Underground Lakes May Help Explain Glacier Habits
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Scientists have discovered a vast network of lakes beneath the ice in Antarctica. That discovery could help them resolve one of the great outstanding questions about global warming. The question is how quickly the Earth's vast glaciers might melt, which would affect how quickly sea levels might rise.
NPR's Richard Harris reports.
RICHARD HARRIS: Antarctica may seem like a block of solid, unmoving rock and ice. But in recent years, scientists have become increasingly aware that the place is on the move. And that's because there's actually water in pockets deep beneath the ice.
Ms. HELEN FRICKER (Researcher, Scripps Institution of Oceanography): There's 145 documented lakes. There's more being discovered all the time.
HARRIS: And Helen Fricker from the Scripps Institution of Oceanography has just discovered a new network of lakes nearly half a mile below the ice. The biggest one in the chain stretches for than 100 square miles. And these lakes aren't just sitting there. Fricker and her colleagues report in an article to be published in Science magazine that water is moving rapidly under the ice, from one lake to another or even flowing out to sea.
Ms. FRICKER: It's totally amazing to think that there might be liquid water existing underneath the Antarctic ice sheets. It's amazing. And to think - and then to think that it's moving around at such rapid speed, that's the most surprising thing.
HARRIS: And this is not simply a curiosity. The newfound network of lakes sits under some of the rapidly flowing glaciers in Antarctica. Fricker expects that's not a coincidence.
Ms. FRICKER: Water underneath the ice lubricates the ice and causes it to flow faster.
HARRIS: And we care about that because this ice is flowing toward the ocean. If it slides off the continent and plunges into the water, sea level will rise. The problem is scientists so far don't understand the flow of these glaciers well enough to predict what's going to happen to sea level in a world of more global warming.
Ms. FRICKER: The reason why it's important for global warming is that we need to make predictions under a warming climate. We need to know how the Antarctic ice sheet is going to respond.
HARRIS: Elaborate computer models can make time run fast to see what our world would look like in the decades to come. But they're only as good as the information that goes into them.
Ms. FRICKER: Currently, this process that we've identified under the ice streams is not incorporated because it wasn't known about.
HARRIS: Ian Joughin from the University of Washington has been puzzling over ice behavior, both in Antarctica and in Greenland. Up north, warming temperatures are already triggering some rapid variations in the Greenland ice. Some ice streams are moving faster but they're also getting thinner. So they are actually putting less ice into the ocean. But he says that could change rapidly.
Professor IAN JOUGHIN (Glaciologist, University of Washington): The changes we've seen show that there could be really large changes in Greenland and that they are really something to worry about in Antarctica, too. But we don't have a good predictive capability yet to say where those changes are going to go and how they're going to affect the ice sheet.
Ms. FRICKER: But Joughin is optimistic that as scientists discover more features like the under-ice lakes, they'll finally start to understand what's driving this surprising ice behavior, and they'll be better able to predict what the glaciers and sea level will look like in the decades to come.
Richard Harris, NPR News.
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