Worldwide glacier retreat and associated future runoff changes raise major concerns over the sustainability of global water resources^1,2,3,4, but global-scale assessments of glacier decline and the resulting hydrological consequences are scarce^5,6. Here we compute global glacier runoff changes for 56 large-scale glacierized drainage basins to 2100 and analyse the glacial impact on streamflow. In roughly half of the investigated basins, the modelled annual glacier runoff continues to rise until a maximum (‘peak water’) is reached, beyond which runoff steadily declines. In the remaining basins, this tipping point has already been passed. Peak water occurs later in basins with larger glaciers and higher ice-cover fractions. Typically, future glacier runoff increases in early summer but decreases in late summer. Although most of the 56 basins have less than 2% ice coverage, by 2100 one-third of them might experience runoff decreases greater than 10% due to glacier mass loss in at least one month of the melt season, with the largest reductions in central Asia and the Andes. We conclude that, even in large-scale basins with minimal ice-cover fraction, the downstream hydrological effects of continued glacier wastage can be substantial, but the magnitudes vary greatly among basins and throughout the melt season.

全球冰川的退缩和相关的未来径流变化引起了人们对全球水资源^1,2,3,4可持续性的重大关注，但是全球范围内对冰川消退和由此产生的水文后果的评估很少^5,6。在这里，我们计算了到2100年的56个大型冰川化流域的全球冰川径流变化，并分析了冰川对水流的影响。在大约一半的调查流域中，模拟的年度冰川径流继续增加，直到达到最大值（“峰值水”）为止，在此之前，径流稳步下降。在其余的盆地中，这个临界点已经过去了。高峰水出现在冰川较大，冰覆盖率较高的盆地中。通常，未来的冰川径流在夏初增加，但在夏末减少。尽管这56个盆地中的大多数冰川覆盖率不足2％，但到2100年，由于融化季节至少一个月内冰川质量损失，导致三分之一的径流减少量可能大于10％，其中最大的减少量是在中部地区。亚洲和安第斯山脉。我们得出结论，