A farewell to glaciers: Ecosystem services loss in the Spanish Pyrenees.

Glaciers are long-term freshwater reservoirs that contribute to the regulation of water availability throughout the year. In the Pyrenees mountain range, glaciers are predicted to disappear by the mid 21st century if current melting trends continue. The areas downstream from these glaciers have seen a gradual increase in water consumption since the 1980s, mainly due to the conversion of traditional crops to more water-demanding products, expansion of the irrigated agricultural area, and modernization of agricultural techniques that create incentives to spread water use. The steady increase of water consumption is not compatible with the predicted future scenario, where a reduced provision of water as an essential ecosystem service is expected, in particular during the dry summers. In this study, we present an up-to-date outlook on the evolution of the glaciers on the Spanish side of the Pyrenees. We then calculate the melting rate (in volume) of these glaciers in order to estimate their water contributions to their respective watersheds. These results are combined with existing data on water consumption for each watershed, and aiming to offer a more sustainable future for the local population, we propose a set of adaptive measures that have been implemented in other regions where water availability has gradually become an issue. These measures are focused on diversifying the most water-consuming activity in the region (agriculture) to enable a future compatible with the ecosystem services the region is able to provide.