Urbanisation and forest fires are increasing across the western and central Himalaya, enhancing air pollution and deposition of light-absorbing aerosols on snow and ice. While rising temperatures drive glacier retreat, the role of aerosols, including black carbon, dust and organic carbon, in accelerating melt remains poorly constrained. Current projections rely on empirical melt factors that neglect aerosol-driven snow darkening, leading to underestimated hydrological risks.

This project quantifies aerosol-induced melt amplification and its implications for water availability using coordinated observations and modelling across five glacierised catchments in India, Nepal and Bhutan. Measurements of atmospheric aerosols, snow deposition, radiation (direct/diffuse) and high-elevation temperature will constrain aerosol-aware enhanced degree-day factors (DDF_EF). These will be integrated into PyGEM and PyGDM models to assess impacts on melt timing, peak flows, late-season water availability, glacier change over the next 50 years and seasonal discharge.

Scenario analyses will evaluate how reducing aerosol loading can mitigate melt and improve water security. The project adopts a transboundary approach with targeted training and shared tools, providing actionable knowledge for water security, climate adaptation and air quality management across the Himalayan region.