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Ice lab gets to the core of the climate crisis

‘The ice cores are the best record that we have of natural climate change’

Richard Nunn, assistant curator at the National Science Foundation Ice Core Facility, with an ice core sample.
Richard Nunn, assistant curator at the National Science Foundation Ice Core Facility, with an ice core sample. (Benjamin J. Hulac/CQ Roll Call)

LAKEWOOD, Colo. — Princess Elsa isn’t moving. Maybe because she’s inanimate. Or she takes her role in Disney’s movie “Frozen” too literally. The fact she’s a cutout could explain it. 

Or maybe it’s because Elsa, stored in the nation’s premier ice core laboratory, a freezer that holds more than 22,000 meters worth of core samples, lives in a room kept at -36 C. 

“The ice cores are the best record that we have of natural climate change,” Richard Nunn, assistant curator at the National Science Foundation Ice Core Facility, said during a recent visit. “To the best of my knowledge, this is the largest single collection of ice cores in the world.”

As humans perilously warm Earth by burning fossil fuels, the laboratory Nunn helps run is a hub for climate research, dispatching ice core samples by mail to scientists who request them, anchoring polar research for the U.S. and serving as a bulwark against climate denial.

For recent climate data, researchers lean on samples of air taken at sites like Mauna Loa Observatory in Hawaii. But those data only go back decades. To understand how the planet’s climate has changed over hundreds of thousands or millions of years, or to make climate predictions, scientists input ice core data into computer models.

Top climate research like reports from the Intergovernmental Panel on Climate Change, a United Nations-backed body, can often be traced back to the lab here.

“Ice cores are one of the best archives that the Earth provides, like a gigantic Library of Congress filled with important information,” Bess Koffman, a geology professor at Colby College, said by phone. “It takes dedicated work to read through those pages and figure out what the important stories are.” 

The “fundamental story,” she said, is how quickly humans are warming the planet. “By studying these archives, we see that the rate of change that humans are enacting on the environment is faster than anything that we see in the geological record.”

Ice cores will underpin climate research for years to come, Brenda Ekwurzel, a climate scientist with the Union of Concerned Scientists, said in an interview. “People are going to ask different questions in the future, and these cores are going to be there to answer those questions,” she said. “Basically, it’s like gold. It’s priceless.” 

Established in 1993, the laboratory gets funding from the National Science Foundation. The U.S. Geological Survey runs it. The site has multiple power backup systems in case the electricity goes out.

Outside the inner freezer is a second room, held at a comparatively balmy -24 C. There, researchers can run tests on the cores, which are stored in meter-long tubes in rows of racks, or prepare them to be shipped to scientists across the country or abroad.

Global samples

The site holds cores from Antarctica, Greenland and northern Canada. A smaller facility at Ohio State University holds some cores from alpine glaciers. Drilling an ice core, a process that can plunge miles deep, can take years, though the crews would only be on site for a fraction of that time.

“The deepest core that we have is the Vostok ice core, which is 3,600 meters deep,” Nunn said. “That one was drilled back in the mid-90s as a joint effort between the United States, France and Russia.” Vostok was drilled in Antarctica. “That’s the oldest continuous core in our collection. It dates back about 420,000 years.”

Paul Cutler, program director in Antarctic science at the National Science Foundation, said in an interview that a larger freezer for the lab is scheduled to start operating in 2025, part of an effort to contain the ever-growing collection. 

“It supports projects across the globe,” Cutler said of the lab. While the majority of researchers who request ice cores are focused on some aspects of climate science, the cores provide snapshots of what was happening eons ago by trapping bubbles and particles from the atmosphere.

When fires broke out, ash fell or volcanoes erupted in, say, ancient Rome, it becomes clear in the cross sections of the ice. 

For a recent paper, Koffman requested a sample to pinpoint the origin of pollution in Denali National Park in Alaska. “We were able to figure out that a really large proportion of the pollution was coming from China,” she said. 

The Biden administration has shown interest in polar science and geopolitics. President Joe Biden nominated Mike Sfraga, a scientist with the University of Alaska, Fairbanks, to be the nation’s first ambassador-at-large to the Arctic – a role the White House established. 

In the northern hemisphere, the Arctic is melting faster than any other region on the planet, and the White House said in a regional strategy plan released in the fall that it is poised for competition from Russia and China.

Growing interest comes as Antarctic sea ice hit a record low coverage this month, according to the National Snow and Ice Data Center.

Ancient ice

The mission of a federally backed project called COLDEX, the Center for Oldest Ice Exploration, is to extend the record of continuous ice core data going back to a minimum of 1.5 million years ago. Australia and a European consortium have similar projects.

“The key relationship is CO2 and temperature,”  Peter Neff, a University of Minnesota glaciologist working on the project, said by phone, using the shorthand for carbon dioxide, a greenhouse gas. “We know naturally in the past that it’s lockstep, it’s always been lockstep with temperatures,” said Neff, who was in Antarctica in January.

“We want to see more examples of natural warming and cooling to see if there’s ever any decoupling between CO2 and temperature, especially because as you push back further in time beyond 800,000 years, the trend is actually warmer and warmer in the past, and warmth that’s on par with with the work that we are heading towards.” 

Said Ed Brook, director of COLDEX: “We want to understand how the cycles of the climate, back and forth, changed back in time.”

The projects from other nations in pursuit of the world’s oldest ice is vital, Brook said in an interview. 

“There is precedent for drilling down to the bottom of an ice sheet and thinking that you found one thing and then realizing later he found another,” Brook said, adding that the results will be more solid if it can be backed up by what other teams found. “We actually need more than one group going after this old ice. Because we’re probably not going to completely believe it unless we replicate it.”

The U.S. has an outsized presence in the scientific community in Antarctica, Neff said. “We just can do so much, and most other countries are watching what we do and learning from what we do and following our lead on the science,” he said. 

While polar research, like space exploration, has historically been a realm of wide collaboration where political division melts away, Russia’s invasion of Ukraine upended that balance, Neff said.

“Of course, now nobody collaborates with the Russians,” Neff said, adding he’s now partnering with Korean researchers on a project after they withdrew from a separate project they had planned with Russia before Russian troops attacked Ukraine a year ago.

Facing climate change and biodiversity loss, humanity is in a fragile time. Scientists call it the sixth mass extinction.

Nunn uses the term “rapid climate change.” Compared with the time scales of ice cores, the recent centuries when humans have warmed the planet – the window from the Industrial Revolution until today – are a collective blip. 

That carbon dioxide concentrations have increased so sharply in a matter of decades is what alarms folks like Nunn.

“Right now, we are in an incredibly bizarre time,” he said. “When we look at these changes that happen naturally, they take place over thousands of years. We’ve condensed that into a few decades.”

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