Buried in Snow
UMD Researchers Hunt for Hidden Water in Greenland’s Vast Ice Expanse
Lynn Montgomery ’16 had never even gone camping before last year, when she caught a helicopter to a barren glacier in Greenland to study the effects of global warming, coping all the while with the possibility of prowling polar bears and 15-foot snowfalls.
“We’re out on the ice sheet about 18 days to finish everything we need to do,” the former atmospheric and oceanic sciences major says. “Doing that was a pretty big leap for me.”
She was assisting Nicholas Schmerr, an assistant professor of geology studying Greenland’s “firn”—a thick layer of packed snow that coats ice sheets. The formation caught the attention of global climate watchers earlier this decade when Schmerr’s collaborators from several universities described new subsurface lakes known as “firn aquifers” in areas that large-scale melting hadn’t been seen before.
“The consensus is that climate change is probably 100 percent responsible,” he says.
Schmerr is using seismology to measure an aquifer’s shape. With Montgomery’s help, he extended strings of sensors across the ice, and then bashed a metal plate with a sledgehammer. The sensors picked up the vibrations and gave a partial view of what lies beneath, helping to answer some fundamental questions.
“Does the water drain to the bed of the ice sheet, or is it finding another pathway through the ice that we’re not aware of, or is just being stored there—perhaps growing in volume each year?” says Schmerr, who returned to Greenland this summer for more experiments.
Greenland’s ice is closely linked to climate and coastlines. While Schmerr says emptying the Greenland firn aquifer into the oceans would raise the global sea level by only a millimeter (at a time when it’s already rising 1.8 millimeters a year), the entire island’s ice, if melted, could boost it by 7 meters.
Though most scientists consider that highly unlikely anytime soon, a far more modest melt still could impact global climate if enough freshwater pours into the North Atlantic to affect ocean currents.
Montgomery, meanwhile, plans to continue as a graduate student at Colorado, where one of Schmerr’s colleagues on the Greenland study, Lora Koenig, is a researcher at the National Snow and Ice Data Center.
“It was one of the most fantastic experiences of my life,” she says. “I’m definitely hoping to go back to Greenland.”
Photos courtesy of Derrick Lampkin and Lynn Montgomery
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Terp Researcher Keeps Eye on “Runaway” Glacier Flow
Warmer ocean water is nibbling away Greenland’s ice sheet at the edges, speeding up the rate it ends up in the ocean, says another Greenland-focused Terp researcher.
“I have been to both Antarctica and Greenland on several expeditions over the last 20 years, and Greenland is a runaway train of ice,” says Derrick Lampkin, assistant professor of atmospheric and oceanic sciences.
Greenland loses mass mainly through large fast-flowing glaciers—or “ice streams”—that transport ice from the interior to the ocean.
Lampkin works at the coastline, where glaciers calve off mass to form icebergs, examining how warmer water on the surface seeps down to speed the journey toward the sea.
“What happens when you get that water on top of the glacier down inside—what does it do to the glacier’s ability to flow?” he says.
Computer modelers and scientists collecting data in the field are trying to understand all the factors behind climate change-driven melting of Greenland, he says.
Lampkin’s work from satellite observations and modeling shows that it doesn’t take an injection of much water at all to pull ice more quickly through the ice streams and into the sea. As Greenland gets warmer, he says, the impact of liquid water on glaciers could speed the glaciers dramatically—“like a car without brakes.”