• Energy Research

3 Pags. The definitive version is available at: https://www.sciencedirect.com/science/journal/03014797 The authors want to acknowledge funding by the projects Capitalización, observación, transferencia y apropiación de estrategias de adaptación al cambio climático en los Pirineos en un contexto de cooperación transfronteriza. ADAPYR: OPCC3 and EFA210/16-PIRAGUA, both co-founded by the European Regional Development Fund (ERDF) through the Interreg V Spain-France-Andorre Programme (POCTEFA 2014–2020) of the European Union; INNOMED, co-funded by the Agencia Estatal de Investigación of Spain in the framework of the ERA-NET WaterWorks2015 cofunded Call (project INNOMED); Cross-sectoral impact assessment of droughts in complex European basins-CROSSDRO funded by ERANET-AXIS Joint Call for Transnational Collaborative Research and “El papel de la nieve en la hidrología de la península ibérica y su respuesta a procesos de cambio global- CGL 2017-82216-R” funded by the Spanish Ministry of Economy. Peer reviewed

The Aneto Glacier, is the largest glacier in the Pyrenees. Its shrinkage and wastage have been continuous in recent decades, and there are signs of accelerated melting in recent years. In this study, changes in the surface and ice thickness of the Aneto Glacier from 1981 to 2022 are investigated using historical aerial imagery, airborne LiDAR point clouds, and UAV imagery. A GPR survey conducted in 2020, combined with data from photogrammetric analyses, allowed us to reconstruct the current ice thickness and also the existing ice distribution in 1981 and 2011. Over the last 41 years, the total glaciated area has shrunk by 64.7% and the ice thickness has decreased, on average, by 30.5 m. The mean remaining ice thickness in autumn 2022 was 11.9 m, as against the mean thicknesses of 32.9 m, 19.2 m reconstructed for 1981 and 2011 and 15.0 m observed in 2020 respectively. The results demonstrate the critical situation of the glacier, with an imminent segmentation into two smaller ice bodies and no evidence of an accumulation zone. We also found that the occurrence of an extremely hot and dry year, as observed in the 2021–2022 season, leads to a drastic degradation of the glacier, posing a high risk to the persistence of the Aneto Glacier, a situation that could extend to the rest of the Pyrenean glaciers in a relatively short time. Peer reviewed