((PKG)) ARCTIC DRILLING
((Banner: Secrets of the Ice))
((Reporter/Camera: Steve Baragona))
((Adapted by: Philip Alexiou))
((Map: Greenland, East Grip Camp))
((TREVOR POPP, UNIVERSITY OF COPENHAGEN))
We're here to drill an ice core to the bedrock.
((Popup Banner: Meet the scientists drilling through 2.5 km of Arctic ice for clues about the climate's past, and future))
((TREVOR POPP, UNIVERSITY OF COPENHAGEN))
Minus 28 in there. Just come in and look to your right. You'll see an ice core, I think.
((TREVOR POPP, UNIVERSITY OF COPENHAGEN))
So, this ice comes from 754 meters down, and it's on the order of 6,000 years old.
The snow that we're getting in this ice core did not fall at this spot because this is an ice stream that's moving. So this snow fell some hundreds of kilometers away from here and has moved to this spot. At this depth, we can still see one year to the next to the next to the next. So, when we study the climate, we are actually getting information for every year. So, we get the seasonal signals in dust and water isotopes and other impurities that tell us about atmospheric circulation. They tell us about the temperature. They tell us about processes in the ocean and then the bubbles will give us the concentrations of constituents in the atmosphere -- methane, carbon dioxide, nitrous oxide.
((JORGEN PEDER STEFFENSEN, UNIVERSITY OF COPENHAGEN))
So we are pulling these cores out and the bubbles have 60 times atmospheric pressure, then the ice can't hold it. So it becomes explosive, so it starts to crack on the table spontaneously and all the gases escape.
((TREVOR POPP, UNIVERSITY OF COPENHAGEN))
And as a driller and scientist, it, kind of, breaks your heart when you do all this. You get these beautiful cylinders up, put it on the table and it starts to just, pop, pop, pop, pop, pop. You can hear it like rice crispies (cereal).
((JORGEN PEDER STEFFENSEN, UNIVERSITY OF COPENHAGEN))
And that's what we call a brittle zone. And it's really, really terrible as a glaciologist to watch this perfect core disintegrate in front of your eyes. So, we actually, and this is, it sounds completely ridiculous and backwards, but actually we mounted a freezer unit in a snow cave inside the Greenland Ice Sheet and that is simply to control the temperature.
We say, well what do you say, oh it must be cold in there! Yes, but it's not cold enough so we are putting a freezer inside the ice sheet. That, that's hilarious. But anyway, so we know that Greenland now is shrinking because there is enhanced melting around the sides. Very easy to understand, because it corresponds to rising temperatures at the coastline. So, you will have much more runoff. And that will make the Greenland Ice Sheet lose mass. So right now, I think, the contribution of the Greenland Ice Sheet to world sea level changes is just beginning to show, but we don't know if this shrinking is going to be a linear, straightforward process that you can predict. And that's why we're drilling at East Grip.
((JORGEN PEDER STEFFENSEN, UNIVERSITY OF COPENHAGEN))
You can monitor the surface.
((JORGEN PEDER STEFFENSEN, UNIVERSITY OF COPENHAGEN))
The trouble is all kinds of funny stuff is going on at the base of the ice sheet.
If something odd is going on at the base in these ice streams, and there are a lot of ice streams in West Antarctica too, then it can upset the entire applecart. All of a sudden you would have an unstabilized sheet that might break away, not over several centuries, but over a couple decades. And that would be disastrous.
((NATS))
