An international team of researchers has found widespread and accelerating permafrost degradation across the Arctic, Antarctic and high-mountain regions, drawing on more than two decades of field observations from 156 monitoring sites around the world.
The study, published in Nature Communications Earth & Environment, shows that the active layer—the uppermost layer of ground that naturally thaws each summer and refreezes in winter—is getting deeper at monitoring sites across the globe. The findings provide clear evidence that permafrost degradation accelerated between 2000 and 2024, signaling major changes in some of the planet’s most climate-sensitive landscapes.
University of Victoria (UVic) economist Felix Pretis provided the statistical analysis linking observed thaw to temperature and precipitation.
Climate changes versus local weather
Pretis explains how monitoring sites can vary widely in soil, vegetation, terrain and ice content—all factors that influence how deeply the ground thaws. That makes direct comparisons between sites difficult because differences may reflect local conditions rather than climate change.
UVic’s analysis compared each site with its own history, tracking yearly changes. The researchers used statistical methods commonly used in economics, known as panel methods, to separate long-term, climate-driven changes from local conditions that affect individual sites.
If you simply compare one site to another, you badly overstate how sensitive permafrost is to climate, so we tracked each site against its own record instead. In the Arctic lowlands that gives a clear picture: hotter summers thaw the ground deeper, more rain adds a little on top of that, and cold winters do not hold the thaw back.”
—Felix Pretis, UVic economist
Permafrost vital to key infrastructure
Permafrost is ground bound together by ice that remains frozen for at least two consecutive years. It underlies nearly 15 per cent of land surface in the northern hemisphere and nearly all ice-free land in Antarctica. A thickening active layer indicates that ice deeper in the ground is thawing, which threatens roads, pipelines, buildings and utility systems, and releases carbon stored in permafrost soils as carbon dioxide and methane.
The significance of this study lies in the fact that we’re not just looking at isolated hotspots anymore. The collaborative efforts of the involved sites show a pattern that spans continents and climate zones, telling us that global permafrost degradation is already well underway.”
—Dmitry Streletskiy, lead author and professor of geography and international affairs at George Washington University
The key findings show the permafrost is thawing across the Arctic, Antarctic and mountain regions at a quicker rate than previously recorded with mountains changing the fastest. The layer of ground that thaws each summer is getting deeper at 55 per cent of Arctic sites, 38 per cent of Antarctic sites and more than 90 per cent of monitored mountain sites. The study is the first global assessment of long-term active layer monitoring data and the product of field teams in more than 20 countries.
