SOUND JOURNALISM ABOUT THE PLANET

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Richard Nunn and Curt La Bombard are curators at the National Science Foundation’s Ice Core Facility (NSF-ICF) in Lakewood, Colorado, which holds the largest archive of ice in the world—containing some 25,000 meters. | Credit: Frani Halperin/H2O Media, Ltd.

Frozen Assets—The Race Against Time to Protect Priceless Artifacts

We study history to learn from the past. But what if the pages in a history book melt away? A library just west of Denver is trying to preserve clues of antiquity before they become “cold cases” that could never be solved.

By Frani Halperin, Executive Producer
Published: 02 Feb 2024 | © H2O Media, Ltd.

Lakewood, Colorado—Looking for your next read? How about a mystery that delves into a past that perhaps no one has ever heard before. There’s a library that holds those stories—stories of how our planet might have looked hundreds of thousands of years ago before humans existed. You don’t need special permission to enter this library, but you will need a reservation—and a parka. It’s -40 degrees inside, where these books, so to speak, are kept.

Theo Carr guides visitors into the freezer at the National Science Foundation’s Ice Core Facility where samples are inventoried and stored. | Credit: Frani Halperin, H2O Media, Ltd.

Theo Carr is our “librarian” today as we enter the National Science Foundation’s Ice Core Facility (NSF-ICF) in Lakewood, Colorado, just west of Denver. The building holds the largest archive of ice in the world—containing some 25,000 meters—collected from the Arctic to Antarctica. Staff, like Carr are tasked with safely and securely storing ice cores from the glaciated regions of the world.

“Welcome to the freezer. It's made of basically four rooms,” Carr says as he guides a group of us, which includes climate science students from Colorado College, in Colorado Springs. Some giggle nervously at the prospect of walking into a freezer bigger than a basketball court.

We start our tour in the -26 degrees Celsius exam room, where newly arrived ice is unpacked and inventoried prior to being made available to researchers. Many scientists have already requested and anticipated their samples and will come to facility to inspect them and carve them into sections. A portion of each new arrival will be archived into the library of ice.

The exam room feels balmy compared to the -40-degree storage freezer, which houses the cores long term in metal cylinders. Once inside, we see row upon row of shelves holding the tubes, each containing a meter-long sample labeled with its origin and depth.

“Everything on my left here is the WAIS Divide project from West Antarctica,” Carr says, pointing to a cylinder labeled 2803, which corresponds to the depth under the surface. “So, if you're looking at this, this is two miles of ice.”

A Time Capsule

The ice took a long journey to arrive at the facility via plane, boat, and then 18-wheeler—but a much longer odyssey to form. Over thousands of years, season after season, when snowflakes fell, they carried with them snapshots of the conditions of their day—from the temperature and solar activity to the chemical makeup of the atmosphere.

Over time, those layers of snow compressed on top of each other to form ice, which since they were at the poles, were well preserved like pages in a history book, describing dust particles, temperature, sea spray, and the atmosphere. Buried potentially forever until the mid-1900s when ice core drilling began in earnest.

Some of the earliest drilling was a reaction to, coincidentally, the Cold War. The U.S. military established Camp Century in Greenland—ostensibly for scientific research but with a secret purpose to keep an eye on the Soviets.  

<p>A science technician measures a section of the WAIS Divide ice core as it begins its journey down a core processing line. Scientists and technicians will cut the ice so it can be sent to labs around the country for analysis.  | <em> Credit: Peter Rejcek, NSF</em></p>

“Camp Century was the first ice core ever drilled,” Carr explains. “We do have that core here. It was originally drilled as sort of a subsurface structural appraisal to make sure that missiles didn’t come over the poles.”

Nowadays, samples are drilled to understand how our climate has changed over millennia. A piece of ice that Carr just showed us is around 400,000 years old but a recent arrival tops that. “So, over there you can see some of our newer ice. This is the Allan Hills…instead of being 400,000 years old, is four million years old." He says that additional samples from Allan Hills are expected to arrive in late March.

Ice Is Nice, But Why Study It?

Scientists from research institutes across the country study ice cores. Some will look at air bubbles trapped in the ice to measure carbon dioxide or methane; some might analyze dust from ancient volcanic eruptions. Others, like Bruce Vaughn, will pick up the ice to study temperature records at his lab at the University of Colorado, Boulder, about a half hour away.

Bruce Vaughn, stable isotope lab manager at the University of Colorado, discusses a graph showing natural cycles of CO2 and temperature over time—and the sudden spike in CO2 during the modern era. | Credit: Frani Halperin, H2O Media, Ltd.

Vaughn, together with his research partner Valerie Morris, work at the Institute of Arctic and Alpine Research or INSTAAR, which studies the past, present, and future of Earth systems. The two have developed a system that uses water isotopes to determine what the temperature was when each layer of ice was formed. Isotopes are molecules that have the same number of protons and electrons, but a different number of neutrons, affecting their mass.

Vaughn says, for example, that water—H2O—has oxygen that has a molecular weight of either 16 or 18, making it a light or heavy water. Most of the water vapor in the atmosphere comes from the ocean around the equator. As clouds move toward the poles, heavier water tends to precipitate first, leaving the isotopically lighter water to fall in colder regions, which allows Vaughn to correlate ratios of isotopes in ice cores, and infer the temperature from when the water fell as snow.

They can then compare their data with researchers studying climatic records of gases, such as methane and carbon dioxide, to see how global temperature and greenhouse gases are related.

One thing abundantly clear—the acceleration we’ve seen since the Industrial Revolution is abnormal. Vaughn explains that temperature along with carbon dioxide levels have naturally fluctuated over Earth’s history in cycles lasting between 44,000 to 100,000 years. “For the last million years, CO2 in the atmosphere has never really gone, despite its ups and downs, never gone above maybe 280 parts per million.”

Until now. As of January 2024, the amount of heat-trapping carbon dioxide in the atmosphere is a whopping 422 ppm. And it happened rapidly, not in the rolling epochs of the past. We just don’t know how the planet will respond to such a jolt.

“I'm at the end of my 60s. We've had a wonderful party with fossil fuels for a couple of centuries—at a cost that’s now only becoming evident. And so, it’s as if we’ve had a really good time and we’re leaving them to clean up the party.”

“Them” are future scientists like the college students on the ice facility tour who will likely be the ones mopping up the mess, using ice data to try to predict Earth's reaction and how we can prepare.

There’s urgency to this work. Earth’s ice history book is melting away, leaving torn pages, rearranged ones, or none to work with at all. Recent research showed that the Greenland ice sheet is melting faster than previously thought, and Vaughn says, the Arctic is heating up more rapidly than anywhere on the planet. Meanwhile, we’re writing the next chapter of this epic. Whether it will be inscribed in ice for future generations to read, will depend on the choices we make today. 💧