Dynamic susceptibility assessment of glacial debris flows on the southeastern Tibetan plateau under future climate change scenarios

Glacial debris flows are prevalent on the southern Tibetan Plateau because climate change has caused the retreat of glaciers in this region. As a result, the occurrence frequency of debris flows has increased. Therefore, understanding the susceptibility of glacial debris flows is crucial for effective hazard mitigation. However, limitations still exist in integrating climate change and glacier retreat for forecasting the occurrence of debris flows. This study presents a method for predicting glacial debris flow occurrence on the southeastern Tibetan Plateau under future climate scenarios, incorporating dynamic variables such as annual precipitation, annual average temperature, projected glacier extents, and anticipated land cover changes. In this study, combined scenarios of representative concentration pathways and shared socioeconomic pathways (including SSP1-2.6, SSP2-4.5, and SSP5-8.5) were used to assess the impacts of future climate change on the occurrence probability of glacial debris flows. The projected land cover map in 2030 indicates that a greater proportion of forested areas are projected to be converted into grassland, suggesting ongoing land degradation. The glacial debris flow susceptibility map for 2030 indicates that the number of catchments with very high susceptibility under SSP5-8.5 is greater than that under SSP1-2.6 and SSP2-4.5. The number of glacier catchments with very high glacial debris flow susceptibility under SSP5-8.5 increased by 41% and 10% compared with the number of glacier catchments with very high glacial debris flow susceptibility under the SSP1-2.6 and SSP2-4.5 scenarios, respectively. These findings provide critical insights into the links between climate change and glacial debris flow susceptibility, informing land-use planning and geohazard management on the southeastern Tibetan Plateau.