Alison Criscitiello, National Geographic Explorer, ice core scientist and high-altitude mountaineer, details her most recent expedition Thursday in the Amphitheater.
Alison Criscitiello has studied ice cores from some of the most remote regions of the world, including Canada’s Mount Logan, the second-highest peak in North America and located in the largest non-polar ice field in the world.
Mount Logan stands on lands sacred to the Kluane, Champagne-Aishihik and White River First Nations, and Criscitiello thanked her team’s First Nations partners for allowing Criscitiello’s ice core expeditions. She also credited her Ph.D. student Kira Holland as a key member of her team conducting analysis of the ice core.
“I am a single person presenting work that took an enormous team to pull off,” Criscitiello said during her lecture Thursday morning in the Amphitheater, speaking as part of the Chautauqua Lecture Series Week Eight theme, presented in partnership with National Geographic: “Water: Crisis, Beauty and Necessity.”
Measuring climate change on Canada’s highest peak poses a unique set of challenges, and Criscitiello’s experience as a high-altitude mountaineer is as vital as her scientific expertise. Mount Logan regularly experiences heavy snowfall and hurricane-force wind gusts. Outside the polar regions, few places on Earth sustain cold-enough temperatures to preserve long-term climate records in ice. Due to the cold mean annual temperatures, ice at locations like Mount Logan has remained frozen for tens of thousands of years, scientists estimate.
Mount Logan’s unique assets make it essential for climate researchers, but also make summiting it a dangerous task.
“We’ve long known that Logan, with its enormous, cold, high-summit plateau may possibly contain the longest record of North Pacific climate variability on earth,” Criscitiello said.
Criscitiello described the 2021 and 2022 expeditions to drill the Mount Logan ice core. In 2021, she summited Mount Logan to place a weather station and conduct a radar survey of the mountain’s summit plateau. Radar surveys were necessary to narrow down the location from where the ice core would be taken. Additionally, meteorological data collected by the weather station will help scientists determine how high altitudes are impacted by the warming climate. Criscitiello emphasized that data measuring these rapidly warming regions is lacking.
In 2022, Criscitiello again submitted Mount Logan with a team of seven. The team conducted a final radar survey to pinpoint the ideal drilling spot for the ice core. Criscitiello technically climbed the mountain twice in this single expedition, as the method the team followed required them to transport gear to a camp up the mountain and return to sleep at a lower altitude, repeating this process at each ascending camp. This technique, she said, is gentler on the body, as it allows mountaineers to acclimatize and eventually remain at the higher altitude of the summit for a longer time with a lower risk of altitude sickness.
However, “lower” is relative, and Mount Logan — like any of the Earth’s great peaks — is brutal on the body. During the 2022 expedition, three members of Criscitiello’s team required emergency medical evacuation. Criscitiello, well aware of Mount Logan’s unforgiving nature, had prepared for this eventuality.
Once the team reached the drilling location on the summit plateau, more pressure was put on the remaining scientists. In order to have the drill running as long as possible, Criscitiello split the expedition into two teams of two who ran the drill in shifts, manning the drill for 14 hours a day and rotating every two or three hours depending on weather.
The location Criscitiello’s team eventually decided to drill had ice approximately 1,000 feet deep.
The drilling equipment was transported to the mountain in multiple small loads (each about 300 pounds) by helicopter. Only one helicopter in the Yukon region, where Mount Logan is located, is modified to fly at altitudes that high. Ordinarily, the helicopter only operates for high-altitude rescue missions; however, an exception was made for Criscitiello’s expedition.
The helicopter returned periodically throughout the team’s stay at the summit, transporting pieces of the ice core as it was packaged. Transporting the ice periodically, rather than waiting for the entire core to be collected, allowed the team to pack up and ski to base camp soon after the final pieces of the core were removed. Criscitiello wanted her team to return to lower altitude as soon as possible.
The team drilled for nearly two weeks before the final ice core samples were transported off the mountain. In total, the expedition lasted a little more than three weeks: nine days to summit Mount Logan, two weeks of drilling, and seven hours to descend back to the base.
Why did Criscitiello and her team brave such brutal conditions for a (admittedly large) sample of ice?
“The chemistry of ice cores offers a seemingly endless number of tools to investigate past climate,” she said.
Those tools can help scientists determine how humans are impacting the climate. While ice core scientists have collected and analyzed samples from other remote locations, including Antarctica and Greenland, Criscitiello and her team’s goal is to extract records of long-term North Pacific climate variability from the Mount Logan sample.
While Criscitiello was summiting Mount Logan, her student Kira Holland was leading an expedition to study how snow chemistry changes with elevation along the route to the mountain’s base camp. The data Holland’s team collected will provide context for interpreting data from the ice core.
After Criscitiello returned to her lab, the ice core was subjected to a wide variety of tests. First, they imaged the ice. Next, they established and executed a cut plan for the core. Over half of the ice core was archived for study by future scientists. The scientists also measured the electrical conductivity of the ice, and this process helped pinpoint where particles from volcanic eruptions lie in the core.
“We always use as little ice as possible,” said Criscitiello. Scientists hope that future techniques will be able to glean more data from the stored ice.
Criscitiello traveled to the Reno, Nevada, Ice Core Lab to conduct elemental analysis on the inner part of the core. The inner core is significant because this ice is completely pristine and unaffected by outside air. As the ice melts, continuous flow analysis is conducted. Sensors collect real-time continuous data from the melt water.
The process took approximately a month, and provided nearly all the chemical analysis that can currently be obtained from the ice core. Eventually, tests will be run to analyze the atmospheric gasses and wildfire indicating chemicals contained in the core.
After initial tests were run, Criscitiello’s team began dating the ice, a process that can take years, and different parts of the core require different techniques. In the upper core — the newer ice — dating can be established through seasonal markers and preserved chemical markers; season differences can cause visible differences in the ice. The deeper parts, the older ice, require more complicated analysis. Time is more compressed the deeper into the core one looks.
Scientists primarily rely on ice flow modeling and tie points to date older ice — tie points are events in Earth’s history that have created identifiable markers throughout all samples. For example, Criscitiello referenced nuclear bomb fallout from 1962 and 1963. The measurements of Uranium 238 can be used for dating, since the element caused a notable impact. Criscitiello also discussed how chemicals from volcano eruptions can date the ice, as well. Specialists in the field can determine the exact volcano and eruption that produced fallout found in ice cores, and that information can also be used for dating.
So far, Criscitiello’s team has dated annual layers through approximately 256 meters of the Mount Logan ice core.
Criscitiello’s expedition further established the fact that even the seemingly remote and untouched reaches of the world are impacted by human development and climate change. She explained that the phenomenon of elevation-dependent warming means scientists expect these high elevations to be some of the fastest warming in the future.
However, Criscitiello emphasized that it is not too late to implement change and “push the policy needle toward environmental sustainability and preservation.”
She pointed to the Intergovernmental Panel on Climate Change’s recent report as a place to look for those interested in further details about the state of the earth’s climate. Criscitiello also urged that while she sees hope for the climate, “the timeline to act is now.”
