Seesaw‐Like Elevational Dependence of Permafrost Temperature Warming and Active Layer Thickening on the Qinghai–Tibet Plateau

Elevation‐dependent warming (EDW) is a well‐documented feature of climate change in mountain regions, yet how it influences elevation‐dependent permafrost change (EDPC) remains poorly understood. Here, we combine multiforcing ensemble simulations, a novel block‐sampling approach, and in situ observations to investigate regional EDPC on the Qinghai–Tibet Plateau (QTP) over the past four decades. The simulations reveal a robust seesaw‐like EDPC: In low‐elevation warm permafrost (3800–4600 m), active layer thickness (ALT) thickens more rapidly (−0.06 to −0.24 m 10a −1 per 1000 m), whereas in high‐elevation cold permafrost (4800–5600 m), temperature at the top of permafrost (TTOP) warms more rapidly (0.05°C–0.20°C 10a −1 per 1000 m). This pattern is consistently supported by observations from 54 permafrost stations, which show a similar temperature‐dependent seesaw relationship. We demonstrate that the seesaw‐like EDPC is dominated by subsurface surplus heat partitioning, governed primarily by initial permafrost temperature through the soil freezing characteristic curve, rather than by external EDW or local environmental factors. The pattern remains stable across the full range of historical and most projected future EDW scenarios, indicating that it represents a fundamental mode of alpine permafrost degradation. These findings provide a new thermodynamic framework for understanding regional permafrost change and highlight the critical role of internal heat partitioning in shaping the response of high‐mountain permafrost to climate warming.