The state and fate of Glaciar Perito Moreno Patagonia

Abstract

Glaciar Perito Moreno, located in the Southern Patagonian Icefields, has long been considered stable despite widespread regional glacier retreat. Unlike neighboring glaciers, its frontal position and surface elevation remained relatively unchanged - until recently. For lake-terminating glaciers, retreat is strongly controlled by their basal topography, which remains poorly known for Glaciar Perito Moreno. Here, we present helicopter-borne ground-penetrating radar and bathymetric data, along with time series of surface elevation and velocity. We detect an acceleration in frontal surface lowering rates, from 0.34 m a−¹ (2000–2019) to 5.5 m a−¹ (2019–2024), accompanied by glacier acceleration and retreat. Using a simple numerical model projecting current thinning into the future, we demonstrate the potential for large scale buoyancy-driven retreat once the glacier recedes beyond a subglacial ridge. These findings reveal a high sensitivity to frontal dynamics and suggest that Glaciar Perito Moreno may now be following a similar pattern of other retreating lacustrine calving glaciers in Patagonia.