Sensitivity of Permafrost Degradation to Geological and Climatic Conditions

Abstract

Permafrost degradation varies spatially; however, the underlying mechanism remains partially unclear. In this study, we predicted permafrost variation under the influence of climate change to investigate the sensitivity of permafrost degradation to geological and climatic conditions. The results revealed that geological strata can strongly impact the permafrost degradation process. Mainly due to the greater thermal conductivity of sandy gravel in the Arctic, the complete thaw of permafrost will be greatly delayed by more than 160 years compared with that on the Qinghai–Tibet Plateau (QTP). Climatic conditions, such as snow depth, can also greatly affect the degradation process of permafrost: The thaw of permafrost will be delayed by more than 140 years when the snow depth decreases from 0.7 to 0.1 m. Peat soil thickness at ground surface can also affect permafrost degradation. The permafrost temperature increases as peat soil thickens when the thickness is less than 1.0 m, whereas there is a critical peat soil thickness (approximately 0.2 and 0.5 m on the QTP and in the Arctic, respectively) under which permafrost will thaw at the fastest rate. The findings highlight the influence of geology and climate over permafrost degradation.