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