In a Penn State lab, a small cylinder of soil sits wired with sensors, slowly cooling as it mimics conditions thousands of miles away.
At first, it looks unremarkable, like dirt from an average backyard mixed with water. But as the temperature drops, the sample begins to freeze, and its internal structure shifts in ways that are invisible to the eye. Each measurement adds another piece to a complex puzzle, one that connects microscopic structures in a lab to vast landscapes in the Arctic and to global systems that affect people everywhere.
To a group of faculty and student researchers at Penn State, those changes carry critical information about one of the most pressing environmental challenges on Earth: the thawing of Arctic permafrost.
"When you think of the Arctic, maybe you picture a frozen iceberg or the mesmerizing Northern Light or the lonely arctic fox," said MD Mashfiqur Rahman, doctoral candidate in engineering science and mechanics. "But you definitely won't imagine a piece of scrubby brown dirt. But that brown dirt is permafrost."
Permafrost is soil that remains frozen for at least two consecutive years. It is found across vast regions of the Arctic, including Alaska, northern Canada and Siberia. Permafrost is typically found immediately below the "active layer" - the surface layer that thaws each summer and refreezes in winter - so it can start within tens of centimeters to a few meters of the ground surface depending on local conditions. In terms of total thickness, permafrost varies widely: In warmer/discontinuous zones, it can be only a few to a few tens of meters thick, while in cold continuous permafrost regions it's commonly hundreds of meters thick and in some places can exceed 1,500 meters, or nearly 5,000 feet.
While temperatures are rising globally, those regions are warming especially fast.
"The problem is these regions are now warming four times faster than the rest of the world," Rahman said. "That's enough to start the permafrost thaw, and it's definitely something we should be concerned about."
Understanding that relationship is the focus of the Penn State team's research, work that is part of a multi-university collaborative project led by Saint Louis University. Each partner plays a distinct role. Researchers at the Ohio State University focus on interpreting satellite signals, analyzing how those signals reflect off the ground. The University of Alaska contributes field expertise and access to permafrost regions, helping connect laboratory findings with real-world conditions.
Researchers at Saint Louis University fly drones over permafrost in Alaska to collect electromagnetic data and provide the team with mechanical and thermal property data.
Penn State's contributions to the project - which the researchers called both technical and deeply human - pull from across several Penn State institutes. The Materials Research Institute, the Huck Institutes of the Life Sciences, the Institute of Energy and the Environment, and the Institute for Computational and Data Sciences all contribute tools, expertise or analysis.
"It's not only the equipment, the facilities, but it's also the people in the facilities that are amazing," said Mike Lanagan, professor of engineering science and mechanics at Penn State, who leads Penn State's role in the project. "It's very knowledgeable people within these facilities that really help us out. It's a big effort, and a collaborative one. Being able to work this closely with the other universities has been both great for Penn State and great for the project."
