Coring for climate clues in Antarctica

West Antarctica’s Thwaites glacier is melting. That is worrisome, because buried deep in its ice lie vital clues to past climate conditions.

But there’s another reason, given the destructive rises in sea level that are in store as polar ice melts.

“As a glaciology community, if there’s one glacier we’re most worried about on the planet, it’s Thwaites glacier, which is about the area of the state of Florida,” says Peter Neff, a polar glaciologist in the University of Minnesota’s Department of Soil, Water, and Climate. And that glacier is melting fast.

In his research, Neff examines ice cores to read the records of past climate conditions. This data can help predict how global warming will affect rises in sea level and other aspects of our current environment. Gathering it involves being flown by helicopter from an icebreaker to the work site, which is otherwise unreachable.

Neff speculates that relatively warm water is getting beneath the floating extension of the glacier—the ice shelf—that is cantilevered out over the sea. If gaps form where the glacier rests on land, warmer water can seep underneath the ice shelf and accelerate melting.

“The ice shelves are sort of the corks in the bottles that hold back the ice upstream,” Neff explains. “If the retreat continues, we won’t see the glaciers stabilize and regrow.” At that point, he says, sea levels will rise.

Meltwater from West Antarctica could raise sea levels by perhaps 10 meters by the year 2300, swamping global shorelines and flooding a third of Florida. “It’s one of the tipping points we’re worried about,” Neff says.

Data from the Antarctic ice cores his team collects will help scientists reconstruct climates of the last 100 to 200 years at a resolution of one year. But a trip in January 2024 became a case study in how much can go wrong in collecting those cores and what it takes to rescue a mission.

Generating trouble

Neff and his team take their cores with a generator-powered drill. On this trip, both the main and backup generators malfunctioned shortly before the team was due to be helicoptered off the glacier.

But thanks to a Starlink connection, Neff and his team—doctoral student Julia Andreasen and engineer Etienne Gros—managed to find repair videos, fix a generator’s throttle, and extract the last ice cores on their agenda.

Flat, white, and treacherous

“As someone who has stared at imagery of Antarctica for years, it was surreal to finally be put into that context,” Andreasen says. “Once you’re there for the first time, with nothing around you and flat white as far as you can see, you’re very aware of how remote you are.”

Then came the storm.

The team had scarcely set up their tents before a massive ice storm devastated their camp. Andreasen was trapped in her tent when the nook she had carved from the snow collapsed and blocked the entryway. Luckily, says Neff, "Snow is very porous in the dry Antarctic, so even if your tent were totally buried—it's happened to me—you can still breathe."

Andreasen's colleagues cleared the entryway as soon as it was safe. 

“I should have slept with a shovel,” she observes. “And 24 hours in a tent gives you a lot of time for self-reflection.”

When the storm cleared, the team rushed to set up their coring drill—including a 25-foot tower—and enclose the work area under a high tent. On the final science day, they drilled to their target depth of 150 meters, packed their samples, and broke camp just in time to greet the helicopter arriving to fly them out.

Shipping the ice cores to their final storage location in South Korea took months, and getting to the point of harvesting the first data from them takes more months. But it took Neff virtually no time to start looking for his next voyage to Antarctica.

This work was funded by the US National Science Foundation and the Korea Polar Research Institute.

This story is adapted from an article in Minnesota Alumni magazine.