Andean glaciers are some of the least understood and least modelled glaciers, despite being a crucial component of Andean water towers. Glaciers across the Andes have lost ~25% of their area since the Little Ice Age, while global-scale ice-models predict ~90% ice loss by 2100 CE under the highest emission scenarios. These global-scale ice-models, however, are limited in their utility for regional projections, due to their use of; i) limited mass-balance observations over Andean glaciers that can provide model-data calibration; ii) downscaled global climate models, which are poor at capturing the climatology over mountains; and iii) simplified ice-flow and mass balance processes.

As part of the Deplete and Retreat: The Future of Andean Water Towers project, we aim to develop a modelling framework which overcomes these challenges. We will combine the use of high-resolution dynamically downscaled climate data and COSIPY, a snowpack and ice surface energy and mass balance model, to produce time varying glacial surface mass balance and temperature fields. These are used to force the Parallel Ice Sheet Model (PISM) to produce high resolution ice-flow simulations of past, present, and future ice mass changes in hydrologically important catchments over the Andes.

Here, we present our initial completion of this modelling framework over the Cordillera Vilcanota region. We present time transgressive model outputs, compared against their LIA and present day ice extents to ensure the model is accurately capturing already observed ice changes. This is then forced into the future with mass balance and temperature fields generated under different emission scenarios to project the status of glacier ice in 2150 CE. Future work will expand our approach to other catchment areas that span the Andes, to project glacier changes in a warming world and understand the future implications for water towers.