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Valley Public Radio Staff
Tue September 11, 2012
Arctic Sea Ice Melt Sets Record
Originally published on Tue September 11, 2012 11:46 am
NEAL CONAN, HOST:
Every summer, some of the ice that covers the Arctic Ocean melts. Come mid-September, it begins to refreeze. Scientists began to monitor this cycle in the late 1970s, and this year, they saw less ice than ever before - a lot less ice. NPR science correspondent Richard Harris joins us here in Studio 3A. Richard, nice to have you on the program.
RICHARD HARRIS, BYLINE: Always a pleasure, Neal.
CONAN: And how big is this change?
HARRIS: It is big. The previous record was in 2007, where a very large percentage of this ice melted away. This year, it's already bigger than 2007 by an area the size of Texas. This is - this really shattered that record which in itself was a pretty dramatic departure from the average.
CONAN: And, well, if things melt, it's because things are warmer, right?
HARRIS: That is exactly right. And what happens also is the Arctic ice has been getting thinner over the years. And so it used to be that you can have some warm summers up there, and you wouldn't melt it all away because you'd have 10 feet or 20 feet thick of ice. And you'd melt some of it, but you wouldn't melt it all the way through. But because of this warming trend up there, it is where the planet is warming faster than anywhere else. The Arctic, what we've seen is the ice getting thinner up there. And so a fairly small pretubance will actually melt a lot of the ice because it's thin to begin with. You don't have to melt 20 feet of ice. You might melt three feet of ice.
CONAN: And you mentioned 2007 was the previous record. How were the intervening years between 2007 and this year?
HARRIS: Up and down, actually. It's not a steady trend where every year gets worse as it goes. In fact, it - we haven't been near as bad as 2007 until this year but - so - but 2007 was a big bump down and then sort of rattled around in that area. We've got it close a couple of years, but nothing this dramatic until this year.
CONAN: And scientists as they saw this, are they - how big a deal is it?
HARRIS: It's a big deal. I think for them they are - they used words like astounding and dramatic and so on, the words that are that really are, you know, make - draw the point that this is a really big change, and it's obvious. It's - there's just - this is not a small thing. This is huge.
CONAN: And why is it important?
HARRIS: It's important because it is, for one thing, the most visible sign of climate change. There's little question that this is as a result of global warming that this is happening. And so that's one thing. The next thing is, of course, the ecosystem at the Arctic depend upon a certain amount of floating ice. The walruses dive off of it. The polar bears rely on it - the seals and so on. It's an important part of that ecosystem up there. So it has some local effects. But what's also becoming more and more apparent is it's going to be affecting our weather down here because you're going - when you get an extra degree of warmth up in the far north, you're going to change the way weather patterns move through the rest of North America.
And we could - I talked to a scientist today who said we could be seeing things like those really slow-moving big, heavy snowstorms that come along. It's not that there would necessarily be faster storms or whatever. In fact, it's just the opposite. There would be slower storms as a result of this pattern, and as a result, instead of just moving on by not causing so much grief, you can get huge amounts of snow and ice dumped on us here, and not only here, also in Russia. We have, of course...
HARRIS: ...this past summer was very mild here. But when it's mild here, you need to look around the rest of the world and say, was it mild everywhere? And the answer is usually no.
CONAN: Well, just along those lines, we read reports that temperatures in the contiguous 48 states have been above average in each of the last 15 months, which has never happened for as long as people have been keeping records, and that 2012 is on track to be the warmest year ever. As we read about this record Arctic ice melt, is this a coincidence?
HARRIS: Well, it's all part and parcel of the same thing, but I will say that January through August of this year has been the warmest period - January through August period since 1895 when they started taking temperature records. That's in the contiguous lower 48. Alaska has actually had a fairly average year, so everything doesn't march in lockstep. But again, the situation with the ice and the Arctic is this has been accumulating over decades of warming up there, and we're finally seeing the results of that.
So this one summer was not at all a key up there. In fact, what was interesting to one of the scientists I talked to, he said, basically, you know, what was astounding about this was that there was no astounding weather pattern up there that explained this dramatic difference. It was just kind of reaching this point of where the ice was just so thin that it was just ready to crumble.
CONAN: Ice is white. It reflects light. The sea is blue. It does not reflect light. It absorbs it, and thereby, the heat that comes with it.
HARRIS: That's right, and that makes the big difference. We're essentially taking a mirror off the top of our planet, and that means that the planet's absorbing more heat. That heat does go into the ocean, that warms the ocean. What's going to happen when the ice starts to freeze up again - which it will this fall - is all that heat, a lot of that heat has to come out of the ocean before the ocean temperature gets to the freezing point again and can freeze. And so we're going to have a huge outflux(ph), I guess, of heat out of the ocean back into the atmosphere. But - because it's been building up there. So not only did the warm water helped melt the ice, but now, it's going to come out. And that's - that feeds into the change in weather patterns I mentioned earlier.
CONAN: And also this open water in places that have always been frozen over before, that exposes these areas to economic activity that has never happened before. The Northwest Passage usually thought of as - well, if frozen, you really can't get through there without some nuclear-powered icebreaker or something. This is now an area of enormous economic exploitation.
HARRIS: It is. It's starting off. There was a cruise ship that watered into Barrow, Alaska, a year ago, which was surprising to everybody because you shouldn't have a cruise, you know, they weren't prepared for a cruise ship to land in this tiny Arctic outpost. But it's a funny thing because it's not consistent, even though this has been a really low ice year.
Just today, Shell oil announced that it had to pull out of its oil drilling, which just despite it started yesterday in the Arctic Ocean, you know, in the Chukchi Sea because they had discovered that there was a 30-mile long iceberg heading towards them. And they had to get out of the way. So even on - even in periods where there's a lot of ocean water that's just plain open, ice is still a hazard up there, and it will be for decades to come.
CONAN: And as this trend continues, you said, globally, is it true in Antarctic as well? There's a lot of ice in the ocean that's around the Antarctic continent?
HARRIS: Yeah. It's a little more complicated in Antarctica because what happens is, for one thing, the southern ocean around Antarctica is warming up. There's a - the temperature measurements have been - are clear on that. But what happens around as a result of that is you had to put more precipitation. So you actually have expanding sea ice around Antarctica, at least in the wintertime. In the summertime, it all melts away or almost all of it melts away. And it has for a long time because it's a very different situation from this closed bowl of an ocean in the Arctic where the ice can pile up and get thicker and thicker. In the Antarctic, that's never been the case. It always has melted away. So it's not a big change down there. A little bit - the extent of the wintertime ice is a little bit broader than it has been before.
But, again, getting back to your discussion of the mirror and ice being reflective, that's less important in the wintertime when that's at its maximum extent. And in the summertime, it melts away pretty much every year.
CONAN: In getting back to the northern region, the Arctic, is - scientists had long feared that if this trend continues, there will come a summer where there's no ice at all.
HARRIS: Yeah. I think people are starting to back away from that a little bit because there are enough little pockets where you could get some ice accumulating every summer and not melting out because, basically, you have the wind that pushes that together and piles it up. So you have always have a few places where it's piled up. But on the other hand, that will be a fairly small part of the Arctic, quite a small bit. So it's not - so for practical purposes, the ocean will look ice-free, and the North Pole may be sort of in a large area of no ice at all. Occasionally, right now, there are cracks and there are openings that drift around. And so, sometimes, the North Pole itself is in an ice-free area.
CONAN: Open water, yeah.
HARRIS: But it could be possible to be in a large area of open water in the coming decades. That's the expectation.
CONAN: The other enormous area of a white, reflective surface is the ice cap that covers the island of Greenland, the biggest island in the world. And that this summer also had a really powerful melt.
Yes, and that's a very different situation because the ice sitting on the ocean, when it melts, it doesn't change sea level. If you think of a glass of ice tea and you put your ice cubes in the ice tea, when the ice melts, your ice tea, obviously, doesn't overflow. The ice just - it...
There's quite a difference in volume, but not big enough.
HARRIS: Yeah. It basically doesn't - but the melting ice that's floating doesn't matter, but what - but a lot of the ice sitting on Greenland and on Antarctic, the continent of Antarctica, when that ice melts, that does, in fact, add water to the sea. And those are in the long term, likely to drive the sea level rise and could drive the sea level rise by a great deal in the coming decades and centuries.
CONAN: So is anomalous - I mean, is this - as you said, it's definitely part of a trend. There's no way to argue with it anymore, about the warming and that it's having real effects. How is it going faster than people feared?
HARRIS: Yes. I think if you talk to those scientists who've done the computer models and are projecting how quickly things will happen, a lot of those models will say that the ice could be largely gone by 2030, 2040, 2050. But they say, what we're actually seeing is outracing those computerized trends. So the computers in this case are giving an optimistic picture, compared to what we're seeing in real life here. So, yes, this is a real eye-opening event for people.
CONAN: And that suggests to people in this country, as they look around to the weather that we've been experiencing these past couple of summers, that they better get used to it.
HARRIS: That's right. I think - I mean, there are still obviously a lot of skepticism in this country about whether a global warming is real or not, or whether it's - at least whether it's caused by human activities. Scientists don't argue that point by and large anymore, but I think a lot of people in the public do. But I think it has come to the point where people can't say, well, it's - people at least have to acknowledge it's hotter now and getting hotter and has been hot for a long time. And this is, you know, this is a new normal for us. And whatever you believe about the politics of this, you have to acknowledge this is something we have to get used to at least and maybe think seriously about, you know, is there a way to put a brakes - the brakes on this?
CONAN: Richard Harris, thanks very much for your time today.
HARRIS: It's my pleasure.
CONAN: NPR science correspondent, Richard Harris, joined us here in Studio 3A. He'll be back later today with more on the record ice melt on ALL THINGS CONSIDERED. You're listening to TALK OF THE NATION from NPR News. Transcript provided by NPR, Copyright National Public Radio.