Mitigating future glacial lake outburst floods in the Himalaya

Glacial lake outburst floods (GLOFs) are among the most severe cryospheric hazards in the Himalaya. While previous studies have primarily focused on the characteristics and causes of GLOFs, strategies for mitigating their disaster impacts remain underexplored. This study introduces China's Glacial Lake Management System (GLMS) and evaluates its potential for regional replication in reducing damage caused by GLOFs. We find that while GLOF frequency shows a statistically insignificant decrease from 1990 to 2023, downstream damage has intensified, yet appears relatively mitigated within China across the Himalaya following the implementation of the GLMS. Further hydrodynamic modelling suggests that glacial lakes will continue to expand in the future, with total growth expected to triple relative to the 2000-2020 period. These expansions could increase GLOF exposure by over 27% for high-risk lakes and by more than 40% in regions outside China without targeted interventions. However, implementing GLMS engineering measures could reduce the intensity of future floods by 24%, with even greater reductions outside China-29% compared to 21% within China. Building on China's lake management experience and recognizing the transboundary nature of GLOFs, the comprehensive framework we propose for region-wide glacial lake risk reduction across the Himalaya integrates engineering measures, early warning systems, and community responses. This framework addresses the urgent need for proactive and coordinated mitigation strategies in densely populated high-mountain regions.