public pressure that is making it -- making the public a lot -- and we have a lot of support, editorial support, from the various state newspapers, pointing out how ridiculous ignoring sea level rise is. At one point the state was accused of making sea level rise illegal.

KNOYWell, I have another question that came up, for you Joe Vietri. And this has to do, as we talk about manmade efforts to protect coastal communities. I was surprised to learn, Joe, that many beaches, popular beaches, pump their sand from the deep ocean. They've had so much beach erosion that there's not enough sand left to make it attractive. So parts of Florida, for example, import sand. How does that work?

VIETRIWell, you know, again, this is part of a problem that is, you know, it's national in scope, but it's very regional in terms of its implementation and how they deal with it. In the case of the Northeast, it hits (unintelligible) cases. I mean, everywhere. We basically -- you dredge material from offshore sand, suitable sand, then pump it up on the beach. In the Northeast section of the United States we have a pretty healthy supply of that sand resource sitting off shore and that material can be moved on shore.

VIETRIIn the cases of Florida and some of the other locations around the country, that source of sand is just not there. And so it leaves, basically, folks to go look elsewhere for that sand source, whether it's via trying to get it in from the Bahamas or possibly, let's say, if you're down in Dade County, maybe looking up in St. Lucie County or Martin County for the source of that material. And then using a hopper dredge, which is kind of a big ocean-going dredge that enables you to pump the material back on and then off, move the material down to the beach that's in question.

KNOYOkay. So sand is heavy. Is that expensive, Joe?

VIETRIIt is. And that's exactly where I was going to go with this. I mean, for every mile that you add on this you're basically adding a couple of decimal points in your calculation. And again, as what I said earlier, the economics, at some point, will not hold up. In other words, the cost of doing it will far exceed the benefits attributable to the project. And so that is basically forcing folks, not only here, but overseas as well. Europe, they routinely dredge, you know, look for sand in depths almost as 90 meters, which is just like unheard of here in this country.

VIETRISo at a tremendous cost. But, you know, if the need gets really bad, people will in fact spend that kind of money looking for it. I want to go back to this notion, though, of some of the things that were said earlier with respect to looking at enablers and so on and so forth, as we look in these coastal regions. You know, one of the things that we have been doing for quite a while now is taking into account the future without climate change -- into our future -- future without project conditions.

VIETRIAnd I would just hope that, you know, the Corps is not the only game in town in terms of doing beach restoration. A lot of these walls that are being built in Florida and other places, not even being built by the Corps of Engineers. They're being built by local governments, sometimes under an emergency declarations, as Dr. Pilkey pointed out. So clearly, you know, a national standard where climate change should be worked into the equation at all levels of government would certainly be beneficial and would help, I think, in terms of looking at the economics, sort of level the playing field in terms of what the true costs really are for some of these efforts.

KNOYWell, let's talk another call. This is Barb, in Gary, Ind. And not close to a beach, Barb, but we're glad to hear from you anyway. Go ahead.

BARBWell, actually I am. And that's why I was calling. I am on Lake Michigan, the southern tip of it. And I'm really curious as to whether this is going to effect the Great Lakes in the next couple of decades. And I'll take my answer off the phone. Thank you so much.

KNOYWell, and thank you, Barb. And you're right. You're not on an ocean beach, but on those Great Lakes, sometimes you can't tell the difference, unless you taste the water. I'd love to hear from you, Rob, on this, as we talk about, you know, beach erosion and so forth. Are the Great Lakes suffering the same way that our oceans are?

MOOREYeah, well, first off, due recognition to the Indiana Dunes National Seashore. This is just outside of…

KNOYYes.

MOORE…Gary. It's a beautiful place to go. I've -- I'm from Chicago myself. And have spent some time down there. And it's a great place. The Great Lakes are actually very interesting in this. A study that was done for FEMA two years ago indicated that the Great Lakes are actually one of the areas that -- shoreline areas will be most affected by the impacts of climate change.

KNOYWow, really?

MOOREAlong its shorelines and along its -- the tributaries to the Great Lakes. They are -- they were anticipating that the size of flood plains could increase by as much as 90 percent by the end of the century. So the risks there are a little different because the levels of -- the water levels in the Great Lakes fluctuate for different reasons than the -- than sea levels are going to fluctuate. They fluctuate much more in response to shorter-term weather patterns. And also…

KNOYHeavy rains, runoff?

MOOREHeavy rains, runoff and also the presence or absence of ice in the winter. So as temperatures rise, winter-time temperatures increase, obviously. And you get fewer freezing days. And when you don't have ice on the Great Lakes during the winter you see lake levels fall dramatically. Lake Michigan actually hit historically low levels as -- in 2012 and '13 for this -- because of this phenomenon.

KNOYOkay.

MOOREYou know they had brutally cold winters in the Chicago region in the last two years and there's been a lot of ice cover and those levels have rebounded. But they fluctuate a lot more than sea levels do.

KNOYWell, Barb, glad you called then. And clearly that's an important point as we talk about coastal beaches and so forth, even though they're on the Great Lakes. You know, Orrin Pilkey, I wanted to get your thoughts on this idea of communities, ocean-side communities pumping in sand from the deep ocean, carting it in from other places. What's the ecological impact of doing that?

PILKEYWe've studied this to some extent. Not the ecological aspects, but I think they are pretty obvious. When you dump sand on a beach you kill everything on the beach. And there is an ecosystem on the beach that's quite important. And it involves -- and even the great white shark off shore is dependent, to some extent, on the beach ecosystem. And in addition, when you dredge sand on the Continental Shelf off the beach, you usually kill everything in the area you're dredging.

PILKEYIt's, we all, we see that new types of species, new types of animals come into some of the depression that weren't there before. I think what -- an important point for -- that Joe's made, to add a little bit to that, is that beach nourishment -- the nourished beach -- the artificial beach disappears much faster than the natural beach that have preceded it. In North Carolina our last beach nourishment project, I think, was one on the Outer Banks, just north of Rodanthe. It cost $10 million per mile. And the beach is expected to last three years.

KNOYWow.

PILKEYSo with that kind of cost -- now that's a high waves, they have a lot of high waves there in the Outer Banks, so they disappear faster than other places. But that's not atypical, that high cost and high rate of loss.

KNOYWhat about sand, Orrin, used for concrete, for construction? Where is that pulled from and how does that affect this whole picture of beach erosion?

PILKEYWell, there are -- that has been a problem in some places, especially off the -- off Long Island, the south shore of Long Island where sand has been taken for construction. More often, globally speaking, sand is being taken from dunes and -- so they're losing their protection. And the north shore of -- north end of Morocco is a good example of massive, massive mining of sand. Unfortunately, north Africa has little wood. So they take sand. They -- we argue they should take it from the deserts. But it's easier and cheaper to take it from the coastal sand dunes.

KNOYWow. So they take sand for construction, to build buildings. Let's see if I've got this connection. Take sand for construction to build buildings, which might be, Orrin, knocked down by a big storm because they weren't protected by the sand dune that they took away in the first place.

PILKEYAbsolutely. That's happening in a few little places in Morocco. That's exactly what's happening. You take beach sand, build the building and then in taking that sand, eventually destroys the building.

KNOYOh, Joe, I can hear you want to jump in. Go ahead, please, quickly.

VIETRIYeah, let me add to this a little bit. You know, the usage of sand from the ocean has been done in the Ambrose Channel area, which is sand that would be -- normally have to be removed anyway to facilitate the navigation channel. But at a considerable cost because of the salt content that remains. And the sand has to be washed, etcetera, etcetera. A lot of sand is still mined from sand mines that are inland. But the notion of natural versus manmade beaches is really a function of the grain size and the, you know, the stability of the material itself.

VIETRIIn the case where you're using less than the same grain size sand, it does tend to erode faster. But, you know, through, again, a lot of people do these projects, and not all of them use the same design standards or the same standards to rebuild these jobs. But not all of the material is lost at the end of the three-year period, as Dr. Pilkey just mentioned.

VIETRIIt's basically, at that point in time, the design has been compromised and you have to add more material to it, but certainly not the same amount of material as that was originally there. You know, when you build a beach, there is a long-term commitment there to maintain it. And that's part and parcel of the economics and how that figures into the decision making.

KNOYI'm Laura Knoy and you're listening to "The Diane Rehm Show." Go ahead, Orrin. I can hear you want to jump in. And then we'll go back to our listeners.

PILKEYYeah, okay. That was a very important point that nourishing the beach is a long-term commitment. And in fact, beaches disappear at different rates in different portions of the country. In Florida, along the east coast of Florida a typical beach might last as long as seven years. But in North Carolina and New Jersey, a beach is more likely to last about three years. So every three years or every four years you're going to have to put in another beach.

KNOYLet's take another call, if we could.

PILKEYIt's a long-term thing.

KNOYAnd this is Savannah, in Black Mountain, N.C. Hi, Savannah. You're on "The Diane Rehm Show." Thanks for being with us.

SAVANNAHHi. Thanks for taking my call.

KNOYSure.

SAVANNAHI have a little bit of a two-part question. I'm 22 years old. I'm from the coast of North Carolina. I'm from Brunswick County. And I'm wondering what changes I can expect to see in my lifetime. And I'm also wondering when did scientists start knowing these things, when did the government start knowing these things and why does it always feel like a last-minute scramble to protect our environment? And, yeah.

KNOYSavannah, that's a great question. Thank you so much for being with us. Rob, go ahead. What can she expect to see in her lifetime? She's 22 years old.

MOOREYeah, well, in the next 50 years we'll probably see a foot or more of sea level rise in coastal areas. I think that's a pretty safe estimate.

KNOYAnd put that in real terms for people. 'Cause we hear, you know, X inches or X feet, but just make that real for us, if you could.

MOOREWell, if you looked out your window and lived on a beach today, the water's going to be a lot closer to you 50 years from now. What's more serious, however, is the fact that when you put -- when a foot of sea level rise occurs, it may not have a huge impact on just your day-to-day life. You maybe will see a few more puddles in the streets at high tide. Maybe you'll have -- your basement will be a little damper more often than it used to be.

MOOREThe real risk is that when a tropical storm happens or a storm surge gets pushed in, it's given -- it now has a one-foot head start on you. So a four-foot storm surge may move inland hundreds of yards. It may not make it over the crest of a barrier island, however. You put a foot sea level rise underneath it, and suddenly that four foot storm surge can go a lot further. And that's where the real risks lie, is that we become increasingly vulnerable to events that we might consider routine, but become disastrous because of this incremental sea rise, sea level rise.

KNOYWell, I'm hearing, Orrin, some frustration in her voice. You know, why is it always a last-minute scramble, what do you think?

PILKEYWell, you know, I have a somewhat different view than Rob on this. I think erosion is part of the problem, too. That we have to…

MOOREThat's, yeah, that's also true.

PILKEY…slope the land -- slope of the land is going to control -- ultimately control the rate of erosion. And in most -- on average in North Carolina, a one foot sea level rise will move -- should move the shoreline back, in theory, 2,000 feet or something like that. Behind the Outer Banks, the shoreline will move back about two miles for a one-foot sea level rise, if to the extent that the slope of the land controls it.

PILKEYOn the mainland, behind the Outer Banks, and there a one-foot sea level rise will definitely move the shoreline back four or five miles. I mean, it's really profound what'll happen on the mainland. But we've, of course, been talking mainly about barrier islands.

VIETRIYes. Absolutely correct. Yes.

PILKEYSo.

KNOYWell, and what do you think, Joe? Very quickly. What can Savannah expect to see? Super quick.

VIETRIWell, real fast, I couldn't agree more. I think, you know, we're dealing with three damaging vectors, wave attack, erosion, and inundation. And an increase in one foot will certainly have an effect on all three of those damaging vectors. And it'll be felt differently in different places depending upon where you are.

KNOYOkay. Joe Vietri, thank you very much for being with us. Orrin Pilkey, thank you to you, too. And Rob Moore. Thanks to our listeners. I'm Laura Knoy sitting in for Diane Rehm. Thanks for listening.