Paul Bierman Discusses His Book 'When the Ice Is Gone'

University of Vermont geologist Paul Bierman in his lab on campus Credit: File: Bear Cieri

In the prehistoric past, Greenland was green. Paul Bierman, an environmental science professor in the University of Vermont’s Rubenstein School of Environment and Natural Resources, can now say with confidence that this was true about 418,000 years ago — more recently than the millions of years ago researchers had thought.

Bierman calls that discovery his only “Eureka!” moment in a 40-year career. And he would never have made it without the Cold War-era researchers who spent years living and working year-round in a city buried deep inside the Greenland ice sheet.

In the 1960s, when Bierman was a child, hundreds of men drilled nearly a mile through the Arctic ice and into the frozen sediment below to extract core samples for study. Decades later, Bierman and his team used those samples, and nearly $3 million in National Science Foundation grants, to prove not only that Greenland was once a verdant landscape but that the ice sheet is more vulnerable to human-induced climate change than anyone suspected. Its disappearance, which could happen again by century’s end, would have dire consequences for the more than 3 billion people in the world who live along a seacoast.

Bierman, 63, offers his findings to a general audience in When the Ice Is Gone: What a Greenland Ice Core Reveals About Earth’s Tumultuous History and Perilous Future. Equal parts climate science, history lesson and cautionary tale, the book tells the story of Camp Century, a subsurface U.S. military base originally conceived to deter a Soviet attack over the North Pole.

But the military soon realized that even mile-thick Arctic ice is not a stable environment. The polar outpost was abandoned in 1967, and many of its precious core samples, rarer even than moon rocks, were lost — or so scientists long believed.

When the Ice Is Gone recounts how those core samples were discovered decades later in a Denmark freezer and revealed to contain plant particles hundreds of thousands of years old. Using repurposed particle accelerators from the 1960s to count ultra-rare radioactive isotopes, researchers pinpointed the age of those fossils, which were too old to carbon date.

A fascinating and easily accessible read, When the Ice Is Gone has attracted considered press attention since its release in August. In part, that’s because the book is free of scientific jargon and a political agenda — beyond sounding the alarm about an imminent catastrophic sea level rise.

“We can learn so much from ice cores.” Paul Bierman

Bierman, the subject of an October 11, 2023, cover story in this paper called “On Thin Ice,” spoke to Seven Days recently about his book and the public’s reaction to it.

Did your book generate much pushback from climate-change deniers?

I have not had any hard-core climate-change denial. I’ve published papers before where I got that kind of stuff, but nothing from this. But the book isn’t set up that way.

I didn’t want to write a “red” or “blue” or “liberal” or “conservative” book on climate change. I specifically emphasized the role of the U.S. military in the earliest research into climate change, and I think that broadens the book’s appeal. I’ve probably gotten a half-dozen emails from people, some of whom worked in Greenland, some who were in the military or worked for the Army Corps of Engineers, who really appreciated it.

I found it interesting that Camp Century’s mission was primarily military, with the scientific research being somewhat secondary. Yet it was the research that proved the most enduring and valuable.

I’ll take a small issue with your leading statement. Camp Century was definitely military, but the military was heavily invested in scientists who were trying to understand the cryosphere [the frozen parts of Earth that include snow, ice and permanently frozen ground]. Obviously, the military was invested mostly for operational reasons, to understand how snow behaves and how it changes with temperature. You can’t run military vehicles reliably across the ice sheet, and you can’t fight in Arctic theaters. It was a military-forward base, but they did so much fundamental engineering research at Camp Century, too.

I feel strongly that this was [Swiss scientist] Henri Bader and his influence on the development of the science from 1947 through the mid-1960s. He was the one who talked the Army brass into caring about the fundamental research and then paying for it. So I put a lot of this on one man’s vision to talk the Army into spending six years drilling a hole and studying the basic physics of snow and ice. Without him, this project wouldn’t have happened.

So Camp Century’s original goal wasn’t to do scientific research but to further the ability of the U.S. military to operate in a harsh Arctic environment and deter the Soviets?

That’s completely right. Their goal was to fortify Greenland and have outposts there and show the Soviets that we’ve got missiles and soldiers and planes that we can deliver over the top [of the world]. But to do that, the Army realized they first had to understand the theater they were operating in.

I don’t think it’s a lot different today, when the military is very aware of climate change and its strategic implications [for] ensuring that their mission goes on.

What came out of Camp Century that lasted wasn’t the ability to put a base inside an ice sheet. It was this ice core, as well as the knowledge of snow and ice that came from the people who worked there for 20 years.

Has your research, and the press coverage of it, sparked a deeper interest in polar science generally?

When the Ice Is Gone: What a Greenland Ice Core Reveals About Earth’s Tumultuous History and Perilous Future, W.W. Norton, 304 pages. $27.99 hardcover, $18.99 paperback. Credit: Courtesy

I think so. There’s a lot more talk about it and a lot more people jumping on the “Hey, what’s under the ice?” bandwagon … to look at this really important and detailed sediment record under the ice sheet.

The ice is really useful. We can learn so much from ice cores. But it’s time-limited, because the ice in Greenland isn’t very old. The oldest is about 125,000 years old. But with the sediment, we have information going back about 400,000 years, and potentially back to the beginning of the ice sheets 2.7 million or more years ago.

Was it at all fortuitous that you made this discovery relatively late in your career?

This project never would have been as successful if I had done this as a junior faculty member rather than when I had 30 years under my belt, because I know so much more now about glaciers and fossils and how sediment systems work. It was a stroke of luck that it landed on me when I was more experienced.

Glacier archaeologists are racing to recover and document human artifacts that are emerging from polar ice for fear that they’ll disintegrate once they’re exposed to the elements. Is there a similar concern in your field?

Absolutely. Lonnie Thompson at Ohio State University has been coring ice in the tropics, on glaciers that are clinging to the tops of very high mountains. Many of the glaciers he cored 25 to 30 years ago are now gone due to climate change. In the 1970s, people looked at his [National Science Foundation] proposals and said that not only would he fail but he would die doing it. But he didn’t die, nor did he fail. He opened up a window. Now, there are glaciers for which the only ice we have [is] in the freezers at Ohio State.

Has your work attracted more applicants to your program at UVM?

Yes, which is a little ironic because the grant is in the wrap-up phase right now. But the thing that I’m most excited about is the breadth of people who seem to be interested in the book. It’s not just scientists. It’s not just historians. I’ve gotten so many emails out of the blue from people who said, “I read your book. This is so fascinating.” That makes me feel really good, because my goal was to reach a broader audience.

This interview was edited and condensed for clarity and length.

From When the Ice Is Gone

Snow is exquisitely frozen water. Every marvelous crystal is unique. It’s fragile, intriguing stuff that falls from the sky in all sorts of shapes and sizes. Snow also carries memories of when and where it crystallized high in the atmosphere. The frozen molecules of water record, in the isotopic composition of each of their oxygen and hydrogen atoms, how cold the air was when they froze and where the air came from. At birth, snowflakes wrap themselves around tiny bits of earth and sea suspended in the atmosphere. Locked to these condensation nuclei, they begin a trip from the clouds to Earth’s surface. If a snowflake lands on an ice sheet, its journey back to the ocean and the atmosphere could take thousands, even millions, of years. …

Camp Century was truly a city under the ice. As a military base inside an ice sheet, the camp was a unique outpost of humanity in what many have described as a featureless icescape without end. Over a hundred men lived there isolated for months at a time under the snow, cut off from the world by blizzards, magnetic storms, frigid temperatures, and howling winds. Jon Fresch, an Army photographer who first went to Greenland when he was eighteen years old, described living at Camp Century this way when we talked: “I liken it maybe to being on a submarine because once you went down, for the most part, unless you had a job that took you above ground or onto the surface, you had no reason to be up there because when it stormed it stormed, and you didn’t want to get lost, that’s for sure.” …

Those investigating the science of climate change in 1958 were like early adolescents, curious but confused. People like Maynard Miller wondered why many Alaskan glaciers were retreating, and the military was worried about its Arctic operations should polar ice begin to melt. Some thought that Earth was getting warmer, but there was no agreement on why, how much, or what drove the warming. …

Ice is by nature fragile, and as Earth warms, our library of climate history is flowing away in murky streams of glacial meltwater and into the world’s oceans. Soon, racks of cores checked out from Farrier’s ice-sheet libraries may be all we have left, analogous to the surviving fragments of Greek tragedies from the Library of Alexandria, incomplete but tantalizing reflections of their playwrights’ greatness.

The original print version of this article was headlined “Hot Topic | UVM’s Paul Bierman drills deep into the history of climate change research in When the Ice Is Gone“