Projections of the future disappearance of the Quelccaya Ice Cap in the Central Andes

• Published in: Scientific Reports
• Main Authors: Yarleque, Christian, Vuille, Mathias, Hardy, Douglas, R, Timm, Oliver, Elison, de La Cruz, Jorge, Ramos, Hugo, Rabatel, Antoine
• Other Authors: State University of New York (SUNY), University of Massachusetts Amherst (UMass Amherst), University of Massachusetts System (UMASS), Universidad Nacional Agraria La Molina (UNALM), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDE.MCG]Environmental Sciences/Global Changes; Ice cap
• Online Access: https://hal.science/hal-01901754; https://hal.science/hal-01901754/document; https://hal.science/hal-01901754/file/Yarleque2018NatureSR.pdf; https://doi.org/10.1038/s41598-018-33698-z

International audience We analyze the future state of Quelccaya Ice Cap (QIC), the world's largest tropical ice cap with a summit elevation of 5680 m a.s.l., which, in terms of its elevation range (~5300-5680 m a.s.l.), is representative of many low-elevation glacierized sites in the tropical Andes. CMIP5 model projections of air temperature (Ta) at QIC indicate a warming of about 2.4 °C and 5.4 °C (respectively) for RCP4.5 and RCP8.5 scenarios by the end of the 21 st century, resulting in a pronounced increase in freezing level height (FLH). The impact of this warming on the QIC was quantified using equilibrium-line altitude (ELA) projections. The change in the ELA was quantified based on an empirical ELA-FLH relationship, and calibrated with observations of the highest annual snowline altitude (SLA) derived from LANDSAT data. Results show that from the mid-2050s onwards, the ELA will be located above the QIC summit in the RCP8.5 scenario. At that time, surface mass balance at QIC and most tropical glaciers at similar elevations will become increasingly negative, leading to their eventual complete disappearance. Our analysis further corroborates that elevation-dependent warming (EDW) contributes significantly to the enhanced warming over the QIC, and that EDW at Quelccaya depends on the rate of anthropogenic forcing.