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IRA FLATOW, host:

Up next, an alarming study about Alaska's crumbling coastline. You've probably heard about arctic ice melting because of climate change, but how about melting dirt? It may seem strange, but it's a reality for people who live in places like Alaska, where much of the coast is made of permafrost. We have the ice and the soil are basically one in the same.

And so when the permafrost on the Alaskan coast melts because of warming temperature, the dirt goes with it right into the ocean, leaving a mess of issues for the people living on a dwindling shore. And in some cases that shore is dwindling now in some places in Alaska at an alarming rate.

Here to talk about a new study that measures the rate of erosion on part of that Alaskan coast is Chris Arp. He's a research ecologist for a branch of the U.S. Geological Survey called the Alaska Science Center. Welcome to SCIENCE FRIDAY.

Mr. CHRIS ARP (Research Ecologist, U.S. Geological Survey): Thanks, Ira. It's good to be here.

FLATOW: Tell us about this Alaskan erosion, 45 inches per year?

Mr. ARP: Forty-five feet per year in…

FLATOW: Forty-five feet per year.

Mr. ARP: That's right - in the area that we're working. But I just want to stress that the Alaska coastline is one of the - is about 6,000 miles long, which is quite a bit longer than the rest of the coastline in the lower 48. In the area that we actually studied, there's only about a 40-mile segment that's located along the Beaufort Sea Coast.

FLATOW: Right.

Mr. ARP: But what we found at this particular area is that for the time period that we have aerial photography to actually analyze the change in the coastline position, that erosion rates have gone from about 22 feet per year from 1955 to '79, 29 feet per year from '79 to '02 and then in the last five years, about 45 feet per year.

And I also want to stress that that's just an average for that stretch of coastline. And there's parts of that same coastline that are actually building from a deposition of sediment and then other areas that are eroding much, much faster than 45 feet per year, rather.

FLATOW: And so why are you so interested in this particular area that you're studying?

Mr. ARP: Well, that's interesting actually. I guess the main reason's actually concern for a small goose - it likes to molt there, called a Black Brant. And so this segment of coastline is part of the Teshekpuk Lake Special Area, which is part of the National Petroleum Reserve and it's called a special area primarily because it provides critical wildlife habitat mostly for migratory birds, but also a resident caribou herd.

And so the USGS got some funding to help try to understand how climate change was impacting wildlife populations in that area. We should start this kind of multidisciplinary study. And the lead author on this work, Ben Jones is a geographer who's been working in that area for quite awhile along with Ken Hinkel who's at the University of Cincinnati and two wildlife biologists Jules Schmutz and Paul Flint.

So, it was an interdisciplinary project. And part of that was trying to understand coastal erosion and actually how that impacts lakes, what these geese use for habitat.

FLATOW: And what is causing this accelerator erosion? Are you pretty sure that it is climate change, global warming?

Mr. ARP: Well, you know, it's a pretty complex system up there, and I guess I should probably explain just a little bit more about how erosion works there, compared to other types of environments. So as you already mentioned, it's a ice-rich permafrost environment. So in the upper, say, 10 feet of soil, you can have an upwards of 90 percent ice within that soil column. And so when heat gets applied to that, and that ice melts out, the ground subsides and, you know, falls into the ocean.

So erosion there actually works by what's called thermo-erosional, or thermo-mechanical niche erosion. And so once the ice actually moves away from the coastline, I wanted - also want to stress that about 75 percent of the year that the ice is actually frozen right up against the shoreline. So there's actually no erosion going on. But once that moves away, and the open water can contact at the base of the bluff, it starts carving a wedge back underneath this block.

And once it gets back there far enough, which may be, you know, 10 feet, 30 feet, the block will actually collapse off and fall into the ocean and then that can melt away - the ice in that can melt away pretty quickly. And then kind of that episode starts again. And so, I think you're probably aware that the sea ice has been declining much more rapidly than it had been predicted in 2007 - I think was the record low fall sea ice extent.

FLATOW: Right, right.

Mr. ARP: And so having ice move away from the coast that much faster allows probably a longer period of time for that erosion to occur some more of these ice block collapse episodes.

FLATOW: So the ice was protecting this - the coastal area. Now there's no ice there to protect it. And you have the wave action getting in and eroding it even further.

Mr. ARP: Yeah. That's right. That's right. And then so, also, storms used to be probably one of the main drivers of erosion in this area. They probably still are, but now I think storms can actually be more effective because the ice is so much farther out, that there's more fetch. And there's also some evidence that sea surface temperatures have risen quite a bit.

And so, again, that's applying greater heat to these ice-rich bluffs that may be accelerating this erosion. And so we have actually seen, like, a shift where in the past we think that kind of the ice-rich areas were more resistant to erosion.

FLATOW: Right.

Mr. ARP: And now that we have these kind of warmer water conditions that they may be more susceptible to erosion.

FLATOW: And how do all the people living around here react to this?

Mr. ARP: Well, okay, so in the Teshekpuk Lake area there isn't anybody living there right now. It's pretty important subsistence grounds for the Inupiat people for both hunting and fishing. But the closest community of any size is Barrow, Alaska, which is about 100 miles to the west of this area.

So, you know, I think there's a fairly good chance that if we were not there doing this work, there's been other people that have been out there doing work as well, but if scientists weren't out there doing it, people might not know about it.

FLATOW: Yeah, so you went out there for one reason and found something else?

Mr. ARP: Well, we went out there with the interest in trying to understand a lot of different aspects of the ecosystem related to both climate change and how to manage both wildlife and petroleum resources in that area. And so, yeah, I would say that wasn't our main focus.

FLATOW: All right. So where do you go from here with this?

Mr. ARP: Well, our main focus at least Ben Jones and I, who, again, is the lead author in this paper, are really interested in studying lakes in - that are set in permafrost, which are called thermokarst lakes. And they actually go through the same kind of sequence of erosion to some degree, where they're an ice-rich permafrost and will actually move or erode into these lakes and they'll expand. Sometimes they'll drain.

And Ben actually just started his PhD at University of Alaska Fairbanks. And he, the reason he couldn't be here to do this interview is that he's out - a field camp on the Seward Peninsula studying thermokarst erosion on these lakes and actually how that process influences methane evolution, which is just methane released from lakes.

And I think, as you probably are aware, that methane's a very strong greenhouse gas. And so trying to kind of understand how lake shoreline erosion influences those processes is another pretty exciting area, so…

FLATOW: Yeah. Let me just remind everybody that I'm Ira Flatow and this is SCIENCE FRIDAY from NPR News. Yeah, I'm sorry, go ahead. I just had to jump in there. So, that's going to be part of the next process here, understanding the lakes?

Mr. ARP: Yeah, yeah. I mean, that was actually kind of our initial focus going into this project. And it still has been, understanding the lakes in this area. It's a very lake-rich area. There can be upwards of 20 to 30 percent of the land can be covered by lakes. And so it has a huge influence. I mean, of course, for wildlife habitat, but also just how it influences the land and interacts with the climate, with the atmosphere.

Just because the lakes, when they freeze, the albedo, the reflectivity of lakes is very different from - when they're thawed out. And so that's a big surface area that can interact with the climate. But a lot of the work we're - the USGS is really focusing on - is trying to understand how to support wildlife resources and how try to understand how climate change is going to influence those and how we can better manage wildlife resources, knowing more about how those ecosystems might change.

FLATOW: And the Arctic regions are the places where we see them happening the fastest.

Mr. ARP: Yeah. That's really true.

FLATOW: And I guess on the one hand that's true, but it's also a place where you can study them more easily, I would imagine.

Mr. ARP: Mm-hmm. Yeah, that's really true. I mean, it's a really exciting place to be working just because things are changing so fast. That it just, you know, provides a great opportunity to try to understand just basic ecosystem processes, which I think is probably one of the most critical things that, for example, the modeling community needs.

FLATOW: Yeah.

Mr. ARP: To try to make, you know, sound predictions.

FLATOW: That's what Dr. Lubchenco was talking about was creating a climate prediction center, just like weather forecasting, to have climate forecasting and know what to expect in those parts where, especially where, you know, the Arctic areas where things are changing so quickly. What do we expect to happen here? How much land do we expect to lose, you know?

Mr. ARP: Well, yeah, that's a great question. And I think - how do I go about this? Okay. So, I mean, currently we're working with a civil engineer who's trying to do predictive modeling based on kind of a lumped model, so it isn't spaciously distributed. He's using some of our data sets. But the area that we're working, really, is pretty data poor, both in characterizing the shape, the land and the sea floor around there. But then, also, you know, like the closest title gauge, I think is in Prudhoe Bay. So, you know…

FLATOW: Wow. So, you've got a lot data to collect.

Mr. ARP: Yeah, that's right. So…

FLATOW: Before you make your model. I'm going to have to interrupt.

Mr. ARP: Sure.

FLATOW: We've run out of time. But I want to thank you for - and wish you good luck in your research out there.

Mr. ARP: Yeah. Thanks a lot for your interest.

FLATOW: You're welcome. Chris Arp is a research ecologist for branch of the U.S. Geological Survey called the Alaska Science Center in Anchorage.

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