Measuring glacial sustainability using glacial mass balance at Baspa Basin, India

Abstract Abiotic ecosystem services (ES) such as water provisioning, climate regulation, hydropower energy production and other non-living benefits are under threat due to glacier retreat in the Baspa Basin, Indian Himalayan Region (IHR). Perspective analysis of these challenges at ground level indicated the immediate need to align climatological assessments with the sustainability indicators. Glacier mass balance estimates using a combination of geospatial modelling and an empirical IAAR method showed continuous mass loss from 1995 till 2022 with a cumulative mass loss of 1.2 ± 0.4 Gt, evidencing multi-scale hydrological imbalance of IHR. A water loss of 19% was observed during 1985 and 2022 due to melting. The results demonstrate substantial heterogeneity in glacier responses across the basin, indicating that glacier behaviour is governed not only by regional climatic variability but also by local topographic factors. The concept of unit of Glacier Sustainability provides a new and useful framework for understanding basin-scale glacier dynamics and offers a systematic approach for identifying glacier groups with similar stability or vulnerability patterns. It refers to glaciers exhibiting comparable mass balance trends, ELA sensitivity, accumulation conditions, and retreat characteristics under shared climatic and topographic controls. This framework can support improved assessment of glacier change and hydrological implications in other glacierized basins across the Himalayas.