Evolution of glacial lakes in Southern Patagonia Icefield between 1986 and 2023

Abstract

This study examines the distribution and temporal evolution of glacial lakes in the Southern Patagonian Icefield (SPI) between 1986 and 2023. The question addressed is how these lakes respond to climate change, and what risks of glacial lake outburst floods (GLOFs) may arise. Monitoring these lakes is crucial due to their connection with sudden glacial water release events and their potential impact on the region.   A combination of Landsat and Sentinel-2 satellite images was used to detect and analyze 313 glacial lakes in the 2023 inventory. Empirical models were applied to estimate lake area and volume, highlighting the non-linear relationship between area and volume. Additionally, temporal evolution was assessed by comparing inventories from 1986, 2000, and 2015-2023.   In 2023, 313 lakes were identified with a total area of 639.09 km² and a volume of 34.84 km³. The majority were moraine-dammed lakes (52.72%), followed by bedrock-dammed (24.28%), and ice-dammed lakes (23%). Moraine-dammed lakes exhibited continuous growth associated with glacier retreat, while bedrock-dammed lakes showed stability, and ice-dammed lakes displayed variability and a decrease in area and volume.   The evolution of glacial lakes in the SPI indicates a 34% increase in number, 29% in area, and 31% in volume between 1986 and 2023. GLOF events, especially in ice-dammed lakes, highlight the importance of continuous monitoring and risk assessment. The influence of external factors, such as extreme droughts, on glacier surface melt is emphasized. The non-linear relationship between area and volume underscores the importance of considering lake size when interpreting volume changes.