New Data on Earth's Climate History

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New data obtained from an Arctic drilling expedition indicates that about 49 million years ago, the Arctic was green, with fresh surface water and ferns covering the water — at least during the summer months. The finding, researchers say, indicates that they may have seriously underestimated the power of greenhouse gases to warm Arctic areas.



Two years ago, an international team of ocean scientists made a daring expedition to the Arctic Ocean. They drilled down to unprecedented depths under the polar ice and brought up samples of sediment, sediment that looked nothing like anyone had ever seen before. Some pieces were bright turquoise blue, even black and white zebra stripe, and now the sediments have been analyzed and even the research team is startled by what it found.

It appears that 55 to 56 million years ago, the weather in the Arctic suddenly warmed up until it was more like Florida or San Diego in the balmy 70s. The scientists even found fossils of ferns and they think this was all thanks to greenhouse gasses, the cause of global warming today. What does that mean then for our climate in the future?

Joining us now is Dr. Kathryn Moran, co-chief scientist of the 2004 Arctic coring expedition. She's co-author of a paper on the expedition's results that are on the cover, the paper's on the cover of Nature this week. She is professor of oceanography and ocean engineering at the University of Rhode Island. Welcome to SCIENCE FRIDAY.

Dr. KATHRYN MORAN (Professor of Oceanography and Ocean Engineering, University of Rhode Island): It's a pleasure to be here.

FLATOW: Andrew Revkin is a reporter who says he's in love with the Arctic. He's been there three times. He covers the environment for The New York Times and he wants to tell young people about the Arctic, so he's written a new book for them called, The North Pole Was Here. And one chapter in the book talks about Dr. Moran's expedition. Andrew Revkin is joining us here in our studios in our New York bureau. Welcome to SCIENCE FRIDAY.

Mr. ANDREW REVKIN (Reporter, The New York Times): Great to be here.

FLATOW: Let's talk about this, Dr. Moran. What was your reaction when you saw this core coming up?

Dr. MORAN: Well, initially onboard we were able to sample a few pieces of the core to actually get an idea of what we were covering. And the first thing that was very surprising was that we were able to recover this important time period in the past that we call the PETM, which was about 55 million years ago. And it was just stunning that we were able to get back, get back - that far back in time. And when we analyzed it later and found out that the temperature of the sea surface at that time in the Arctic Ocean was swimmable, you know, 70 plus degrees Fahrenheit...


Dr. MORAN: It was a very stunning finding and I think we're going to learn a lot more about how the planet responds to these kind of warmings as climate modelers look at these results and see what they think about our findings.

FLATOW: So that means the ocean, the Arctic was cold like we know it and then for some period of time it warmed up, some 55 or 60 million years ago, and then got cold again. Would that be correct?

Dr. MORAN: Well, it, not exactly in that rapid way. We knew before this that that time period was warm on the planet. But we didn't know that it was so extremely warm at the North Pole. 55 million years ago, the location where we drilled was very close to the North Pole as it is today. And that's just a stunning result to get such a high temperature, and such a low difference in temperature between the equator and the Pole. So that's the real major thing.

After that, the - we know from the geologic record that after that, we started to move into what we call the icehouse world. And the transition from the greenhouse world where there was no ice to the icehouse world was important in the Arctic Ocean. And we found that a time period between those two events was a time period in the Arctic Ocean that may have been quite fresh. Some of our scientists think it could even be one of the biggest lakes that ever existed on the planet. And it really suggests that our planet is responding rapidly -relatively rapidly on a geological time scale - to these changes through the interchange of carbon dioxide and other greenhouse gasses.

FLATOW: Now, what makes you think that's the key here?

Dr. MORAN: Well, I'll talk about another period of time that we -- our third major finding was that we recovered what we call ice-rafted debris 45 million years ago. And that's about 35 million years older than anyone had ever anticipated in the past. And that coincides with the cooling of Antarctica. And so if this result holds up; it means that the planet was cooling globally.

In the past, we thought that the cooling of the planet occurred first in Antarctica and then later in the Northern Hemisphere because of tectonic changes, things that would change ocean circulation and that ocean circulation would slowly then cool the northern part of our planet. But this suggests that it's cooling quickly. And to cool and warm the planet quickly means that we do that through the atmosphere, through some kind of greenhouse gasses. So there's a lot of evidence from our samples that suggests that the planet is warming and cooling associated with greenhouse changes.

FLATOW: Mm-hmm. And when you say quickly, that's on a geologic time scale, right?

Dr. MORAN: It is, it is. And we don't know the exact speed at which this happens. But we know at the PETM - that time 55 million years ago - it looks -we don't have the resolution in our time record, but it warmed very rapidly, you know, less than several thousand years.

FLATOW: And what do you have to revise then about your views about greenhouse gasses?

Dr. MORAN: Well, this is not - greenhouse gas studies are not my area, but what we need to do is use these data to begin to basically calibrate our climate models, you know, take a look and see if we can reconstruct what we found in the Arctic Ocean. And once we do that, not - I mean we as a scientific community, we can then improve our predictions for future climate change.

FLATOW: Andy, you're shaking your head.

Mr. REVKIN: Well, the key thing, the climate modelists I've talked to, look at this and they're saying that what's worrisome is that all of the error in their models seems to be on the upside. In other words, the world actually seems to be more sensitive to a nudge in the upward direction. It makes it warmer than they - their models can reproduce. And that to them is a little unnerving, because the models are already saying that if we double the amount of greenhouse gasses in the atmosphere in the next 50, 75 years - as it looks like we're kind of headed toward doing - that you'll have five degree, seven degree rise. And if it's - if their models are overly conservative, then maybe they have to go back to their supercomputers and the figures will come out even higher, which is not a good news scenario if you're trying to figure out how to get through this century with 9 or 10 billion people and lot warmer temperatures and raising sea levels and all that kind of thing.

FLATOW: So it may not take such a large increase in temperature to do some tipping?

Mr. REVKIN: Yeah, they call it sensitivity. The sensitivity of the climate system's been the focus of a lot of papers recently. And you know, in pulling together my book on the once and future Arctic, I've also been looking just generally at this climate puzzle, and there are still components of it that are very puzzling. But, again, they've yet to find a sort of self-limiting aspect of it. In other words, a feedback that's a good news feedback hasn't come around lately.

FLATOW: Right.

Mr. REVKIN: One that would make the world, a warming world kind of cool itself off.

FLATOW: Mm-hmm.

Mr. REVKIN: And that's kind of where they're coming from.

FLATOW: Talking with Dr. Katherine Moran, who is professor of oceanography and ocean engineering at the University of Rhode Island. Andrew Revkin, reporter in The New York Times specializing in the North Pole and the Arctic and author of the new book, The North Pole Was Here; very interesting book for kids if you want to learn. Great, great color graphics and pictures in there. Our number, 1-800-989-8255.

Dr. Moran, there was an interesting - in reading the research here, there was one little rock in particular that sort of stuck out and has been an object of real interest. Can you tell us about that?

Dr. MORAN: Yes, I mentioned that just briefly a minute ago, but we found this pebble that we interpret as being transported to the location of our drill sites 45 million years ago, and transported by ice. And, again, that means that the planet cooled much, much earlier than we had predicted from other evidence in the past. And there's controversy about it, because people could suggest that it could've been transported there other ways, but we have recent evidence that now supports our finding that it was likely that the arctic cooled - the Northern Hemisphere cooled - started cooling about 45 million years ago. So that was quite surprising for us.

FLATOW: Mm-hmm. How many more core drillings do you have to take to satisfy the skeptics about? You know, you have nice core drilling here. But there are always the skeptics around who say, well, maybe it did something wrong; they don't what it is by maybe you did something wrong.

Dr. MORAN: I think its - they have to put this perspective. This was the first drilling expedition into the Arctic Ocean, and we know very little about he Artic Ocean; and so we call this the door opener. The fact that we showed that we could actually accomplish this drilling, stay on location. Right now there's still a lot of sea ice there, believe it or not. And the sea ice can push you off location. So we were able to achieve this under the Integrated Ocean Drilling Program that's funded by a lot of countries together, and in the United States by the National Science Foundation. But we were able to prove that technology and so we see this as just the beginning.

To put it in context, we have many hundreds of drill holes in the rest of the world's oceans, and so that has helped us build our understanding of past climate over the past 55 million years. But now we can actually add to that with more drilling in the Arctic Ocean. There's one particular place we need to recover. We missed about - believe it or not - we missed about 30 million years of record, because it wasn't present in our location. And so there are scientists now putting in proposals to actually drill some new sites on the ridge that we drilled on to recover that time period, which is the transition what we've been talking about the greenhouse world, where there was no glaciers on the planet, to the icehouse world.


Mr. REVKIN: I want to emphasize here the - Katherine's probably being modest to about how hard this is. Having been on the sea ice at the North Pole with a different set of researchers who've been trying to go every year to the same spot and just do the most boring part of science, which is monitoring; where you just take the temperature of the ocean the same way, same year, same time of year. Year in, year out, you just can't do anything up there in a normal way. They had three giant icebreakers, two of them were like fullbacks on a football field blocking the ice so that one ship could stay in one place long enough to just sit there and drill into the sea bed.

And at the North Pole, these guys, they're diving under the sea ice to retrieve instruments they drop once a year through the ice and bring them back up, and everything goes wrong all the time. It's the last real place on earth where you just can't sort of sit around and have a cup of coffee and do your work. And the book kind of - by the way, the reason the book is called The North Pole Was Here is because the science camp they set up at the North Pole every year is moving 400 yards an hour. So if you're at the North Pole now, you put up your little cute little barber post sign says North Pole is here, just cross that out and put North Pole was here, because they're moving. This is not like, it's not like any other place.

Dr. MORAN: Yes. The sea ice was coming at us; it's sometimes up to a half a knot. The sea ice thickness can be up to, you know, several tens of feet thick, and that could push any big ship off location. So it was - we were thrilled to actually be able to accomplish this, and really open the door for real Arctic Ocean exploration.

FLATOW: We're going to talk a little bit more about the sea ice, about the Arctic with Kathryn Moran and Andrew Revkin, author of The North Pole Was Here. Stay with us, we'll be right back after the short break, and see if we can take a phone call or two.

(Soundbite of music)



You're listing to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow. We're talking with Dr. Katherine Moran, co-chief scientist on the 2004 Arctic Core Expedition, professor of oceanography and ocean engineering, University of Rhode Island. Andrew Revkin, who is author of The North Pole Was Here: Puzzles and Perils at the Top of the World. Our number 1-800-989-8255.

Let's see if we can just talk a little bit more about this expedition. Dr. Moran if I were - I'm going to give you the blank check question I give to most of my scientists who are always running out of money - but if you had a blank check and you could do anything in any amount and go anywhere and drill some place, what would you like to do with it?

Dr. MORAN: Well, definitely, we need to go back to the Arctic Ocean. We have just one data point basically spanning a pretty significant time period. But I'd go back to the same - close to the same location to recover this missing time interval that I spoke about which is really the time interval when the planet switched from being really warm to cold like it is today.

And then I'd go over to the other side of the Arctic Ocean on the Alpha Mendeleev Ridge. Scientists have been collecting data there recently that has shown that there may be even a higher resolution. When we talk about a higher resolution, means we can resolve the time much, much more precisely so that we could begin to understand how quickly things happen. And the sediment is thicker there, which means that we'd probably have a higher resolution climate record from the Arctic Ocean.

I mean, our results are so stunning that we really need to go back and first confirm, as you suggested and then try to learn more about these important time periods.

FLATOW: Andy, as someone who's been there three times, what would you like to know?

Mr. REFKIN: Well, again, in order to know where we're going, we have to know where we've been. And the Arctic is a black hole for data. Not just on past climate but even on how much sea ice is there. This - their only records when you go back beyond a hundred years are when whaling ships would go up and they would report where the edge of the sea ice was in the Baron Sea or in, and near Greenland and that's about it.

And then we're trying to put today's great retreat of the sea ice at the North Pole in context, but there's - it's hard to get the context. So even some of the leading ice experts that I talk to about what 's going on with the great retreat we've already seen in the summer around the North Pole sea ice, are still, you know, they can't say for sure absolutely positively that this is our doing yet.

FLATOW: Why not, if we've seen pictures of the North Pole being ice free in the summertime, why not go back in the summer? You don't have to hold the ice back with a couple of icebreakers.

Dr. MORAN: Well, there's still a lot of sea ice there, and it's going to be there for several more years. I think its important for the audience to understand how important sea ice is in the climate system. It's like a white blanket at the top of the world that actually reflects energy and helps moderate our climate. And so it is - it could be one of those triggers we talked about whether - when it started and when it goes away.

And in our record that we collected, we're still analyzing the cores and we're hoping, as Andy has suggested, we're hoping to reconstruct at least the beginning of what I call a sea ice story; the history of the sea ice from the Arctic Ocean and begin to truly understand when it started and whether it waxed and waned with time, et cetera so getting that past record. It's really the only gauge we have to really ground truth how the earth responds to these kinds of fantastic experiments like we're doing today with our CO2.

FLATOW: Well, thank you very much for joining us, Dr. Moran. And good luck to you and please come back after you've done that next core sample.

Dr. MORAN. Okay, thank you will do. Thank you very much.

FLATOW: Katherine Moran, co-chief scientist on the 2004 Arctic Core Expedition, professor of oceanography and ocean engineering, University of Rhode Island. Andrew Refkin. Thank you, Andy.

Mr. REFKIN: It's my pleasure.

FLATOW: And the terrific new book, The North Pole Was Here: Puzzles and Perils at the Top of the World For Your Kids. And being a big kid myself, I enjoy looking at those nice pictures. Thanks, Andy, for being with us.

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