The 2010–2020 'megadrought' drives reduction in lake surface area in the Andes of central Chile (32º - 36ºS)

Study region: Andes central Chile (32ºS-36ºS) / Lakes Study focus: Mountain lakes play a key role in the terrestrial freshwater reservoir, both for storage of snow melt and precipitation. Although lakes are sensitive to climate variability, the effect of global warming on water availability remains uncertain. Semiarid regions are especially sensitive to relatively small changes in temperature and precipitation as these have disproportionately large impacts on lake hydrologic budgets. Here, we mapped 12 lakes from the Andes of central Chile (32º-36ºS) using Landsat mission and Sentinel-2 satellites images from 1984 to 2020 and compared these results with the available climate data (precipitation, temperature, and evaporation). New hydrological insights for the region: This approach provides a high-resolution temporal and spatial analysis for changes in lake surface over the last 36 years. Our results indicate that the number of lakes and respective surface area decrease latitudinally from south to north across central Chile, which is consistent the present-day rainfall gradient. Over the study period, lake surface areas decreased significantly between 7% and 25% during the so-called ‘megadrought’ (2010–2020). As lakes continue to dry up, the implications for freshwater availability are of considerable societal and environmental importance. Our results can assist with water management decisions and improve our understanding of future water availability across the region.