Geologist preserves the cold truth of Earth’s past

This story appears in the fall 2025 issue of MSU Denver Magazine.

At the National Science Foundation’s Ice Core Facility in Lakewood, the freezer always wins. At least, that’s the adage Richard Nunn lives by. As assistant curator of the facility, Nunn often works in its subzero freezers maintaining an astonishing collection of ice cores — slices of the past that put his body and brain to the test.

In the frozen depths of the facility, Nunn, a 2010 Geology graduate of Metropolitan State University of Denver, takes care of some of the world’s most informative and precious sources of scientific data. During long days in the deep freeze of 11 below zero, Nunn wears layers of winter gear, takes breaks to warm his hands and eats more calories than normal, thanks to the freezer’s effect on his metabolism. All the while, his charges — frozen witnesses to passage of time so vast it’s hard to envision — surround him, meticulously cataloged and kept in ideal storage conditions.

“It’s the largest collection of ice cores in the world,” said Nunn. Handling the frozen material is only the tip of the, well, iceberg. Nunn manages a database of samples, processes new ice from the field, distributes samples to researchers and helps with on-site research.

“There really is no average day,” he said.

For decades, scientists have drilled ice cores from the glaciers and ice sheets in polar regions; the facility’s cores come from Greenland, Antarctica and North America. Ice cores act as a kind of time capsule for the paleoclimate — the climate of the ancient past — trapping the atmosphere in air bubbles that are buried in the ice by centuries of compacting snow and, sometimes, volcanic ash or dust.

“It’s the only source on the planet (for) a direct measurement of what our atmosphere was composed of tens of thousands or hundreds of thousands of years ago,” said Nunn. By preserving evidence of ancient temperatures and greenhouse gases, ice cores reveal how the planet has changed. Researchers date the ice cores and use them to re-create what the planet’s climate looked like at different points.

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We can use that data to inform ourselves about what’s happening now that humans have pumped a lot of carbon into the atmosphere, said Nunn. Postindustrial ice cores show quicker, more drastic change, he said — a warning as humans approach critical climate tipping points. “Things are changing way faster than should happen naturally,” he said.

Nunn’s daily duties change too, alongside research schedules. But, he says, his MSU Denver bachelor’s degree in Geology, which he earned in 2010, has served him well. “I had some of the best professors,” he recalled.

Nunn transferred knowledge gained as a Geology major to layered matter much colder than the slabs of rock he had become familiar with as a geologist. “I have a really wonderful spot in my heart for MSU Denver,” he said.

Nunn has formed friendships and connections with scientists around the world, and he feels the weight of his chilly task.

“Every once in a while, I realize I am storing and maintaining ice that predates humanity,” he said.  “Not just civilization but us as a species.”

If all goes as planned, these samples will serve as critical reference points for climate scientists for generations to come. And future researchers will have Nunn and his colleagues to thank for keeping these important scientific sentinels safe.

Learn more about the Applied Geology program at MSU Denver.