In results published October 29, 2026, CryoPyr ranked the 2025–2026 campaign as the third-largest annual ice-loss year in its record, which began in 2012. The losses came despite record spring snow accumulation, and the reported measurements cover Aneto, Monte Perdido and Ossoue. CryoPyr’s monitoring summary
The 2025–2026 measurements
| Glacier | Mean thickness loss |
| Aneto | 2.4 m |
| Monte Perdido | 2.3 m |
| Ossoue | 3.1 m |
Mean thickness loss reported by CryoPyr for the 2025–2026 monitoring year.
CryoPyr also reported new fragmentation at Aneto and newly exposed bedrock at Monte Perdido. The lower western part of Monte Perdido’s glacier was evolving toward a small residual ice patch. Ossoue showed no apparent movement. Debris accumulation and surface darkening were widespread across the monitored glaciers.
What the 2034 projection says about each glacier
A separate peer-reviewed study published in 2025 modeled the three largest Pyrenean glaciers under three climate scenarios. By 2034, it projects little or no remaining ice at Monte Perdido and Ossoue. Aneto is projected to break into patches totaling less than 2 hectares, with no single patch larger than 1 hectare. The 2025 study in Annals of Glaciology
The scenarios were RCP4.5, “committed ice loss” based on the 2010–2020 climate, and a repeat of the extreme conditions of 2022. The Instructed Glacier Model (IGM) simulated ice thickness, area and movement using ice-mass conservation, surface mass balance and ice-flow physics. The 2034 result is a model projection under those scenarios, rather than a fixed date for the disappearance of every ice remnant.
How the study reconstructed the glaciers’ starting conditions
The 2025 study combined 11.4 kilometers of ground-penetrating-radar profiles collected in different years with records of elevation change. It used surveys by unmanned aerial vehicles in September and October 2024 to update its reconstructions. Radar measurements between surveyed points were extended with radial-basis-function interpolation, a method for estimating values between known observations.
For the study’s end-of-2024 reconstruction, average ice thickness was estimated at 11.6 m for Aneto, 15.0 m for Monte Perdido and 15.1 m for Ossoue. The study also reports that the glaciers thinned by 16.4 m, 15.8 m and 21 m, respectively, from 2011 to 2024.
The reconstruction’s reported uncertainties varied by glacier and method: the mean thickness error in cross-validation was ±1.2 m for Ossoue; residual uncertainty reached ±5 m in water-rich sectors of Monte Perdido; and interpolation uncertainty was ±0.3 m for Aneto. These figures describe the study’s reconstructed starting ice conditions.
What an earlier study found at Monte Perdido
A separate study of Monte Perdido from 1981 to 2014 found that thinning accelerated after 1999, then slowed during 2011–2014, a period that included two unusually wet winters and cool summers. Its authors said local temperature and precipitation trends did not seem sufficient to explain the acceleration over that study period. They considered a mismatch between the glacier and the climate, along with energy-balance feedbacks, plausible explanations. The historical Monte Perdido study
