Ice velocity and thickness of the world's glaciers

The effect of climate change on water resources and sea-level rise is largely determined by the size of the ice reservoirs around the world and the ice thickness distribution, which remains uncertain. Here, we present a comprehensive high-resolution mapping of ice motion for 98% of the world's total glacier area during the period 2017-2018. We use this mapping of glacier flow to generate an estimate of global ice volume that reconciles ice thickness distribution with glacier dynamics and surface topography. The results suggest that the world's glaciers have a potential contribution to sea-level rise of 257 +/- 85 mm, which is 20% less than previously estimated. At low latitudes, our findings highlight notable changes in freshwater resources, with 37% more ice in the Himalayas and 27% less ice in the tropical Andes of South America, affecting water availability for local populations. This mapping of glacier flow and thickness redefines our understanding of global ice-volume distribution and has implications for the prediction of glacier evolution around the world, since accurate representations of glacier geometry and dynamics are of prime importance to glacier modelling. Potential sea-level rise from the world's glaciers is 20% less than previously thought, according to an estimate based on high-resolution maps of glacier ice velocity and thickness.

Automated summary

This study provides high-resolution mapping of ice motion and thickness for glaciers worldwide, and estimates the global ice volume. The results show that the contribution of world's glaciers to sea-level rise is 20% less than previously thought. Additionally, there are notable changes in ice resources in low latitude regions, with an increase of 37% in the Himalayas and a decrease of 27% in the tropical Andes of South America, which affects water availability for local populations.