Yangyel Lhaden

As mountains become warmer due to global warming, scientists are probing a hidden threat beneath the surface—permafrost, the permanently frozen ground that, if thawed, could destabilise slopes, disrupt water systems, and release greenhouse gases.

For the first time, Bhutan’s National Centre for Hydrology and Meteorology (NCHM) is studying the presence of permafrost.

Supported by the International Centre for Integrated Mountain Development (ICIMOD), this study aims to understand an overlooked aspect of climate change in the Hindu Kush Himalaya region.

“To understand the impact of permafrost in our region, the first thing we need to know is whether permafrost is present in the country and, if so, how it is responding to the changing climate,” Karma, Chief of the Cryosphere Services Division, NHCM said. “This is a critical study, as the confirmation of presence of permafrost will allow us to conduct further research on the impact of climate change on permafrost and how it influences water resources, disaster risks and impacts on livelihood.”

Permafrost is defined as a ground which remains frozen for at least two years and is mostly found in cold regions like the Arctic, Antarctica, and high altitudes, covering 14 to 16 million square kilometres globally. It has long been a significant carbon sink, storing plant and animal remains.

However, as it thaws due to warming, this organic material decomposes, releasing greenhouse gases. Published literature also warns that thawing permafrost could unlock new viruses and diseases that have been buried for millions of years.

Permafrost thawing has significant implications for climate, livelihoods, and ecosystems. Globally, permafrost loss is comparable to the ice loss in Antarctica, with 150 billion tonnes of water melting annually. This melting could lead to a rise in sea levels, although the full impact is uncertain.

ICIMOD’s probabilistic mapping suggests a high likelihood of permafrost above 4,500 metres in Bhutan. NCHM’s pilot study, using this data, has installed 19 temperature sensors in the Yaree La area at the headwaters of Thim Chhu.

These sensors will monitor ground temperatures over two years. If readings consistently remain below 0°C, especially with slight summer increases, it will confirm the presence of permafrost.

“Depending on the success of this partnership, assessment and monitoring of permafrost will be extended to other parts of the country,” Karma said.

Lessons from the Arctic

Permafrost thawing has already disrupted Arctic communities, where about five million people live on permafrost-rich lands.

This region includes 1,162 settlements, most with fewer than 5,000 residents, while larger settlements, primarily in the Russian Arctic, house the majority of the population.

An account from Yakutia, Russia, highlighted in the Arctic Permafrost Atlas by GRID-Arendal and the Nunataryuk project partners, illustrates the impact. Permafrost underlies 80 percent of Yakutia, including the Yukaghir village of Nelemnoye, home to just 200 Yukaghirs, one of northeast Asia’s indigenous peoples.

Traditional practices like fishing, hunting, and reindeer herding are becoming dangerous or unviable as landscapes change.

In Yakutia, thawing permafrost is destabilising infrastructure and undermining centuries-old knowledge critical for survival in the tundra.

Implications for Bhutan

In Bhutan, permafrost is likely confined to altitudes above the country’s highest settlements, areas frequented by nomadic herders and cordyceps collectors. If confirmed, its thaw could disrupt local water supplies and livelihoods, significantly impacting these highland communities.

Bhutan is globally recognised as carbon-negative and committed to remaining carbon-neutral. However, current emissions assessments do not account for potential greenhouse gas emissions from permafrost thawing. If permafrost is confirmed in Bhutan, further studies could explore its role in greenhouse gas emissions, offering critical insights into how it might contribute to climate change.

Permafrost plays a crucial role in storing organic carbon, which remains locked in frozen ground.  When it thaws, microbial activity breaks down this organic matter, releasing potent greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Methane and nitrous oxide are especially potent, though short-lived, while carbon dioxide persists for thousands of years.

As warming accelerates, the active layer of permafrost—the seasonally thawing layer—thickens, increasing microbial decomposition and increasing greenhouse gas emissions. This creates a feedback loop where permafrost thaw contributes to global warming, which in turn accelerates further thawing.