Predicted thermal state of ground in South Yakutia under vegetation cover disturbance and climate warming

In recent years, cryogenic processes have been actively intensifying across the Sakha Republic (Yakutia), particularly in disturbed landscapes as a consequence of modern climate warming, evidenced by the rise in mean annual air temperatures since the late 1980s. The intensification of cryogenic processes affects the population’s quality of life primarily the stability of engineering structures and the environmental risks associated with potential accidents. South Yakutia lies within a zone of discontinuous permafrost, where numerous industrial facilities are concentrated. This article examines the results of predictive modeling regarding the geocryological conditions of South Yakutia under scenarios of climate warming and vegetation cover disturbance, specifically due to catastrophic fires and logging in mountainous taiga and sparse-forest areas. The study focuses on the active layer thickness and permafrost temperature within typical South Yakutia landscapes, specifically on sites underlain by loamy deluvium on gentle slopes and by stony-rubbly deposits on flat upland areas. Predictive modeling conducted for a 20-year period covering the Upper Amga, Tommot, and Chulman sites, taking into account current trends of rising mean annual air temperatures. Predictive modeling indicates that a combination of factors an increase in mean annual air temperature of 0.02°C per year and the loss of vegetation cover will cause the upper layer of permafrost to thaw to a depth of 5–9 meters and ground temperatures to rise by 1.2°C, thereby triggering subsidence and landslide processes. Calculations suggest that maximum thaw depths will occur in the rocky soils of slopes and plateau areas, a phenomenon attributed to their thermophysical properties.

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