Long-range transport of black carbon from South Asia to the Tibetan plateau and its deposition on glaciers directly enhances glacier melt. Here we find South Asian black carbon also has an indirect effect on the plateau’s glaciers shrinkage by acting to reduce the water supply over the southern Tibetan plateau. Black carbon enhances vertical convection and cloud condensation, which results in water vapor depletion over the Indian subcontinent that is the main moisture flux source for the southern Tibetan plateau. Increasing concentrations of black carbon causes a decrease in summer precipitation over the southern Tibetan plateau, resulting in 11.0% glacier deficit mass balance on average from 2007 to 2016; this loss rises to 22.1% in the Himalayas. The direct (accelerated melt) and indirect (mass supply decrease) effects of black carbon are driving the glacial mass decline of the so-called “Asian Water Tower”.

黑碳从南亚向青藏高原的远距离输送及其在冰川上的沉积直接促进了冰川融化。在这里，我们发现南亚黑碳通过减少青藏高原南部的供水量，对高原冰川收缩也有间接影响。黑碳增强了垂直对流和云凝结，导致印度次大陆上空的水汽枯竭，而印度次大陆是青藏高原南部的主要水分通量来源。黑碳浓度的增加导致青藏高原南部夏季降水减少，导致2007年至2016年冰川物质平衡平均下降11.0%；在喜马拉雅山，这一损失上升到 22.1%。