Glacial hazards change in Xinjiang over the past seven decades: Spatiotemporal patterns and trends

Glacier hazards caused by global warming and glacier retreat have disastrous consequences for communities in high mountain regions. Research on the distribution patterns and development trends of glacier hazards is essential for improving the understanding of glacier hazards and mitigating disaster risks in high mountains. This study systematically analyses the types, spatial, and temporal variations of glacier hazards attributed to the impacts of climate change and glacier retreat in the Tianshan, Pamir, Karakoram and Kunlun Mountain ranges in Xinjiang between 1950 and 2020. Climatic conditions and glacier surveys (including glacier fronts and mass balance measurements) are used as drivers to analyse spatial and temporal patterns of glacier hazards. The results indicate that 330 glacial hazards occurred in Xinjiang, the majority of which were in the Tianshan and Karakoram regions. Glacial hazard numbers decelerated, while temperature rise accelerated over the past seven decades. From 1950 to 2000, glacier hazards increased at an average rate of 0.74 each year, whereas, after 2000, they decreased at an average rate of 0.82 per year. Glacier surges have increased since 1990 in the Pamir-Karakoram Mountains and the Kunlun Mountains. Glacier surges in the Pamir-Karakoram Mountains exhibited the highest activity from 1990 to 1999 and 2000 to 2009. The annual occurrence of glacier outburst floods has decreased since the early 2000s, while the flood peak discharges of glacial lake outburst floods (GLOFs) has intensified in Tianshan. Glacier debris flows in the Pamir and Tianshan mountain regions increased after 2010, frequently occurring on the Tianshan Highway and the China-Pakistan Karakoram Highway during the summer months. Glacier debris flows originated above 4,500m above sea level (a.s.l.), but most hazards occurred between 2000 and 3,000m a.s.l. In Xinjiang, glacier debris flows pose the greatest threat in the central and high mountain regions and require close attention. Temperature is the primary influencing factor driving trend changes and spatiotemporal patterns of glacial hazards. The hazard occurrence rates are uncorrelated with rainfall and glacier dynamics. Therefore, in adapting to climate change, it is crucial to consider the spatiotemporal variation of glacial hazards and their influencing factors in high mountain regions to provide a scientific basis for exploring the predictability, prevention, and mitigation of disasters.