An assessment of climate change impacts on glacier mass balance and geometry in the Chandra Basin, Western Himalaya for the 21st century

Abstract

The Himalayan glaciers are a major source of Perennial River systems in South Asia and the retreat of these glaciers under climate change could directly affect millions of people who depend on them. In this study, we assess the glacier mass balance, area and volume changes at basin scale for the Chandra Basin in the western Himalaya due to projected climate change in the 21st century. The Chandra basin occupies ∼2440 km² of area and hosts ∼200 glaciers and 23 small villages. The multi-model projections used in this study indicate a temperature increase of 2.2 °C–2.9 °C and 4.3 °C–6 °C for the RCP 4.5 and RCP 8.5 scenarios by the end of the century with a steady or decreasing trend in snowfall in the basin. In response to the projected climate, the basin is likely to retain only 50%–52% (RCP 4.5) and 40%–45% (RCP 8.5) of the areal extent of glaciers by the end of the century. Corresponding volumes of glacier water retained are much lower at 40%–43% and 29%–34%, but the volume loss could be as high as 97% for low altitude glaciers. Overall, our study highlights the likely severe impacts to water resources in the Himalaya if CO₂ emissions follow the high-emission scenario of RCP8.5.