91�鶹��Ʒ

Antarctica is like no other place on Earth. The continent has been locked in glaciers for 34 million years, with a mere 1% of the land surface free of ice sheets.

“It’s Earth’s radiator, central to how the planet maintains livable temperatures,” said Associate Professor of Earth and Environmental Geosciences Joe Levy. “The long-held perception is that Antarctica, unlike the Arctic, is very stable and its permafrost isn’t threatened.”

���𱹲�’s , however, reveals that Antarctica is changing in ways that will alter its influence on global climate and ocean patterns.  

The study started as a senior class project in 2023. Levy asked students to read a paper about the effects of warming Arctic winters on permafrost and then look for evidence of similar trends in Antarctica. “Existing Antarctic research all focused on summertime warming,” said Levy. “No one thought we needed to look during the winter. The average temperature is -30 Celsius, after all.”

The class analyzed publicly available wintertime data from 10 automated meteorological stations maintained through the , part of the National Science Foundation’s LTER Program. “You don’t have to go to Antarctica to be an Antarctic scientist, thanks to the amazing data they collect and publish,” Levy said. “My students loved digging into these nearly real-time data sets and being part of the discovery process.”

The students did indeed find consistent evidence of rising winter temperatures in the McMurdo Dry Valleys. At 1,900 square miles, the dry valleys comprise Antarctica’s largest ice-free region. “They’re our laboratory for understanding Antarctica’s land-based processes, including how water and dissolved nutrients run off the soil into the Southern Ocean,” Levy said. “They’re also a model for how Antarctica could function in a future with drastically less ice.”

The class’ findings inspired Levy and Gavin Fowler ’24, now a graduate student at the University of Chicago, to dig deeper. Fowler, who coauthored the new study, created the code to organize and analyze a massive amount of meteorological information: 30 years of soil temperature, air temperature, wind speed, and infrared radiation data collected by the 10 LTER stations.

“We were blown away to find that not only were winters getting warmer — the rate of warming is greater in winter than summer,” Levy said.

When the permafrost can’t freeze as deeply in winter, more melting and erosion can occur in summer whether summertime temperatures are increasing or not. “Think of scooping ice cream that’s frozen through. Then think about ice cream that hasn’t been in the freezer long,” Levy said. “It’s softer and a lot easier to scoop. You reach lower levels and expose them more quickly. Then they melt more quickly.”

Hurricane-like winter windstorms are known to push warmer air across the dry valleys. When Levy and Fowler removed wind from the data, however, they still saw “background warming.” “This demonstrates the air is getting warmer in winter independent of local weather in a particular valley,” Levy said.

“For geoscientists, this is a wake-up call. We need to think differently and put aside preconceptions about Antarctica’s stability,” Levy said. “Students were instrumental in this project because they didn’t bring those preconceived notions.”

Over time, Antarctica may evolve from a cold desert reminiscent of the Martian landscape to an ecosystem akin to Arctic tundra. Levy projects that the first permafrost could completely thaw and vanish from Antarctica as early as 2130. “In geological terms, 2130 is remarkably close,” he said.

How this evolution will influence Earth’s climate, oceans, and life in temperate zones over the coming decades will be an important topic for further research. ���𱹲�’s own near-term next steps include using satellite remote sensing and a network of ground sensors to learn how widespread wintertime warming is across the continent and confirm the rate of warming in locations outside the dry valleys.

“This project confirms in my mind that the change is inevitable. That means the coming loss of a very special place,” Levy said. “But if we hadn’t realized what’s happening to the permafrost now, we would’ve been blindsided by the time the effects are significant.”

“Antarctic scientists do what we do to prepare people everywhere for what the future holds,” Levy said. “The more we know about how Antarctica is changing, the more we can prepare. Now we have a date, and we can plan for what comes after the thaw. That makes me hopeful.” 

— Meghan McDonald