Usually devoid of human presence, the Müller Ice Cap is currently home to a 10-person team of Canadian and Danish scientists on an ambitious quest to drill through the ice to the bedrock below.Alison Criscitiello/Supplied
Those who venture onto the Müller Ice Cap experience something akin to walking on a giant snow-covered roof.
Vast, high and more than 600 metres thick, the ice cap sits astride Axel Heiberg Island in Canada’s Arctic Archipelago.
Usually devoid of human presence, it is currently home to a 10-person team of Canadian and Danish scientists on an ambitious quest to drill through the ice to the bedrock below.
Their goal is to extract 10 to 20 thousand years’ worth of climate history, reaching back to a time when vast sheets of ice covered most of the country.
Located about 100 kilometres west of the Arctic Ocean, the sprawling Muller Ice Cap on Axel Heiberg Island is ideally placed to record the climate history of the western High Arctic.Alison Criscitiello/Supplied
“We have been thinking about this ice core for more than 10 years,” said Dorthe Dahl-Jensen, the expedition’s leader. “There are only a few spots left in Canada where the ice hasn’t disappeared – we think Müller is one of them.”
Born and educated in Denmark, Dr. Dahl-Jensen has studied ice cores her entire research career, much of it at the University of Copenhagen’s Centre for Ice and Climate. Since 2019, she has also been a professor at the University of Manitoba, where she holds a $10-million Canada Excellence Research Chair, a major funding source for the expedition to retrieve an ice core from the Müller Ice Cap.
“This is an unprecedented opportunity,” said Alison Criscitiello, a co-leader on the project and director of the Canadian Ice Core Laboratory at the University of Alberta. “It will be the deepest core ever drilled in Arctic Canada.”
Altitude and geography have combined to make the Müller ice cap such a valuable repository. It receives a steady accumulation of snow each year, with each annual load compressing the layers below into a tight, frozen stack.
Core principles
A Danish-Candian team aims to extract a 600-metre long core from
the Muller Ice Cap to access the region’s long-term climate history.
Detail
Drilling site
Muller Ice Cap
Arctic Ocean
Axel Heiberg Island
CANADA
50 km
the globe and mail, Source: openstreetmap
Core principles
A Danish-Candian team aims to extract a 600-metre long core from
the Muller Ice Cap to access the region’s long-term climate history.
Detail
Drilling site
Muller Ice Cap
Arctic Ocean
Axel Heiberg Island
CANADA
50 km
the globe and mail, Source: openstreetmap
Core principles
A Danish-Candian team aims to extract a 600-metre long core from
the Muller Ice Cap to access the region’s long-term climate history.
Detail
Drilling site
Muller Ice Cap
Arctic Ocean
Axel Heiberg Island
CANADA
50 km
the globe and mail, Source: openstreetmap
Encased within are traces of anything that was deposited by winds blowing in from the Arctic Ocean about 100 kilometres to the west – providing information about long-term climate trends. For example, bromine and iodine from ocean salts can reveal how much open water there was at different times in the past. And this deep, prehistoric record can be calibrated to modern measurements, revealing the region’s past response to global change as well as a glimpse of what lies in the future.
But while the ice has accumulated for centuries, the task of retrieving it must be done on a tight timeline to capture the entire ice core while the location is accessible.
Expedition leader Dorthe Dahl-Jensen inspects a section of the ice core. Born and educated in Denmark, Dr. Dahl-Jensen has studied ice cores her entire research career.Alison Criscitiello/Supplied
“We have to be done by the first week of June,” Dr. Criscitiello said. “There’s just enough surface melt that the planes will not land, so we can’t push it on the far end.”
With that deadline in mind, the expedition has started earlier than is typical for fieldwork in the high Arctic.
In late March, people and gear began arriving at the project‘s staging point at Eureka, Nunavut. From there, Dr. Dahl-Jensen and two colleagues were transported to the site by a Twin Otter plane on April 3.
Working at temperatures near -30 degrees, they began setting up camp. A critical task was using a snowmobile-towed groomer to prepare a runway for a much larger Basler aircraft to fly in some seven tonnes of cargo, including large tents and supplies needed for a two-month stint atop the windswept ice cap. By April 7, the entire team was in place.
The team‘s drilling site was pinpointed two years earlier using a combination of remote sensing data and measurements taken from the surface with ice-penetrating radar.
At the time, a key consideration was finding a site that is relatively static at depth. While the ice cap appears immobile to the human eye, it is a dynamic presence on the landscape with channels of slow moving ice that flow outward from its centre.
The Müller ice cap receives a steady accumulation of snow each year, with each annual load compressing the layers below into a tight, frozen stack.Alison Criscitiello/Supplied
Another concern was making sure the ice under the drilling location is as deep as possible.
“The rock underneath is pretty mountainous, so you get quite a bit of variation in the ice thickness,” said David Lilien, a glaciologist at Indiana University who was part of the site-selection expedition team in 2023. “If you were off by even half a kilometre on the surface, your ice thickness could change by 50 per cent.”
For the current crew, the sun stopped setting at the drilling site by mid-month and temperatures were hovering around “a very pleasant” -20 degrees, according to Dr. Dahl-Jensen.
“We do not want temperatures too high for the ice cores,” she said.
Alison Criscitiello, director of the Canadian Ice Core Laboratory at the University of Alberta is working on a series of shorter (100-metre) ice cores that can reveal history of airborne contaminants deposited on the ice in recent history.Alison Criscitiello cu/Supplied
Now working in continuous daylight, the team erected a temporary freezer that will server as the first link in a cold chain for transporting sections of ice core to their final destination at Dr. Criscitiello’s Edmonton laboratory.
During Easter weekend, the insulated building doubled as a shower – a rare treat – before it was returned to freezing temperatures so that the first ice cores could be stored inside.
The drill consists of a metal tube that bores into the glacial ice and removes the cores one length at a time. When the drilling commenced a week ago the operation soon passed through the top layer of accumulated snow and into the denser ice below.
By April 21, the team was working in shifts from 8 a.m. to midnight, reaching a depth of 96 metres. Toward the bottom of that depth, a change in the ice revealed the presence of residue from the massive eruption of Laki, an Icelandic volcano, in 1783.
“We have drilled through 242 years of ice,” Dr. Dahl-Jensen wrote in the log that day.
Now the extraction has become more challenging because of the pressure difference between the ice at depth and the surface – a change that can cause ice cores to fracture. To counteract this, the team has begun adding a non-hazardous drilling fluid to the lengthening borehole.
Members of the Muller Ice Cap drilling team posed for a group picture after an Easter egg hunt earlier this month.Emma Ausin/Supplied
By April 24, the team had reached a depth of 140 metres.
Meanwhile, Dr. Criscitiello has been leading a parallel effort to drill out a series of shorter ice cores of about 100 metres in length to obtain more information about the more recent history of the Arctic. These cores will be used to probe for lead, arsenic, polyfluoroalkyl substances (PFAS), microplastics and other chemical contaminants that ride like hitchhikers on tiny particles of dust and are transported to the Arctic by global winds.
“It requires a lot of sample volume to measure these,” Dr. Criscitiello said, so the more shallow cores they can drill alongside the main, deep ice core, the better. It could be many years before the convergence of expertise, equipment and resources makes another such opportunity possible.
“It is very exciting to finally see the ice-cap drilling campaign under way this year,” said Laura Thomson, a Queen’s University glaciologist who is not part of the project but is conducting long-term monitoring of glacial ice about 50 kilometres south at Expedition Fjord.
Dr. Thomson said her own work shows that Canada’s ice caps are changing because of rising temperatures during the summer months. For now, the excess melt water often percolates downward and refreezes. But in time, it is expected to contribute to sea-level rise.
“We should remember that Canada hosts the largest area of glaciers on Earth, outside of the Greenland and Antarctic ice sheets,” Dr. Thomson said. “It is important we understand their history so we can anticipate and prepare for their future.”
Editor’s note: A previous version of this story incorrectly spelled Laura Thomson’s surname. This version has been corrected.