Methane and carbon dioxide are leaking from thawing Arctic permafrost at accelerating rates, potentially adding nearly half a degree of warming to the planet by 2100. Scientists warn that the Arctic is warming four times faster than the global average, transforming the region from a carbon sink into a source of emissions.
Bubbles of methane are surfacing from the muck of Smith Lake in Alaska, a visible sign of a larger, invisible shift in the planet’s chemistry. This potent heat-trapping gas, created by the decomposition of plants and animals once locked in frigid ground, is escaping as the Arctic thaws. For millennia, the frozen earth acted as a global benefit by capturing more carbon than it released, but that balance has shifted.
Schuur describes this process as one of the scary tipping points
of climate change, noting that essentially every year is setting a permafrost record.
The Carbon Imbalance: Three Times More Frozen Than Airborne
The scale of the threat lies in the volume of stored organic matter. There is currently three times as much carbon frozen in permafrost as there is in the atmosphere. As this ground—defined as soil that remains below 32 degrees Fahrenheit (zero degrees Celsius) for at least two years and often for centuries or millennia—thaws, it releases gases that compound the warming already caused by the burning of fossil fuels.
This shift has effectively turned the Arctic into a contributor to the problem. According to Columbia University ecologist Duncan Menge, the region no longer reduces climate change but instead adds to it. This transition is part of a broader pattern of polar amplification, where Arctic latitudes warm significantly faster than lower latitudes.
Projected Warming: A Half-Degree Beyond Fossil Fuels
Researchers are now quantifying the specific temperature impact of these emissions. Two studies project that by the end of the century, gases escaping from permafrost will add nearly half a degree of warming—roughly a quarter-degree Celsius—on top of warming from human industrial activity. Scientists note this is equivalent to the warming impact of the entire European continent or the United States.
The impact may be underestimated in official projections.
Further compounding this is the risk of warming-induced emissions
from lakes, wetlands, and fires.
Alaska Soil Trends and the Role of Snow Cover
Recent data from Washington State University highlights that soil warming is occurring most rapidly in Alaska’s permafrost regions. A study analyzing soil temperatures in Alaska from 1997 to 2023 found that warming is occurring most quickly in the state’s permafrost regions.
- Depth Stability: Long-term warming trends were more obvious at depth. In permafrost regions, 100 percent of weather stations showed a warming trend at four feet deep, compared to only 65 percent at two inches.
- Winter Warming: Most warming in permafrost regions occurred during winter, which has direct consequences for infrastructure.
- Snow Buffering: In lower latitudes, deeper winter snow cover slows the rate of warming by providing a buffer against air temperature changes.
Thawing Ground Triggers Deadly Glacier Collapse in Nepal
The consequences of thawing extend beyond atmospheric chemistry to the physical stability of the earth. Permafrost provides the rigid foundation for roads, pipelines, and buildings in the Arctic. As it thaws, the ground collapses and sinks.
This instability can be fatal. This past summer, flooding in Nepal killed more than 1,000 people following a glacier collapse triggered by a record-setting heat wave. George Washington University scientist Dmitry Streletskiy suggests that the loss of frozen ground—which normally supports mountains and skyscrapers—was likely one of several factors in the disaster.