El Perito Moreno glacier, in Argentine Patagonia, shows clear signs of a accelerated retreat that had not been observed in decades. New scientific evidence suggests that if the ice loses the support it still retains under its forehead, a very rapid withdrawal could be triggered into the lake.
With about 30 kilometers long and fed by the Southern Patagonian Ice Field, this glacier flows into the Argentino lake and is recognized as Heritage since 1981. For years it was cited as one of the most stable glaciers in the region, a trait that is now changing rapidly.
What the new research says
Equipment researchers from Argentina and Germany has published a detailed analysis of the status of the Perito Moreno in the journal Communications Earth & Environment (Nature Portfolio). The work combines radar campaigns carried out from a helicopter in March 2022 with series of satellite data spanning from 2000 to 2024.
In addition to measuring the ice thickness, scientists mapped the lake bed ahead of the front and reconstructed the evolution of the height and speed from the surface. This high-resolution photograph of the frontal zone allows us to understand why a historically stable glacier has entered a phase of accelerated changes. To learn more about its evolution, you can also consult This link about the Perito Moreno Glacier.
Among the findings, the identification of a underwater ridge on which the front rests. This natural barrier would have been key to its previous stability, by slowing the breakup of large blocks and limiting the floating of ice in deep waters.
Figures of the recent decline
Between 2000 and 2019, Perito Moreno barely retreated about 100 meters, an exceptional performance compared to other Patagonian glaciers. However, since 2019, records show a substantial increase from the withdrawal.
The research documents a recoil of up to 800 meters on the northwest shore of Iceberg Channel in just four years. Although the glacier still retains its basal support, the authors warn that the process could speed up if the front loses that anchor.
El thinning of the ice at the terminal end multiplied by more than sixteen, 0,34 meters/year (2000–2019) at an average of 5,5 meters/year since 2019. This transition signals a regime change that, due to its dynamics, may be difficult to reverseTo better understand how mass loss affects the glacier, we recommend consulting How glaciers respond to climate change.
Sources from the team—including the glaciologist Lucas Ruiz (IANIGLA)— they emphasize that this is not an immediate instability, but rather a scenario in which the risk of frontal collapse grows as thinning progresses and the flotation threshold approaches.
The underwater ridge and the risk of unanchoring
The data reveal that the Perito Moreno front is currently supported by a submerged crest. If the pace of thinning If the ice is maintained, the ice could break away from that ridge. The loss of contact with the seabed would increase the buoyancy, facilitating more iceberg calving and a much faster retreat.
This pattern has already been observed in nearby glaciers such as Uppsala y Viedma, who retreated several kilometers until reaching a new position of equilibriumThe authors estimate that it could follow a similar trajectory if the undocking from the front.
The climatic context reinforces this trend: measurements in the vicinity of the glacier show a warming of 0,2°C per decade since the mid-90s, with more marked increases in summer and spring. Less snow accumulation and more intense melting contribute to the loss of mass.
Glaciers that terminate in bodies of water often respond in a abrupt to these forcings, since the greater depth upstream of the front amplifies the instability. Hence the recommendation to maintain a continuous monitoring and refine models to anticipate possible scenarios. For more information on the status of other glaciers in Argentina, see glaciers in Argentina.
Its scientific value, as well as its scenic and tourist value, could be affected by an accelerated decline, which will modify the accessibility in front and the dynamics of navigation by presence of icebergsThese extremes could occur if the process intensifies, making the change even more evident on the regional stage.
The Perito Moreno, which in the past was an example of stability In Patagonia, the region is currently undergoing a difficult period. The most recent data confirms a rythm change in its frontal evolution and thickness. Without definitive deadlines as to when an unanchoring could occur, researchers agree on the need to continue monitoring their behavior, since the loss of support under its forehead increases the probability of a rapid retreat without warning.
