Glacier mass loss on the southeastern Tibetan Plateau since the Little Ice Age

Maritime glaciers on the southeastern Tibetan Plateau (SETP) are experiencing rapid mass loss, yet both current rates and future projections lack centennial-scale context. Here, we mapped the outlines of 2454 glaciers at their Little Ice Age (LIA) maximum (~1300–1700 CE) on the SETP and reconstructed their thickness. The results show that there has been a 21.5% reduction in area and a loss of 152.9 km³ of ice (130 Gt) since the LIA at a rate of 0.19–0.43 Gt year⁻¹. We estimated the long-term average mass balance of glaciers to be between −0.028 and −0.065 m water equivalent (w.e.) year⁻¹. The rate of change between 2000 and 2019 CE was 10 to 23 times higher than LIA maximum to 2000 CE, far exceeding any centennial-scale rates of change recorded elsewhere in the world. Locally, lake-terminating glaciers lost mass faster than land-terminating glaciers. Spatial trends in the rate of glacier mass loss and the extent of equilibrium-line altitude (ELA) changes on the SETP are influenced by glacier size, as well as the topography and climate of the study area. Glaciers in the lowland of river valleys such as the Yarlung Zangbo-Brahmaputra show slower mass loss and larger ELA changes. The significant spatial heterogeneity of glacier change suggests that glacier evolution is influenced by both regional and local factors.