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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Wedged between East and West Antarctica and fed by glaciers from both parts of the continent, the Ross juts up at the sea’s edge in sheer white cliffs 160 feet high. It was discovered by James Clark Ross, a British polar explorer, in 1841, and has since served as a base of operations for landmark expeditions to the continental interior. Now it’s the focus of a multi-institutional mapping project called Rosetta, after the stone slab that led to the decoding of Egyptian hieroglyphics. The effort, headed by Bell, examines the interactions between the ice, the earth, and the ocean, and how the shape of the bedrock beneath the ice influences ocean currents.

“The Ross ice shelf is particularly sensitive,” Bell says, “because its bottom is exposed to ocean. Warm water gets underneath the ice. We’re figuring out the pathways that the water takes to get in.” The Ross, then, is vulnerable from above — in January 2016, unusually warm winds caused extensive surface melting — and below.

That worries Bell.

“We think the shelf is under stress,” she says.

To investigate, Bell and her team deploy a custom-made device called IcePod — an eight-and-a-half-foot-long instrument-filled fiberglass capsule that attaches to the LC-130 transport planes that take Lamont researchers to the ice sheets. Designed and built with grant money from the National Science Foundation (NSF), IcePod is rigged with conventional and infrared cameras adapted for ice use by Lamont oceanographer Chris Zappa ’92SEAS (the infrared cameras can detect unseen cracks, or crevasses, by measuring tiny variances in ground temperature); shallow- and deep-ice radar built by Nick Frearson, IcePod’s lead engineer; a scanning laser to create 3D images of the ice surface; and a magnetometer to measure the earth’s magnetic field.

The radar images capture jagged cross sections of the Ross ice in shades of MRI gray, revealing what Bell calls “the beautiful layers inside.”

Decoding the mysteries of the Ross ice shelf — to see where it’s melting — is no fly-by-night affair. Last year’s trip was hampered by bad weather, and the team could not finish the study. “While we can tell where it’s melting in the front of the ice shelf, we still don’t know what’s going on in the back,” Bell says. She hopes that the NSF will support another trip in order to complete this benchmark data set.

“Where we’re working now, the last time they collected data was in the 1970s. That data is plugged into every ice-sheet model predicting what’s going to happen in the future. To still be using data from almost fifty years ago is just stunning, so we’re hoping to improve that.” Bell smiles, acknowledging the scope of the enterprise. “We’re trying,” she says, “to understand the basic topography of the earth.”

The Case of the Blue Dots

Seven years ago, Jonathan Kingslake, now a Lamont glaciologist, was working on his PhD at the University of Sheffield, in the UK. In his thesis he used mathematical models to examine how water moves underneath the ice sheets.

In the course of this research, Kingslake got to thinking — “just for fun,” he says — about surface water. He went on Google Earth, zoomed in on Greenland, and noticed something in the field of white: blue dots, speckling the rim of the ice.

He saw them in Antarctica, too: Windex-blue flecks of liquid water. Scientists know that if meltwater collects around the edge of the ice sheets and on the ice shelves, it can spell trouble, as water can seep into crevasses, forcing the ice apart, weakening the entire edifice. In 2002, satellite images showed that the Larsen B ice shelf on the Antarctic Peninsula, before its famously rapid and spectacular collapse, was stippled with blue dots. (This summer, the Larsen C ice shelf made news when it calved a Delaware-size iceberg.)

Kingslake wondered about the rest of Antarctica. No one had ever surveyed the 5.4-million-square-mile, ice-covered continent for surface water. Kingslake thought he might look into it someday.

In 2016, Kingslake came to Columbia as an assistant professor in the Department of Earth and Environmental Sciences. He hadn’t forgotten those blue dots. At Lamont he promptly led the first-ever systematic study of surface hydrology on the Antarctic ice sheet. Using images taken from military aircraft since 1947, and from satellites since 1973, Kingslake, with Lamont colleagues Bell and Indrani Das, as well as Jeremy Ely of the University of Sheffield geography department, revealed a world of unsuspected complexity. Far from a white blanket dappled with in situ pools of water, they found surfaces veined and braided with networks of waterways carrying meltwater across the ice sheet: continent-wide seasonal drainage systems of some seven hundred streams, rivers, ponds, and waterfalls.

Kingslake knew they’d found something important. “Amazingly, people weren’t really aware that there’s surface water being moved across long distances on the ice sheet,” he says. “These systems are very impressive, very large” — one pond was fifty miles long — “and much more widespread than we would have thought.”

This past April, Kingslake and his colleagues published their findings in Nature. They hypothesized that these drainage networks could deliver water to areas of ice shelves vulnerable to collapse — thus accelerating ice-mass loss in Antarctica.

The Adventure of the Melting Island

Greenland is the biggest island on the map, three times the size of Texas and more than three-quarters covered by ice. This ice sheet — the second largest on earth, flung over the Arctic landmass like a white bear rug — is pulling a monumental disappearing act: little by little, year by year, a little faster now, slowly giving ground.

As the glaciers retreat, Marco Tedesco pursues. Tedesco, a Lamont polar scientist, wants to know how much mass Greenland is losing, and by what processes — how much from ice flow into the ocean, or the calving of icebergs, or — the primary culprit now — surface meltwater.

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ICE DETECTIVES

The Ice Detectives by Paul Hund (Columbia Magazine, Fall 2017) describes how leading polar investigator Robin Bell (‘89GSAS, geophysicist at Columbia’s Lamont-Doherty Earth Observatory), and other distinguished Columbia polar scientists, have been building our observed scientific knowledge about the unexpected complexity of Antarctic and Greenland ice sheets, a critically important part of our "planet yet to be explored and understood” according to Bell.

Comments attributed to the Columbia scientists leave little doubt that their open minds, in the tradition of Galileo and Kepler, are making detailed studies based on their own quantitatively precise observations, following Francis Bacon’s revolutionary idea that to understand the world we must study the world, instead of relying on sacred consensus.

Regrettably the article is sprinkled with distracting random climate alarmist jargon unrelated to the primary research described. Why is it necessary to mention the thoroughly discredited projection of 8.2 feet of sea level rise by the end of the century (= 30.1mm/year)? This editorial insert starkly contrasts with Bell's lucid statement about future sea level rise, “My belief is that we don’t know yet.” Elsewhere in the article the scientists say historic and current sea level rise is between 2.5 and 3.2 mm/year vs the editorially inserted alarmist projection of over 10 times that rate.

Similarly the author uses the non-science word “consensus” as evidence that CO2 is the “…main driver of warming” and “caused unusual weather events.” Unambiguously Earth’s CO2 atmosphere concentration has increased dramatically since 1897. But equally unambiguously primary data from NASA's satellite measurements of global average surface temperature shows no statistically relevant global temperature increase in 18 years. Likewise for 100 years there has been no statistically significant increase in extreme weather events (frequency has declined) . While correlation does not prove causality, lack of correlation disproves it.

Hats off the Columbia scientists for important, extensive primary polar research. Columbia Magazine should not, however, contaminate objective information with editorial bias.

Peter Spiller, SIPA 1968
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