Warming‒wetting and continentality co-modulate the effect of desertification on permafrost degradation on the Qinghai‒Xizang Plateau

Permafrost degradation and desertification have been identified as two major land surface processes occurring on the Qinghai‒Xizang Plateau. However, the effect of desertification on permafrost degradation remains poorly understood. In this study, land surface process simulations are used to demonstrate that climate change, characterised by increased warming‒wetting trends alongside reduced continentality, plays a primary role in how desertification mitigates permafrost degradation. This mitigating effect is co-modulated by the two aspects of climate change, which affect the seasonal thermal resistance of aeolian sand and its weak heat absorption capacity. Overall, with the simultaneous increase in the warming‒wetting rate and the reduction in continentality, the mitigating effect of desertification on permafrost degradation is projected to intensify by 57.6% and 99.6% under the SSP2-4.5 and SSP5-8.5 scenarios, respectively. Therefore, permafrost degradation in desertified regions of the plateau will be more effectively mitigated. This conclusion may also be applicable to other regions where permafrost and desert conditions coexist, such as parts of Russia. This study presents a novel scientific perspective on the climate dependency of desertification’s effect on permafrost degradation and provides valuable insights for predicting ecological changes and developing targeted environmental protection policies in plateau regions.