Origin of the data

Objective

The aim of the following contents is to disseminate the recent evolution of the Glaciers of the Pyrenees, taking as a basis the inventories and cataloguing from 1982-1985, until the closing of the glaciological campaign of 2024 (Jordi Camins 1982-1985 and 2024), using comparative photography as a fundamental tool.

In the initial inventory 93 glaciers were recorded (50 glaciers and 43 ice fields), which by the end of the 2024 campaign had been reduced to 42 (14 glaciers, 26 ice fields and 2 residual glaciers). In the last four decades, 51 of them have become extinct.

The future of Pyrenean glacier ice is not optimistic; the three smallest active glaciers each occupy an area of no more than 1.5 ha. In 18 of the 26 surviving glaciers and 2 residual devices, their surface area is less than or equal to 1 ha. The situation is no better for the largest glaciers, the Ossoue and Eastern Maladeta glaciers (third and fourth largest), which have lost twice as much surface area over the course of this century as they have today. Ossoue, with a current surface area of 14.5 ha, has lost more than 35 ha. The Oriental de la Maladeta has decreased by 26 ha to a current area of 13.9 ha.

Under current climatic conditions, the extinction of the Pyrenean GAs should occur in the middle of this century. The fact that in a single generation, ours, the total extinction of the glaciers of a mountain range as important as the Pyrenees will occur in a single generation is of great scientific interest.

Background

The last glaciation of the Quaternary (Milankovitch Variations or Cycles) began around 80,000 years ago and ended, according to different scientific criteria, between 18 and 12,000 years ago, when we naturally find ourselves in a warm interglacial period (Holocene).

During the cold pulses of the last glaciation, the Pyrenean glaciers reached an enormous development, occupying the current valleys with the limit of their fronts between 800 and 1,000 m altitude on the southern slope (Spanish-Andorran) and 400 m on the northern slope (mostly French, with some exceptions). By way of example, on the southern slope, their tongues reached lengths of 27 km in the Querol and Noguera Ribagorzana glaciers, 35 and 36 km in the Gállego and Ésera, and up to 50 km in the Noguera Pallaresa. Their thicknesses generally ranged between 400 and 600 m, reaching 900 m on the Ésera glacier. On the northern slope, the longest was that of La Garona (Aran Valley), with 66 km and a thickness of 800 m, those of Ariège and Gave de Pau with 52 km and that of Gave d’Ossoue with 38 km (Jaume Bordonau-1992). In short, all of them reached dimensions comparable to those of the present-day Himalayan glaciers.

Within the warm interglacial period in which we have been living for 18-12 thousand years, there have been alternating periods of more or less cold weather. By way of summary, we can highlight the last two climatic extremes, with temperatures higher than today’s. The first occurred about 2.000 years ago, coinciding with the maximum development of the Roman Empire, and the last between the 10th and 14th centuries (Medieval Climate Optimum), in both cases the Pyrenean ice disappeared practically in its entirety. The recent cold period to be highlighted is known as the Little Ice Age (LIA), and its glacial maximum took place between the 16th and 19th centuries.

The 93 Pyrenean glaciers that are the subject of this inventory (Jordi Camins 1982-1985) covered an area of 2.388,7 ha during and at the end of the Little Ice Age (approximately 1850). At the end of the 2024 inventory, the Pyrenean ice extent was 130.7 ha.

In the last 175 years, from the end of the LIA to the present day, its surface area has been reduced by 94.5%. Currently only 5.5% of the area occupied by these glaciers in the Little Ice Age is still preserved.

In the middle of the 19th century and coinciding with the end of the LIA, naturalists, hikers, tourists and glaciologists began to use incipient photographic devices, which sometimes by chance and sometimes on purpose, show us the state of the glaciers at that time, images which will also help us to show and learn about their recent evolution.

Glossary

Glaciers are considered as the set of different types of snow and ice accumulations. The definitions of interest are shown below:

Glacier: Accumulation of ice, snow, rocks, sediments and often liquid water that moves downhill under the influence of its weight and gravity.

Icefield: An accumulation of glacial ice without movement or without the minimum size to be considered a glacier.

Snowpack: A relatively small accumulation of snow, which, protected by shade and the particular shape of the terrain that shelters it, is able to subsist in summer.

Glacial moraine: A moraine is an accumulation of sediment transported by a glacier, usually a heterogeneous mixture of boulders, cobbles and sand.

Bibliographical references

• Pyrenees, glaciers from the air. Inventory and cataloguing 2017 (2018) . Jordi Camins – Besa & Keops SL.
• The last 100 glaciers of southern Europe (2013). Jordi Camins – Besa & Keops SL.
• Vidaller, I., Moreno, A., González-Sampériz, P., Pla-Rabés, S., Medialdea, A., del Val, M., López-Moreno, Juan Ignacio, Valero-Garcés, B. (2024, June). The last deglaciation in the central Pyrenees: The 47 ka Plan d’Están paleolake record (Ésera valley). Catena. Elsevier BV. http://doi.org/10.1016/j.catena.2024.108059.