Geologist maps ancient ice to forecast climate shock

Allie Balter-Kennedy, a 34-year-old geology scientist at Tufts University, drills into Antarctica and Greenland’s ice to read Earth’s hidden history. Using cosmogenic-nuclide exposure dating, she measures isotopes created by cosmic rays to estimate when buried

For weeks at a time. Allie Balter-Kennedy lives on an ice sheet with nothing between her and the cold but a tent and the work that keeps her moving. The place is remote, harsh, and demanding—exactly the kind of environment she says she relishes. “The aspect of getting to be outside and work in remote places and the collaborative nature of all this fieldwork are essentially what drew me to this field in the first place. ” she explains.

At 34, Balter-Kennedy is a Tufts University scientist who studies how a warming climate will impact Earth’s ice sheets. She takes her questions to some of the planet’s most unforgiving locations. sometimes drilling hundreds of feet down into the ice. The samples she pulls up come from timelines that stretch far beyond any human memory—changes recorded over thousands. even millions of years.

In the cores, she’s looking for the moment the ice—and the land beneath it—last shifted, when it was effectively ice-free. That timing matters because it can reveal what climate processes were underway at the time, offering clues to how the system may behave as today’s warming continues.

To translate those buried layers into a workable timeline, Balter-Kennedy uses a method called cosmogenic-nuclide exposure dating. The approach takes advantage of the fact that Earth is constantly bombarded with cosmic rays made up of charged particles. Those particles interact with atoms in the atmosphere and at the planet’s surface, creating isotopes.

By measuring the levels of isotopes in long-buried core samples, scientists can estimate how long it’s been since that rock was exposed to the atmosphere. Knowing when the land was last ice-free helps scientists connect past conditions to the climate story the ice sheets are telling.

Balter-Kennedy’s research has also taken her to Antarctica and to the Arctic. including Greenland. where her fieldwork has a rhythm of isolation and teamwork. And when she returns from those extreme settings, the job changes shape. She is now getting a crash course in the administrative side of being an early-career academic—applying for grants. teaching undergraduates. and recruiting people to work in her laboratory.

The same drive that pulls her toward the ice cores also fuels her in the quieter parts of the work, where the questions are still the same: what climate change will bring, and what she may find in the depths of the planet’s ice.

In one sentence. her work traces a straight line from the atmosphere’s constant bombardment—charged particles turning into isotopes—to the cold archive of Antarctica and Greenland’s ice sheets. where those signals can be measured long after the surface has changed. The drilling. the isotope measurements. and the effort to reconstruct when rocks last saw the atmosphere all point toward a single goal: reading enough of Earth’s past to better anticipate the future of its ice.

This story is part of “The Young American Scientists,” an editorially independent project produced with financial support from Regeneron. Balter-Kennedy’s portrait and video interview were captured with special thanks to the Museum of Science in Boston.

climate change ice sheets geology Tufts University Antarctica Greenland cosmogenic-nuclide exposure dating cosmic rays isotopes isotopic dating