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

Glacial debris flows are prevalent across the southeastern Tibetan Plateau, driven by climate change-induced glacier retreat in this region. This retreat has facilitated an increased frequency of debris flow events, underscoring the need for a comprehensive understanding of their susceptibility to enhance hazard mitigation strategies. However, significant gaps remain in integrating climate change projections and glacier retreat dynamics into susceptibility assessments. This study presents a novel method for predicting the susceptibility of glacial debris flows under future climate change scenarios on the southeastern Tibetan Plateau. The proposed approach incorporates dynamic variables into susceptibility modeling, including annual precipitation, average annual temperature, projected glacier extents, and anticipated land cover changes. The analysis utilizes combined scenarios from Representative Concentration Pathways (RCPs) and Shared Socioeconomic Pathways (SSPs), specifically SSP1-2.6, SSP2-4.5, and SSP5-8.5, to evaluate the impacts of future climate conditions. Results indicate a notable increase in the number of glacier catchments with very high annual average temperatures from SSP1-2.6 to SSP5-8.5, particularly in the eastern portion of the study area, while annual precipitation exhibits minimal change. Land cover projections for 2030 suggest a shift from shrubland to bare land, signaling land degradation. Additionally, glacier retreat is evident, with a growing number of catchments projected to have a glacier area percentage below 0.05% by 2030. The susceptibility analysis reveals an increase in glacier catchments with high and very high susceptibility from SSP1-2.6 to SSP5-8.5. Notably, the number of catchments with very high susceptibility under SSP5-8.5 exceeds that of 2010 and closely resembles 2020 levels. These findings emphasize the escalating risks posed by climate change and glacier retreat, providing critical insights for developing adaptive hazard mitigation strategies in the region.