Increasing precipitation due to climate change could partially offset the impact of warming on glacier loss in the monsoon-influenced Himalaya until 2100 CE

Ann Rowan , Anya M Schlich-Davies, Andrew N Ross, Duncan J Quincey, Vivi K Pedersen

Glacier mass in the Himalaya is projected to shrink by 53 %–70 % due to climate change by 2100 CE. However, the impact of changes in precipitation amount and distribution on future glacier change remains uncertain because these variables are not often represented in glacier model projections. We explored the combined effects of past and future changes in air temperature and precipitation amount and distribution on the evolution of Khumbu Glacier in the Everest region of Nepal. We used a glacier modelling approach that forced an ice-dynamical glacier evolution model with surface mass balance calculations that included mesoscale meteorological variables derived from statistical downscaling of existing regional climate projections. Our simulations show that historical warming has committed Khumbu Glacier to mass loss of 10 %–23 % during this century, and that under an intermediate future emissions scenario (RCP4.5), this glacier could lose 70 % mass by 2100 CE due to warming. The projected increase in precipitation in tandem with warming could offset about half of the projected glacier loss, such that the total decrease in glacier mass by 2100 CE compared to the present day would be reduced to 34 %. However, under a higher future emissions scenario (RCP8.5) glacier loss due to warming will not be compensated by changes in precipitation, but will instead result in substantial ablation above 6000 m elevation, with devastating consequences for one of the highest glaciers on Earth.