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What can a mile-long stick of ice, stored away for 33 years, tell us about Earth’s climate?

Gabe Allen — Thu, 11 Dec 2025 17:43:41 +0000

What can a mile-long stick of ice, stored away for 33 years, tell us about Earth’s climate? Gabe Allen Thu, 12/11/2025 - 10:43

After years as a professional research assistant at INSTAAR’s stable isotope lab, Valerie Morris estimates she’s processed more than 10 kilometers of ice from around the world.

“You’ve done more ice than the Bolder Boulder,” co-principal investigator Tyler Jones joked around a table at the lab recently. “She’s done more high-resolution ice measurements than just about anyone in the world.”

Valerie Morris loads an ice core sample into a carousel in the stable isotope lab at INSTAAR. The carousel is the front end of a continuous flow analysis system developed by Morris and Bruce Vaughn, which continuously measures isotopic ratios for hydrogen and oxygen as the ice core melts. (Gabe Allen)

This fall, Morris loaded yet another chunk of ice into the one-of-a-kind ice analysis system at the lab. But, this one was significant. It was the final sample for a project that she and other lab members began a year-and-a-half before — to reanalyze an ice core that was drilled 33 years ago in Greenland using modern techniques.

The ice core in question was extracted at the Greenland Ice Sheet Project Two (GISP2) from 1988 to 1993. It took scientists five years to drill down from the top of the ice sheet to the bedrock. They were left with a cylinder of ice more than a mile long.

Though the effort was great, the payoff was worth it. Within the ice were chemical signatures of past temperatures, climate shifts and volcanic eruptions. The deeper those signatures, the older. At its base, the ice core dated back more than 100,000 years.

Brooke Chase looks at a readout of isotopic ratios from an ice core as Bradley Markle (left) and Tyler Jones (right) look on. (Gabe Allen)

Shortly after the ice core was extracted, researchers analyzed the chemical contents of samples spanning its length. Their results, combined with other records, provided a better understanding of Earth’s climate history from the start of the last ice age to today.

Yet, this earlier analysis was also limited. Sampling methods at the time required the scientists to melt down meter-long chunks of ice at a time. That meant, at best, each data point represented an average over about a decade of history.

Today, technicians at the stable isotope lab use a system developed by Morris and INSTAAR fellow emeritus Bruce Vaughn in 2009. Instead of measuring large, discrete chunks of ice, the system melts each sample slowly from tip to tail. As the sample melts, the water is quickly sucked into a matrix of instruments. The technique allows the scientists to analyze the ice millimeter by millimeter — literally.

The team of scientists that reconstructed the length of the GISP2 ice core poses at the NSF-Ice Core Facility. From Left to Right: Rhys-Jasper Leon, Richard Nunn, Ella Johnson, Valerie Morris, Adira Lunken, Brooke Chase, Tirso Jesus Lara Rivas, Max Eshbaugh, Megan Erskine, Theo Carr.

Using this method, lab members knew they could unlock new information in what was left of the GISP2 ice core, which has been stored in the National Ice Core Facility in Lakewood for the past three decades. Though much of the volume of the ice core was consumed by previous analyses, almost all of its length was preserved in the archive. Over the past year-and-a-half, Morris, PhD student Brooke Chase, and a team of research assistants reconstructed more than a mile of ice from GISP2 and ran it through the instruments at the lab.

The data they gathered has the potential to answer pressing questions about Earth’s past climate. Last winter, the lab published a new paper identifying periods of climatic stability preceding abrupt warming events during the last ice age. That analysis relied on data from the newer East Greenland Ice-Core Project. Chase is now busy processing and analyzing the data from GISP2, and the preliminary results seem to contradict these earlier findings.

“Brooke has some preliminary results suggesting that we are not getting the same answers,” Jones said. “But we only have a small chunk of time so far, so we’re sitting here waiting until we have the final data.”

Resolving these contradictions might unlock a new understanding of these abrupt warming events in the past, or it might further muddy waters. Either way, the researchers now have much more detail to parse through than before. The new project provided around 1,000 times more data points per meter of ice than the previous sampling effort. At its best, each value now represents a few months of climate history.

“What were trying to do with this project is see what Earth was capable of at higher frequencies,” Jones said. “You lose the ability to look at variability in the climate when you only measure every meter. But if you can look at a higher resolution, you can see those changes.”

Although ancient history may seem far removed from the pressing concerns of modern climate change, it's more relevant than it appears. Understanding how Earth’s climate evolved is essential to scientist’s ability to understand current climate dynamics and predict future outcomes.

“We only have about 40 years of satellite observations of Earth’s climate, and a few hundred years of people standing around with thermometers,” co-principle investigator Bradley Markle explained. “The time scales that people care about are on the order of decades and centuries, but to understand variability on those time scales you have to look at records of Earth’s climate over thousands of years.”

Learn more:

What do ice cores reveal about the past? (National Snow and Ice Data Center)

Thawing the Mysteries of ancient climate changes (INSTAAR)

Inside an ice stream (Science)

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

Researchers at the stable isotope lab just finished resampling more than a mile of ice from Greenland. Further analysis will probe unanswered questions about climate change, sea ice and Earth’s history.

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Brooke Chase stands in the main storage area of the National Science Foundation Ice Core Facility. This part of the facility is held at -36 degrees Celsius and houses over 30,000 meters of ice from polar regions around the world.

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Local middle schoolers get a crash course in Earth science at INSTAAR

Gabe Allen — Fri, 25 Apr 2025 19:00:00 +0000

Local middle schoolers get a crash course in Earth science at INSTAAR Gabe Allen Fri, 04/25/2025 - 13:00

Gabe Allen

Earlier this month, Organic Geochemistry Laboratory manager Lennart van Maldegem posed a question to a group of eighth graders from behind a table jumbled with jars of candy, food coloring and pipettes.

“This is the organic chemistry lab, where we search for molecular fossils, they’re not visible,” van Maldegem said. “They’re mixed up in a rock with all of this other stuff, so how do we separate the fossils out? What do you think?”

“Explosions?” someone suggested, to laughter. In the end, the answer was, of course, chemistry. For the next 15 minutes, the students took turns pipetting food coloring onto coffee filters, adding water and then watching as the die separated into its composite colors.

“Candy chromatography” was just one of 12 activities that INSTAAR researchers organized during the annual INSTAAR Middle School Showcase. Throughout the day, more than 200 students from Angevine Middle School traversed the Sustainability, Energy and Environment Community campus in small groups.

INSTAAR PhD student Robert Kelleher shows students how to conduct a "candy chromatography" experiment. Gabe Allen, 2025.

Drones and daylight

INSTAAR PhD student Kevin Rozmiarek shows Angevine Middle School eighth graders how to operate a research drone on at the INSTAAR Middle School Showcase. Gabe Allen, 2025.

In one activity on the southwest lawn, PhD student Kevin Rozmiarek showed students how to operate a research-grade drone equipped with a thermal camera. Rozmiarek has led research efforts to measure atmospheric gasses in Alaska and Greenland using similar aircraft. He explained that the same drones used for research also support the University of Colorado’s Police Department and Emergency Management team during events.

Scott Kittelman at the Skywatch Observatory outside the Sustainability, Energy and Environment Community building during the INSTAAR Middle School Showcase. Gabe Allen, 2025.

On the other side of INSTAAR’s campus, University of Colorado Department of Atmospheric and Oceanic Sciences professional research assistant Scott Kittelman gave students a tour of the University of Colorado “Skywatch Observatory.” Using various analogies and examples, Kittelman explained how the instruments at the observatory measure a wide variety of atmospheric conditions.

Kittelman focused especially on the pyranometer, which measures solar radiation. He told the students that the simplest possible experiment would be to measure when it got light, at sunrise, and when it got dark, at sunset everyday.

“What would I learn, scientifically? Kittelman asked his audience. “I might learn something about the seasons on this planet—that the day length changes. And, if I learned that the days were longer, and I was measuring temperature too, I might find that there is a relationship between temperature and the day length.”

The next generation

Kittelman has been an avid science educator throughout his career. He says his motivation is simple. Good science education lays the foundation for a new generation of scientists.

“Science is about inspiration. If you inspire kids early on, they find they have a talent for it and you get the best scientists that way,” Kittelman said. “Einstein’s father inspired him when he gave him a toy compass and explained that the needle was compelled by magnetic forces.”

INSTAAR chatted with a dozen or so students over lunch, in between the workshops and the bus ride home. Everyone seemed to come away from the day with a slightly different takeaway. Some reflected on a new insight.

“You have to learn about the past before you can say anything about the future,” Edward said, citing his group’s trip to the Stable Isotope Lab’s ice core freezer. “You see how it was back then to see how it is today.”

Others were enamoured with the scientific instruments they encountered.

“It was pretty cool when the guy flying the drone could see all the way across Boulder,” Kyoshi said.

Almost everyone agreed on one thing. Touring INSTAAR was better than being back at school. And, if skipping school for a day is the thing that inspires the next Nobel laureate, so be it.

Click an image below to enlarge.

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

More than 200 students from Angevine Middle School recently visited INSTAAR, where researchers led hands-on demonstrations. The goal of the showcase is to inspire future scientists at an impressionable age.

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Drone experiment reveals how Greenland ice sheet is changing (CU Boulder Today)

Gabe Allen — Thu, 27 Mar 2025 20:38:25 +0000

Drone experiment reveals how Greenland ice sheet is changing (CU Boulder Today) Gabe Allen Thu, 03/27/2025 - 14:38

An INSTAAR-led study measured water vapor in Greenland’s air, collecting data crucial for improving climate models and forecasting Arctic changes.

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Thawing the mysteries of ancient climate changes

Gabe Allen — Wed, 26 Mar 2025 19:00:00 +0000

Thawing the mysteries of ancient climate changes Gabe Allen Wed, 03/26/2025 - 13:00

Gabe Allen

A new study from Chloe Brashear, Tyler Jones and others suggests abrupt warming events were preceded by periods of unusually stable temperatures during the last ice age. The researchers point toward shifting sea ice as a potential driver of the phenomenon.

On July 21, 2019, Chloe Brashear carried another disc of ice through the underground ice cave at the East Greenland Ice-Core project. The cave lay a few meters below the surface of the sprawling Greenland ice sheet, more than 200 miles inland from the coast. Brashear loaded the disc onto a hot aluminum plate and then stepped into the sampling room, where the melt water was pumped through an array of equipment that would filter it, vaporize it and produce a readout of its chemical contents.

Despite the sub-freezing temperatures in the cave, space heaters and an array of whirring instruments kept the sampling room hot. Brashear cast off her parka and got to work.

In most ways, it was a typical day of late-summer field work, but this day was also special. Brashear and her colleagues were analyzing samples extracted from deep within the ice sheet—more than 2,000 meters below the surface. The scientists estimated that the ice was more than 40,000 years old. Later that night, they would celebrate over drinks and grub.

Chloe Brashear poses in the drill trench at the East Greenland Ice-Core Project. Photo courtesy of Chloe Brashear.

New Insights

Five years later, Brashear—now a PhD candidate at Utrecht University in the Netherlands—has teamed up with her former mentor, INSTAAR fellow Tyler Jones, and others to publish new insights from their 2019 expedition. Their new study takes a fresh look at some of the most dramatic climate upheavals in Earth’s history: abrupt warming events that punctuated the last ice age, between 11,000 and 50,000 years ago.

The data revealed something unexpected. On average, the colder periods between warming events displayed variable temperatures—it might be very cold one decade and much warmer the next. But, during the few hundred years before an abrupt warming event, this volatility flattened out. Each rapid warm-up was preceded by centuries of unusually stable temperatures.

“Variability would start to decrease first at decadal and multi-year scales,” Jones said. “Then, a few hundred years later, on average, there would be an abrupt warming event.”

It was as if the climate system was holding its breath before suddenly exhaling in a burst of warmth. But why?

The new paper proposes that shifting sea ice conditions in the North Atlantic may be the missing puzzle piece. If their hypothesis is correct, it could reshape our understanding of Earth's climate system—especially in times of abrupt change.

Ice age heat

If the phrase "abrupt warming event" makes you think of modern climate change, you're not wrong. But, the events that Brashear and Jones focused on in their latest paper, known as Dansgaard–Oeschger events, were actually much more intense. Researchers estimate that, in the most extreme version of their projections, temperatures in Greenland may have risen by as much as 29 degrees Fahrenheit in less than a decade.

“As an analogy, imagine you live in Northern Maine when you start college, and by the time you finish college it feels like you’re living in Southern Arizona,” Jones said.

Climatic variability—basically the volatility of temperature fluctuations—has already been a focus of researchers hoping to understand the last glacial period. But, previous research lacked the precision needed to parse out the timing between changes in variability and these extreme warming events.

Freshly-drilled ice cores are stored in the ice cave, where they await processing and analysis. Photo courtesy of Tyler Jones.

That changed when Jones and his colleagues, including INSTAAR faculty Bruce Vaughn, Valerie Morris and James White, developed a new methodology for analyzing ice cores: continuous flow analysis. Instead of chopping an ice core into chunks and analyzing each separately, continuous flow analysis melts the core tip to tail, extracting a near-unbroken record of past temperatures. This allows scientists to study changes in climate on a millimeter-by-millimeter scale. In the case of this project, continuous flow analysis allowed Brashear to interpret temperature data for distinct intervals of 7 to 15 years of ancient history.

“If you continuously sample the ice core, you capture all this detail that you are losing with discrete sampling,” she said.

This technique provided the new paper’s biggest insight: the stable temperatures that preceded each of the Dansgaard–Oeschger events. It also provided Brashear with a powerful dataset to compare to sea ice models.

The comparison once again produced an intriguing result. The changes in temperature variability were highly correlated with modeled changes in sea ice variability. In the new paper, Brashear provides a hypothesis: the leading edge of North Atlantic sea ice may have become more stable, which would have decreased its influence on short-term temperature fluctuations in Greenland.

If true, the finding could influence scientists seeking to refine models of Earth’s climate and gain insights into the modern era.

“This result doesn’t directly apply to the modern changes we’re seeing, because they are unprecedented,” Jones said. “But, our hope is that we can shed light on the mechanisms that gave rise to this lead-lag relationship in variability and temperature, and then pass those results on to the modeling community.”

The next chapter

The researchers are cautious to not overstate their results. After all, the sea ice hypothesis is just one of several possible explanations. More evidence is needed.

Some of that evidence may come soon. Jones’ lab has secured funding to reanalyze an ice core extracted in the late 1980s and early 1990s from a site 200 miles south of the East Greenland Ice-Core Project. Using continuous flow analysis, they hope to confirm the patterns Brashear identified and gain further insight into these ancient climate shifts.

“We’re hoping we can replicate the result and push further into modeling,” he said.

The final chapter of Brashear’s research at INSTAAR is now over, but the experience of working in the remote scientific encampment atop the Greenland ice sheet remains vivid. She looks back with fondness on long days in the underground lab, neverending Arctic sun and nights spent celebrating new discoveries with international collaborators.

“It’s awesome to be able to look at a dataset and then have these memories associated with it,” she said. “It helps you stay motivated… I’m still pursuing a career in science, so you could say it had a positive impact.”

A line of national flags waves in the arctic wind. 15 Institutes from 14 different countries participate in research at the East Greenland Ice-Core project. Photo courtesy of Tyler Jones.

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

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Winterized tents house researchers atop the Greenland Ice Sheet at the East Greenland Ice-Core Project. The centerpiece of the camp, a black geodesic dome, and the red mechanic’s garage can be seen in the distance. Photo courtesy of Tyler Jones.

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Cover photo: Winterized tents house researchers atop the Greenland Ice Sheet at the East Greenland Ice-Core Project. A black geodesic dome and a red mechanic’s garage can be seen in the distance. Photo courtesy of Tyler Jones.

Inside an ice stream (Science)

David J Lubinski — Fri, 14 Feb 2025 03:58:01 +0000

Inside an ice stream (Science) David J Lubinski Thu, 02/13/2025 - 20:58

A hole drilled into Greenland's heart reveals ice ready to slide into the sea. An international group of researchers - including Tyler Jones - discuss their research and its often ominous implications. Don't miss the fantastic photos too!

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What was behind the seismic boom that wrapped Earth for 9 days? (Grist)

Anonymous — Mon, 30 Sep 2024 22:35:33 +0000

What was behind the seismic boom that wrapped Earth for 9 days? (Grist) Anonymous (not verified) Mon, 09/30/2024 - 16:35

A melting glacier collapsed, sending the mountaintop it propped up careening into the Dickson Fjord in East Greenland. The impact created a 650-foot tall tsunami, which crashed back and forth between the steep channel walls. Tyler Jones puts the event into the context of arctic climate change.

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New fossils reveal an ice-free Greenland. It’s bad news for sea level rise. (Grist)

Anonymous — Thu, 08 Aug 2024 16:57:33 +0000

New fossils reveal an ice-free Greenland. It’s bad news for sea level rise. (Grist) Anonymous (not verified) Thu, 08/08/2024 - 10:57

“We’re creating a world where these ice sheets are going to melt,” says Tyler Jones, explaining the results of a new study on fossilized plant and insect parts found at the bottom of Greenland's ice sheet.

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Meet the scientists behind the ice sanctuary — a memory vault for dying glaciers (Grist)

Anonymous — Fri, 02 Aug 2024 03:48:32 +0000

Meet the scientists behind the ice sanctuary — a memory vault for dying glaciers (Grist) Anonymous (not verified) Thu, 08/01/2024 - 21:48

Glacial ice contains valuable data about climates past. Researchers like Tyler Jones are working to preserve those records for the future. A number of science teams are archiving ice cores in a remote cave in Antarctica, where the average temperature is -54 degrees Celsuis (-65 degrees Fahrenheit).

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Old core, new data: Students unlock knowledge about past Arctic climates

Anonymous — Thu, 27 Jun 2024 16:55:34 +0000

Old core, new data: Students unlock knowledge about past Arctic climates Anonymous (not verified) Thu, 06/27/2024 - 10:55

Shelly Sommer

A team of students and scientists are reanalyzing the GISP2 ice core, drilled in Greenland during the late 1980s through the early 90s, to investigate mechanisms of abrupt climate change and extreme events of the past.

Assistant Research Professor Tyler Jones, Assistant Professor Brad Markle, and Senior Professional Research Assistant Valerie Morris of INSTAAR’s Stable Isotope Lab are leading a group of students in resampling the Greenland Ice Sheet Project Two (GISP2) core. Water isotopes in the core were originally analyzed to give insight into environmental change in the Arctic over the past 100,000 years.

Now Jones’ group is taking samples from the same core, stored for decades, and analyzing them afresh.

Analytical techniques developed over the past decades mean the team is getting much more detailed data about Earth’s past climate, unlocked from water isotopes.

Jones says, “The original measurements yielded about 3,000 data points over 3,000 meters of ice. Now we will get millions of data points over 2,000 meters of ice.” (The researchers are analyzing two-thirds of the core.)

Jones calls the team “an amazing group.” They include CU Boulder grad students Rhys-Jasper León and Brooke Chase, Front Range Community College student Megan Erskine, Colorado College undergrad student Tirso Lara, and CU Boulder undergrads Ella Johnson and Adira Lunken.

Click an image to zoom

Tyler Jones, Brad Markle, and Valerie Morris are leading a group of students in resampling the Greenland Ice Sheet Project Two (GISP2) core to investigate mechanisms of abrupt climate change and extreme events of the past. The original measurements (e.g., water isotopes) numbered a few thousand while the new measurements will create millions of data points.

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Photo: Tyler Jones, Rhys-Jasper León, Valerie Morris, Brooke Chase, Tirso Lara, Megan Erskine, Ella Johnson, and Adira Lunken work in the NSF Ice Core Facility, Lakewood Colorado.

Flight Ops supports INSTAAR research in Alaska (CU Boulder Public Safety)

Anonymous — Tue, 25 Jun 2024 23:43:51 +0000

Flight Ops supports INSTAAR research in Alaska (CU Boulder Public Safety) Anonymous (not verified) Tue, 06/25/2024 - 17:43

For the second summer in a row, the CU Boulder Division of Public Safety's Flight Operations department is supporting important campus research in Alaska, as part of the Navigating the New Arctic project (principal investigator: Tyler Jones), which is being managed by researchers in the Stable Isotope Lab of INSTAAR.

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Jones

What can a mile-long stick of ice, stored away for 33 years, tell us about Earth’s climate?

Related Articles

Local middle schoolers get a crash course in Earth science at INSTAAR

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Drone experiment reveals how Greenland ice sheet is changing (CU Boulder Today)

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New Insights

Ice age heat

The next chapter

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Inside an ice stream (Science)

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What was behind the seismic boom that wrapped Earth for 9 days? (Grist)

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New fossils reveal an ice-free Greenland. It’s bad news for sea level rise. (Grist)

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