Visiting the most vulnerable place on Earth: the ‘doomsday glacier’

JUDY WOODRUFF: The Thwaites Glacier is one
of the largest glaciers in Antarctica, and it is melting at an alarming rate. The world
took notice earlier this month when temperatures there hit nearly 70 degrees. But getting a better read on what’s happening
has been a challenge. Our science correspondent, Miles O’Brien,
gave scientists David Holland and his team camera equipment to document their mission
to the glacier. Miles has this dispatch, as part of our series
the Leading Edge. MILES O’BRIEN: It’s an urgent scientific mission
at the far edge of what’s possible, to the edge of a massive melting glacier. It’s the largest, most menacing source of
rising sea levels all over the world. Welcome to the Thwaites Glacier in West Antarctica. Our guide on this journey is David Holland
a professor of math and atmosphere/ocean science at New York University. He is a principal
investigator on the MELT Project, part of the International Thwaites Glacier Collaboration. The five-year campaign is funded by the U.K.
Natural Environment Research Council and the U.S. National Science Foundation, a “NewsHour”
funder as well. Why is Thwaites so important? Why is it worth
the effort? DAVID HOLLAND, New York University: So, it’s
the most vulnerable place on Earth. And the curious thing is, how is it that it’s so vulnerable
and, at the same time, it has warm water in front of it today? These are just two things that may be coincidental,
but they’re both real, and they’re happening. MILES O’BRIEN: For years, scientists have
warily watched Thwaites from afar, using NASA satellites. About the size of Florida, it
is vanishing at an alarming rate, retreating about a half-mile and thinning as much as
15 feet every year. It sits on land below sea level. There is
nothing to stop its accelerating retreat. It could melt away in a few decades. Some
call it the Doomsday Glacier. If Thwaites were to melt or drop into the
sea tomorrow, how much sea level rise would we expect? DAVID HOLLAND: So, it’s less than a meter.
It’s probably on order of, say, 65 centimeters. Then the neighboring ice would become unstable.
And so, altogether, it would be more than three meters of ice, something of the scale
of 10 feet. It’s a major change, a rewriting of the coastline. MILES O’BRIEN: Thwaites is like a cork in
a bottle. Once it is gone, there will be nothing to stop a cascading loss of nearly all the
glaciers in West Antarctica. That is why Holland wanted to come to this
place, to drill a half-mile hole through the ice to see what’s happening underneath. It’s
never been done before, and it very nearly didn’t happen this Antarctic summer. DAVID HOLLAND: The motto for me is, have no
expectations. If you have expectations, you will be deeply disappointed. MILES O’BRIEN: In November, they flew to Christchurch,
New Zealand. Within a few days, they were on a U.S. Air
Force Air Mobility Command C-17 stuffed to the gills with scientists, support crews and
gear. After a five-hour-long flight due south 2,300 miles, they landed at McMurdo Station,
headquarters for the National Science Foundation in Antarctica. But they were still more than 1,300 difficult
miles away from their camp on Thwaites, and the weather was terrible, and the airplanes
kept breaking down. What was to be a one-week stop at McMurdo for briefings, training and
practice became more than a month. By the time they got to Thwaites, all the
weather and mechanical trouble left them barely enough time to do their science, but safety
first. SETH CAMPBELL, University of Maine: We’re
at the grounding zone for Thwaites Glacier right now. MILES O’BRIEN: A team led by geophysicist
Seth Campbell of the University of Maine surveyed the area. He explored some nearby caves. SETH CAMPBELL: That thing has never been seen,
probably. MILES O’BRIEN: And towed a ground-penetrating
radar on a sled to identify perilous crevasses beneath the surface. SETH CAMPBELL: If you zoom in here, we can
show you what they look like. The way radar works is, we’re imaging layers
in the snowpack below us. So, we can see there’s crevasse here. And we can see there’s actually
a crevasse here as well. MILES O’BRIEN: Others were more obvious. Working
on the edge of a glacier is dangerous business. A wrong step would be fatal. MAN: I think we will go around this one. MILES O’BRIEN: They also looked beneath the
ice using another technique called seismic reflection, ironically often used by the oil
industry to find places to drill. But, in this case, they are making an underground
map to ensure they are where the ice transitions from sitting on the rock to floating in the
ocean, the so-called grounding line. They detonated some small buried explosives,
akin to fireworks. Lizzy Clyne is a doctoral candidate at Penn
State. ELISABETH CLYNE, Penn State University: When
we set off that explosive charge, that creates a bunch of seismic energy that radiates down
through the ice to the bed, to the bottom of your shelf. Any sort of change in material will trigger
a reflection that comes back to us. And so, this way, we can see whether there’s water
or there’s sediment or there’s rock beneath the ice. MILES O’BRIEN: The reflections they recorded
showed the ice, the seafloor, and a thin column of water, a bullseye, exactly where the team
wanted to drill. They don’t use drill bits here, just hot water,
nearly boiling. The rig requires several aviation fuel-powered burners attached to a long spool
of hose. DAVID HOLLAND: We see the drill rig, and then
the hose goes down through a hole in the ground here. Right there. MILES O’BRIEN: Is it risky, ultimately, to
the glacier itself? DAVID HOLLAND: No, because it’s such a small
fraction of the glacier. We’re like, literally, touching one-millionth of a percent of the
glacier. MILES O’BRIEN: When they finally got started
drilling, a big storm blew in. DAVID HOLLAND: Well, you really cannot see.
Nothing visible at all. Just stay in here for the day. MILES O’BRIEN: The team had to hunker down
for three days. The timing was not looking good. DAVID HOLLAND: If we don’t get the drilling
started tomorrow, then we run into a whole series of problems. Basically, there’s another
storm coming in about three days, but we need three days to get the drilling set up and
done. MILES O’BRIEN: But when the storm passed,
the good weather held, and things fell into place quickly. After 36 hours of hot water drilling, they
broke through the bottom of the ice to the ocean a half-mile beneath. They lowered in
a remotely operated vehicle called Icefin, which provided some unprecedented images of
the ice-covered shore of a glacier. Funded by NASA, the device was built by a
team from Georgia Tech led by astrobiologist Britney Schmidt. BRITNEY SCHMIDT, Georgia Tech University:
One of the things that we don’t know very well is exactly how glaciers move and how
the very base of the glacier operates. So, when we get to see it right up close,
right where it hits the ocean, we are seeing the freshest material. MILES O’BRIEN: They collected sediment cores
and dropped in instruments that measure water salinity, temperature and turbulence. It turns
out the water at this particular spot is very still. Aurora Basinski is a grad student at NYU. AURORA BASINSKI, Graduate Student: Since turbulence
is below detectable levels, that means there isn’t as much mixing as potentially we would
have expected. And so what that means is that the warm water is mostly staying near the
bottom, and not necessarily making its way up to the ice. MILES O’BRIEN: That might seem like good news,
but for the first time, scientists have confirmed what they suspected: The ocean under Thwaites
is warm, 3.6 degrees Fahrenheit above freezing, too warm for the ice to remain stable. It’s a sobering moment, too, isn’t it? DAVID HOLLAND: Yes. Yes. Change happens, and
this looks like a potential case for change going forward that could be quite impactful. You can probably change air temperature over
the next century, but the ocean is such a big, sluggish creature that, in a way, when
it’s doing what it’s doing, it’s not the kind of thing we can engineer and stop very easily. MILES O’BRIEN: Before they left, the team
buried five GPS stations across the grounding line. They will gather precise data about
the glacier’s movement and thickness over the long, dark winter. The MELT team plans to be back next year to
recover that data and do more science. They hope this risky work at the edge of possible
will help researchers make better forecast models, adding more facts to the growing fear. For the “PBS NewsHour,” I’m Miles O’Brien.

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