Twenty-two percent of the Earth’s surface remains permanently frozen, a vast expanse exceeding 112 million square kilometers. This colossal layer, six and a half times the size of Russia and two hundred twenty-two times the area of Spain, is known as permafrost. As global temperatures rise, this frozen ground starts to thaw, threatening climate stability and the future of life on the planet.
Permafrost is a thick layer of soil, rock, or sediment that stays at or below 0°C year-round. It is most common in northern latitudes such as Greenland, parts of Canada, Alaska, and Russia, as well as at high elevations above the tree line and in regions that receive little snowfall.
The United Nations has long warned about the consequences of thawing permafrost and called for coordinated worldwide research. The rapid loss of land ice has drawn global attention, prompting scientists to study how permafrost thaw reshapes landscapes, displaces communities, and disturbs sensitive animal habitats. It also raises concerns about the release of long-trapped greenhouse gases like methane and carbon dioxide, accelerating climate change.
The latest assessment from the Federal Polytechnic School of Lausanne argues that permafrost in polar regions contains vast reserves of water, carbon dioxide and methane. These gases are potent drivers of climate warming. Michael Lehning, director of EPFL’s Cryospheric Sciences Laboratory, warns that releasing them could have catastrophic climate effects. That warning is echoed by researchers who stress the need to monitor thaw dynamics closely.
Microorganisms that may awaken
Thawing permafrost also releases microbes that have remained frozen for millennia. NASA has identified microbes in melted permafrost that are estimated to be more than 400,000 years old. While organic matter in permafrost is frozen and does not decompose under cold conditions, microbial activity after thaw can break down this material, releasing greenhouse gases into the atmosphere.
Scientists project that the Arctic will warm at two to three times the global average this century. When the global average is projected to rise by 1.5°C, the North could experience around 3°C of warming. This translates into more frequent extreme heat events and indirect effects such as forest fires and insect outbreaks, with broader ecological and social consequences.
In 2019, the United Nations Environment Program identified permafrost thawing as one of the ten most alarming emerging environmental challenges. Back then, the southern edge of Arctic permafrost had retreated northward by 30 to 80 kilometers, and this retreat has continued since. Polar regions are losing ground, and the implications extend far beyond the Arctic landscape.
Polar permafrost primarily consists of salt marshes and peat bogs with high moisture, where plant matter decomposes very slowly due to stubbornly low temperatures. This creates anaerobic conditions that store carbon for long periods.
“Sleeping giant” methane
Estimates place permafrost beneath the Arctic at twice the amount of carbon currently in the atmosphere, with a combined reservoir of carbon dioxide and methane far exceeding air levels. A 2015 study put the Northern Hemisphere’s total permafrost carbon at about 1,832 gigatons, underscoring the potential climate impact if thaw proceeds unchecked. The release of this reservoir could accelerate warming, although scientists still grapple with understanding the full range of feedbacks and compensation mechanisms.
Some researchers note that new plant growth may absorb some CO2, but the net effect remains uncertain. Thawing permafrost can intensify climate change effects, a point emphasized by experts who stress cautious interpretation of the evolving carbon cycle.
Scientists also observe that methane release from thawing permafrost could influence global warming in ways that differ regionally. In parts of Siberia, methane concentrations have been observed at levels well above atmospheric averages at depth in permafrost-related environments. This adds to the complexity of predicting future climate behavior. The challenge is not only the rate of melt but how rapidly and where gases escape and how ecosystems adapt.
The impact of thaw extends beyond climate. In countries like Switzerland, even a modest share of permafrost can lead to land instability, threatening buildings, pipelines, dams and other critical infrastructure. Experts warn that increasing rainfall and sediment movement may intensify landslides and sediment transport through rivers, an issue that will develop gradually but could carry significant costs and risk.
There remains a need for robust monitoring and adaptive planning to mitigate these effects across North America and other vulnerable regions. The ongoing research highlights the importance of understanding permafrost dynamics for policy, urban planning and public safety.