The Arctic‘s frozen carbon is waking up, and it is warming the world

On the edges of Smith Lake in Alaska, the ground is no longer as solid as it once was. Ted Schuur, an ecologist at Northern Arizona University, walks along the muck and watches bubbles rise to the surface—one after another, like a slow exhale from the earth itself. The bubbles contain methane, a potent greenhouse gas produced by decomposing plants and animals that had been frozen in permafrost for thousands of years. The ground is thawing, and the gas is escaping.

Permafrost is ground that stays frozen for at least two years, and often for centuries or millennia. It covers vast areas of Alaska, Canada, Siberia, and the high mountains of Asia. Within it, dead plant and animal matter has been locked away, prevented from decaying by the cold. Scientists estimate that permafrost contains about three times as much carbon as is currently in the atmosphere. As the Arctic warms—four times faster than the rest of the globe—that frozen ground is beginning to lose its grip on that carbon.

The release of methane and carbon dioxide from thawing permafrost is one of the climate system‘s most closely watched feedback loops. It is a process that, once started, cannot easily be stopped. “Once you start leaking this carbon out, there’s so much in the ground that it‘s not going to shut off,” Schuur said, describing it as one of climate change’s scary tipping points. Each year, he noted, seems to set a new permafrost record.

The numbers are significant. Two studies project that by the end of this century, greenhouse gases released from thawing permafrost will add nearly half a degree Celsius of additional warming, on top of the warming caused by burning fossil fuels. That is roughly equivalent to the emissions of a major industrialized country like the United States, or the entirety of Europe. The Arctic, which for thousands of years acted as a carbon sink—absorbing more carbon than it released—has now shifted into a source, adding to the problem rather than mitigating it.

What makes this particularly challenging is that current climate policies and projections often do not account for permafrost emissions. When the United Nations estimates future warming, the extra greenhouse gases from thawing permafrost are typically left out of the calculations. The result is that the trajectory we are on may be slightly worse than the official numbers suggest—a few tenths of a degree here, a few there, accumulating over decades.

Thawing permafrost is not only a climate problem. It is also a problem of infrastructure and stability. Ground that has been frozen for centuries is no longer strong enough to support buildings, roads, and pipelines. In some places, the land is collapsing and sinking, a process that scientists call thermokarst. The destabilization is already affecting communities in the Arctic, and it is likely to worsen.

The bubbles rising from Smith Lake are small, almost insignificant in isolation. But they are part of something larger—a slow leak from a vast reservoir of carbon that has been sealed for millennia. The Arctic is warming, the ground is thawing, and the gas is escaping. The process is underway, and its effects will be felt far beyond the shores of a single Alaskan lake.

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AI Image Disclaimer: The images in this article were created with artificial intelligence tools and are for illustrative purposes only.

Sources: Associated Press, La Nación, IPCC