COVER STORY

The Ice Detectives

Columbia researchers go to the ends of the earth to crack the coldest case of all.

by Paul Hond Published Fall 2017
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Fifty years after the IGY, Bell jointly helped revive its long-defunct forebear, the International Polar Year (the first was in 1882–83; this was the fourth). Bell’s team from seven nations set out to study an area of Antarctica the size of California — including the Gamburtsev Mountains. Understanding how the mountains formed would give the scientists important data for ice-sheet and climate models, and help them scout the best places to drill for cores. These invisible peaks were the ice sheet’s birthplace, the point from which the ice grew and spread. The ice’s oldest climate record could be here.

Bell and her partners flew laps over the white fields of East Antarctica in two Twin Otter airplanes outfitted with deep-ice radar, magnetometers, and gravity meters to penetrate the secrets of the ice-entombed “ghost mountains.” It was in the course of these investigations that Bell and her team made their own startling discoveries.

“It’s like learning about a new piece of plumbing in your house.”

Radar indicated that there was liquid water in every valley, running under the ice. The researchers expected that the water, warmed by the earth’s heat, would thaw the bottom of the valley ice, which was already close to melting temperature. (The top of the ice is around -50°F.) But the water did something unexpected.

“What’s beautiful,” Bell says, “is that we saw that water is being driven uphill.”

It was one of nature’s freak occurrences: due to the position and pressure of the ice, the water was being squeezed backward and upward. Even more astonishingly, this gravity-defying water, forced up the mountainsides to colder zones, was freezing back onto the bottom of the ice sheet, in accretions hundreds of feet thick. That meant that part of the ice sheet was growing faster from below than from above.

“Jaw-dropping” was how Bell described the discovery. Her colleagues gasped when they saw the data. “It’s like learning about a new piece of plumbing in your house,” Bell says. “Learning a new way that water can move around.” And while no one knew at the time that these processes could be important — “the Gamburtsevs are really in the middle of nowhere, far from anywhere that the ice sheet is changing,” Bell says — the same phenomenon has since been detected in Greenland.

Bell is encouraged by these findings — not because ice can form in surprising places, but because we’ve added to our understanding. “We are learning better how our planet is changing and how it will change in the future,” she says. “Our new knowledge provides us hope.”

The Big Drain

The Nansen ice shelf, a 695-square-mile nugget abutting the Southern, or Antarctic, Ocean, is a floating curiosity: despite evidence of widespread surface water, the Nansen is apparently stable. Why?

In April, Bell, with a team that included Lamont scientists Kingslake, Tedesco, Das, Kirsty Tinto, Zappa, Winnie Chu, and Alexandra Boghosian ’17GSAS, published a companion paper to the Kingslake-led study on the possible dangers of meltwater transport. Both papers appeared in the same issue of Nature.

The Bell-led inquiry revealed another facet of the secret life of ice. Using satellite and aerial photography, radar data, and archival journals and photographs from Britain’s Northern Party expedition of 1910–1913, the researchers found that the Nansen ice shelf possessed networks of streams, ponds, and rivers that converged, near the shelf’s edge, in a spectacular 425-foot-wide waterfall.

The waterfall, they discovered, was capable of draining the shelf’s annual surface melt in a week. This meant that surface rivers don’t just transport water to other areas of the ice, exacerbating melting; they can wash standing water off the ice, potentially preventing this destruction.

Found to be active for more than a century, the Nansen drainage system adds a twist to existing Antarctic ice-sheet models. The variations complicate the question of the overall impact of water on the ice sheet.

“Will these drainage systems move water into places that are more vulnerable, or will they remove water from those areas?” Kingslake says.

He answers his question with perfect scientific equanimity, in words that resound through the great and howling icescapes of the world:

“We don’t know yet.”

Ice Dreams

Robin Bell has a vision. She wants investigators to fly all the way around Antarctica so that they can figure out the thickness of the ice that extends into the ocean, and find the troughs in the sea-floor bottom that funnel warm water. “If we can understand how and where the warming ocean is reaching the edge of the ice sheet,” she says, “we can better predict how much sea level will go up in the future.”

Though the climate for NSF global-warming research has cooled, Bell, who this year became president-elect of the American Geophysical Union, puts stock in America’s traditional leadership role in polar science, to which her ten expeditions attest. “We’re lucky to have really good support as a nation for Antarctic science,” she says.

But even in the most favorable conditions, there are never any guarantees.

Each expedition is “an incredibly pressure-filled, unique opportunity,” Bell says. “It often involves going to a place where nobody’s been for decades — and if you screw up, nobody might get to go again.” She thinks of the astronauts who went to the moon, and how no one has gone back since 1972. It’s a similar feeling, going to the ends of the earth.

“You’re trying to keep everyone together and everyone safe, and trying to squeeze every last bit you can out of the expedition, because you don’t know if or when you’ll get back,” she says.

And all the while, the ice keeps moving, changing, slipping, and sliding; and the ice detectives, in the field and at their desks, continue their restless surveillance, knowing that the clues they find today will have a life beyond their own: another layer in the frozen record, to be studied by future scientists.

“When you collect data, you might not even know the right questions to ask of it,” Bell says. “It’s going to be a legacy.”

 

RESOURCE GUIDE
Learn more about the Columbia Commitment to Climate Response at http://commitment.columbia.edu/climate.

The New York Times has produced an in-depth, multimedia series, "Antarctic Dispatches," highlighting the work of Lamont scientists in Antarctica.  See it here: https://www.nytimes.com/interactive/2017/05/18/climate/antarctica-ice-melt-climate-change.html?_r=0

Stay up-to-date on the latest research and discoveries at



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