Year-round frozen ground at 3,500m elevation. Borehole temperature measurements show it's warming at 0.2°C per decade, 5 times faster than the air above it.
An invisible climate indicator
In the high altitudes of the Chatkal Range, a part of the Western Tian Shan mountains, a significant climatic shift is occurring deep within the ground. This region contains alpine permafrost—patches of earth and rock that remain at or below 0°C for at least two consecutive years. Located on steep, north-facing slopes above 3,200 meters, this permafrost is an important, albeit largely unseen, component of the mountain ecosystem. The range itself is a formidable barrier of granite, limestone, and schist, with peaks reaching up to 4,503 meters.
Scientific monitoring in the broader Tien Shan mountains reveals a clear warming trend. Boreholes drilled into the frozen ground provide direct temperature measurements, showing that the permafrost is warming at a rate of 0.2°C per decade. This is approximately five times faster than the observed warming rate of the air in the same region. This accelerated ground warming points to interactions between the atmosphere, snow cover, and subsurface geology. Increased winter snow can insulate the ground, trapping geothermal heat and preventing the deep cold of winter from penetrating, which paradoxically leads to warmer permafrost temperatures over time.
Thawing ground, uncertain future
the effects of this rapid warming are multifaceted. As the permafrost thaws, the "active layer"—the upper layer of ground that thaws in summer and refreezes in winter—deepens. In the Northern Tien Shan, the active-layer thickness has increased by an average of 20-25% since the 1970s. This process can destabilize mountain slopes, as the ice that once cemented soil and rock together melts. The degradation of permafrost increases the risk of natural hazards such as landslides and rockfalls.
This thawing also affects water resources in an already arid region. The Chatkal Range is a primary watershed for the Chirchik river, which supplies water to the Tashkent region. Permafrost is an impermeable layer, influencing how meltwater from glaciers and snow moves through the landscape. As it thaws, regional hydrological patterns change, affecting the timing and volume of water available downstream. Thawing permafrost can also release greenhouse gases like methane and carbon dioxide that were previously locked in the frozen soil, contributing to further atmospheric warming. Continued monitoring in remote locations like the Chatkal Range is essential for understanding the pace of these changes.
💡Fun Facts
The Tien Shan mountain system, of which the Chatkal Range is a part, is one of the largest active intracontinental mountain belts in the world.
The geology of the Chatkal Range is composed of ancient limestone from the Upper Devonian and Lower Carboniferous periods, along with granite and schist.
The range is an important watershed, feeding major rivers like the Syr Darya and influencing the water supply for millions of people in the Fergana Valley.
Below 3,500 meters, the mountain slopes host diverse fauna, including wild boars, foxes, bears, and the forest dormouse.
This is a remote, high-altitude scientific monitoring area and is not accessible to the public.
Admission
Not applicable.
Accessibility
Access is by expedition only, requiring off-road vehicles and extensive mountaineering. The terrain consists of steep, rocky slopes at high elevations.