Glaciers in High Mountain Asia (HMA) provide meltwater crucial for 250 million people. This study uses altitudinally-resolved specific mass balances (SMB) for 5527 glaciers (2000–2016) to assess their health and sustainability. Results show that only 60% of annual ablation was compensated by accumulation. Even without 21st-century warming, 21% of ice volume will be lost by 2100 due to current imbalance, reducing river ablation by 28%. Himalayan and Tien Shan glaciers are largely unsustainable, facing at least 30% ice volume reduction by 2100. Major glacier-fed river basins will see long-term meltwater supply reductions, despite the Karakoram Anomaly.

Evan Miles, Michael McCarthy, Amaury Dehecq, Marin Kneib, Stefan Fugger, Francesca Pellicciotti