The editors of Nature have become aware that this Article contains an error in the use of mass imbalance data. Specifically, the author used mass imbalance data from table 2 in ref. 32 described as decadal averages (millimetres water equivalent) that are in fact annual values averaged over a decade (millimetres water equivalent per year). The specific numbers presented for the net melt fraction and affected population are therefore incorrect, and probably underestimated. Nature is working with the author to address the error, but in the meantime, readers are cautioned against using the paper’s quantifications. The author agrees with our expression of concern. We thank L. Zhao and J. Moore for bringing the error to our attention on 2 June 2017.