High Mountain Glaicers
Narration: Jefferson Beck
Transcript:
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[Aircraft noise, music]
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Alex Gardner: My interest in glaciers
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comes from the sheer size of these things and
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how much they’re able to change on human timescales.
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[waterfall noise] And so the amount of mass and energy being transferred
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by glaciers around the globe is tremendous,
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and it’s an absolutely fascinating thing to study from space.
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[waterfall noise builds, intro music kicks in]
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Narrator: Mountain glaciers are some of the most charismatic parts
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cryosphere. Some might cling to the edges of cliffs
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[music rises] at higher elevations, then lay bare and flat in a broad plain,
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looking cracked and weathered like elephant skin, before tumbling
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thousands of feet toward the sea, and terminating in a dramatic
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calving front. They’re like motion frozen in time - [iceberg calves]
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until they aren't. They tell a story about
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the distant past, and yet are incredibly responsive to the present.
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You can understand why they’d be captivating to all of us,
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and especially cryospheric scientists.
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Meet Alex Gardner, a cryospheric scientist at NASA’s
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Jet Propulsion Laboratory, who is going to help break down what a classic
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west coast North American glacier might look like, where high amounts of snow
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dump on to the mountains. Gardner: And at higher elevations,
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there’s melt in summer, but not enough melt to get rid of all that snow. So that snow
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it compacts, it turns into ice, and it starts to flow under its own weight.
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And it flows down the valleys. As it flows down the valleys, it actually
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it actually carves those valleys out and it makes them deeper. And so it creates these beautiful fjords
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where the ice flows down, it snakes out to the ocean
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or to the lakes or further inland. And so that ice is flowing. It’s moving.
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[music builds] Narrator: Alex uses satellite data to study large-scale changes
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. But two thousand miles to the north, Chris Larsen
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from the University of Alaska Fairbanks spends a lot of time studying
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glaciers from the air. He’s been flying over Alaskan
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mountain glaciers for many years, most recently on a NASA-funded mission
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[water fall noise] called Operation IceBridge Alaska. He’s absolutely
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enamored with his local rivers of ice.
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Interviewer: And what do you love about mountain glaciers? Chris Larsen: Well, they're in mountains
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so they're really pretty! You couldn't ask for a better way to experience
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Alaska on a large scale than to go flying around for campaign after campaign
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and to look at all the mountains in Alaska -- truly infinite.
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You just feel like you'll never see the end of them, and you don't want to.
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Narrator: But Chris doesn’t spend weeks away from home
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and family for the views. Chris and his colleagues at NASA want to answer
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some pretty big questions by learning more about Alaskan glaciers
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and how they tick. Larsen: You know, why does NASA care about these?
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Well, they actually disproportionately contribute a large amount to sea level rise.
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Narrator: In the long run as the Earth warms due to climate change,
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the big ice sheets and mighty outlet glaciers of Greenland and Antarctica
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stand to contribute the most to sea level rise, simply because
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the vast majority of the planet’s ice is stored there. But currently,
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it’s the world’s smaller mountain glaciers in comparatively warmer places,
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places like Alaska and Patagonia that are contributing about a third of all
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inputs to sea level rise, even though they account for only
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1% of the world’s ice. Larsen: It’s mostly due to them
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them being dynamic. They have water at the bed, which allows them to slide
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fast, and they react quickly to climate change
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and have higher velocities than their polar counterparts.
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Narrator: Back at JPL, Alex uses satellite measurements
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of global ice and computer models to predict ultimately,
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how much sea level rise we might see due to climate change.
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But in the case of mountain glaciers, we also care about the local impacts
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of disappearing ice.Alex:When we think of changes in ice sheets,
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we typically think of just what is the consequence for sea level rise
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and the future evolution of the ice sheets. But glaciers in other regions, like high mountain Asia,
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Alaska, the European Alps, these are places where
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these are places where changes in runoff matters to stream flows.
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In places like high mountain Asia, you have a lot of glaciers that feed the streams
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that flow down to populated regions. And that runoff
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becomes significant for water resources, irrigation, and agriculture.
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Narrator: Both Alex and Chris are passionate about
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understanding how glaciers are changing and what it means for our planet’s future.
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They’ll continue to use tools like elevation maps from the
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ICESat-2 satellite and detailed airborne measurements to monitor changing ice.
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[music fades, teaser music builds]
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Peter Griffith: by the end of the tunnel you're about 100 feet under ground, and you're surrounded by
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bones sticking out of the wall from the steppe bison and the
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mastodons, there's sticks that are 40,000 years old
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there's grass that's still green, that's tens of thousands of years old.
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[music ends]