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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��,” 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��. 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,��.

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��. 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:

Thawing the Mysteries of ancient climate changes (INSTAAR)