Alpine grasslands, serving as a crucial ecological security barrier, have undergone significant change in response to rapid environmental changes. However, alpine grassland degradation and their sensitivity changes remain poorly understood. Here we used long-term satellite observations and a novel baseline to evaluate the grassland degradation status on the Northern Tibetan Plateau. Subsequently, sensitivity coefficients were employed to analysis sensitivity changes and the contribution of climate and human factors in grassland degradation. We observed a mitigation in grassland degradation, with soil moisture and livestock as the predominant contributing factor to this process. Additionally, alpine grasslands exhibit low sensitivity to environmental changes when vegetation cover is sparse but display high sensitivity when vegetation cover is abundant. Using path analysis, we show that sensitivity change pattern are caused by water variability. The sensitivity to climate change sharply increases with the increase in greening, indicating a potential trend of ‘greening but drought’ in the future.