Continuous mass loss acceleration of Qiangyong Glacier, southern Tibetan plateau, since the mid-1880s inferred from glaciolacustrine sediments

Abstract

Himalayan glaciers have been shown by satellite observations to be losing mass at accelerated rates since the mid-1970s, posing severe challenges to downstream water resource availability, ecological functioning, and glacial hazard prevention. Reconstructing long-term glacier fluctuations beyond the satellite era is consequently crucial to fully understand this acceleration. However, glacier reconstructions in the Himalayas are mainly based on discontinuous moraine chronologies, with the most recent ones marking only the timing and position of the Little Ice Age (LIA; 1250–1850 CE) maxima of Himalayan glaciers. Here, we reconstruct continuous records of the activity of Qiangyong Glacier, southern Tibetan Plateau, since the onset of the LIA (1316–2004 CE) and associated variation in precipitation, by retrieving glacier melting and advancing signals from grain size and analysing leaf wax hydrogen isotopes in the same glaciolacustrine sediments. We show that the glacier was relatively stable during the LIA, with its terminus shifting within ∼100 m, depending on the combined effects of precipitation and temperature. However, it retreated by ∼150 m under maximum precipitation conditions at the end of the LIA (approximately 1845–1866 CE) and, most importantly, has exhibited accelerated mass loss since the mid-1880s. Comparisons with regional and Northern Hemisphere temperatures suggest that climate warming rather than decreased precipitation since the end of the LIA plays a primary role in driving this accelerated mass loss. Our glaciolacustrine record add a continuous perspective on the variability of Himalayan glaciers, especially their mass loss status since the end of the LIA.