Assessment of Glacier Transformation in China over the Past 40 Years Using a China-Specific Glacier Classification System

Glacier classification offers a structured framework for assessing and managing glacier resources, while understanding the responses of different glacier types to climate change is essential for revealing glaciological dynamics. In this study, we apply the China-specific Shi-Xie glacier classification system to systematically evaluate the transformation of extremely-continental, subcontinental, and maritime glaciers across China over the past four decades. Our results show a widespread rise in equilibrium line altitudes (ELAs), alongside complex changes in climatic and glaciological parameters. Notably, despite ongoing warming trends, nearly half of the glaciers experienced cooling at the ELA, and over two-thirds showed a decline in summer temperatures. Near-surface ice temperatures (20 m depth) were strongly consistent with changes in annual air temperature. Precipitation trends were regionally heterogeneous, yet around 70% of glaciers experienced stable or slightly increasing annual precipitation. In contrast, maritime glaciers particularly those in the southeastern regions such as the Hengduan Mountains exhibited marked decreases. Glacier velocities generally declined, with 90% of glaciers flowing at speeds below 50 meters per year. An analysis of classification threshold deviations reveals that glaciers in transitional zones frequently exhibit multi-indicator shifts. Extremely-continental glaciers near classification boundaries show signs of shifting toward warmer, wetter subcontinental conditions, while maritime glaciers tend to evolve toward drier, colder subcontinental characteristics. These findings offer new insights into the differentiated responses and ongoing transformation of glacier types in China under climate change.