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Abstract Over the past several decades, glacier retreat in the tropical Andes has accelerated. Given the role glacier melt plays for water supply, ecosystem integrity and glacier‐related natural hazards, improving projections of glacier changes in the region is critical. The accuracy of global climate models in this region remains an issue as the complex terrain and climate characteristics are difficult to realistically simulate. Here, we examine historical changes of freezing level height (FLH) on four tropical Andean glaciers: Antisana 15 glacier in Ecuador, Artesonraju glacier and Quelccaya ice cap in Peru, and Zongo glacier in Bolivia. The changes in FLH at each site are estimated based on ERA5 reanalysis data and then compared with historical simulations from 35 different CMIP6 models. Constraints are then placed on future projections via correction of model bias, selection of “best‐performing” models, and excluding models with an equilibrium climate sensitivity outside the Intergovernmental Panel on Climate Change AR6 likely range. By utilizing the significant empirical linear relationship observed between FLH and glacier equilibrium‐line altitude, we estimate the future shrinkage of the glaciers' accumulation zone under two emissions scenarios, SSP2‐4.5 and SSP5‐8.5. By the year 2100, the Quelccaya ice cap will likely have passed a point of no return, committing to losing its entire accumulation zone, regardless of emission pathway. The same is true for Antisana 15‐alpha glacier under SSP5‐8.5 while a small accumulation zone remains under SSP2‐4.5. Thanks to their higher accumulation area, Zongo and Artesonraju glaciers are more likely to survive beyond 2100, albeit in a strongly reduced extent.
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Glacier thickness and ice volume of the Northern Andes
Abstract Tropical glacier melt provides valuable water to surrounding communities, but climate change is projected to cause the demise of many of these glaciers within the coming century. Understanding the future of tropical glaciers requires a detailed record of their thicknesses and volumes, which is currently lacking in the Northern Andes. We calculate present-day (2015–2021) ice-thicknesses for all glaciers in Colombia and Ecuador using six different methods, and combine these into multi-model ensemble mean ice thickness and volume maps. We compare our results against available field-based measurements, and show that current ice volumes in Ecuador and Colombia are 2.49 ± 0.25 km 3 and 1.68 ± 0.24 km 3 respectively. We detected no motion on any remaining ice in Venezuela. The overall ice volume in the region, 4.17 ± 0.35 km 3 , is half of the previous best estimate of 8.11 km 3 . These data can be used to better evaluate the status and distribution of water resources, as input for models of future glacier change, and to assess regional geohazards associated with ice-clad volcanoes.
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- Award ID(s):
- 1759071
- PAR ID:
- 10397583
- Date Published:
- Journal Name:
- Scientific Data
- Volume:
- 9
- Issue:
- 1
- ISSN:
- 2052-4463
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1038/s41597-022-01446-8
