The largest glacier in Spain triples its losses due to heat waves

This week, a group of biologists and geographers has ascended the Aneto glacier, the largest in Spain, to study a kind of black mucus that is appearing on the surface of the ice. They are cryoconites, a microcosm of bacteria, archaea and dust, which is one more marker that the glacier is in its terminal state. These black spots accumulate heat and increase the melting of the ice, already severely punished after two years of record-breaking summer temperatures.

Just now, the most complete study that has been carried out on the evolution of this mass of ice, which is one of the most emblematic in the Pyrenees and receives thousands of visitors each year, has just been published. The work has used different methods to estimate the retreat of the glacier from 1981 to the present. The results read like an obituary. The glacier continues a trend of increasingly accelerated disappearance and the latest heat waves have tripled its retreat. Only in 2022 did the ice lose three meters in thickness on average, like a floor with high ceilings. It is the highest figure ever recorded and coincided with a year of record temperatures throughout Spain.

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Logic seemed to indicate that the disappearance of the Pyrenean glaciers should be stopped. There is less and less ice to melt and this accumulates in the highest and shady areas. But the new study shows that the Aneto merger is increasingly accelerated. Since 1981 the thickness of the ice has lost 30 meters, the equivalent of a ten-story block. The total extension has been reduced to less than half, 64%. In 1850, when the planet’s temperatures began to rise continuously, there were 52 glaciers in this mountain range. In 2020 there were 21 left and almost 90% of its entire surface has been lost.

He has ten years left

Nacho López-Moreno, a researcher at the Pyrenean Institute of Ecology and a veteran student of these glaciers, summarizes the consequences of the work, published by the European Geosciences Union. The work warns that the state of the Aneto glacier is “terminal”. “In recent years, the glacier had been losing a meter and a half in thickness per year. Taking into account that on average there is a thickness of about 11 meters, in about 10 years the Aneto will no longer be a glacier. But if we also have summers like 2022, it will hold much less ”, he sums up.

López-Moreno’s team has spent years studying the last perpetual ice in Spain with an unprecedented level of detail, and with unique personal dedication. As soon as they climb down a wall to recover a snow-crushed weather station, as they climb steep slopes or set up makeshift camps to spend the night in the dead of winter. For this latest study, the team deployed a georadar, a kind of technological snake that was pulled by five people and dragged back and forth across the glacier. They were two days of work and more than seven kilometers walked through the ice. To these data have been added the high-resolution photos taken with a drone since 2020 and the use of aerial photographs taken by the National Geographic Institute. “The GPR sends out a signal that crosses the ice, bounces off, and depending on how long it takes to return, we know its exact thickness at each point,” explains Eñaut Izaguirre, a geographer at the University of the Basque Country. These data were “vital” to be able to compare with the relief models from 1981 to 2022, he adds.

“With the thaw these mountains are becoming more dangerous”

Eñaut Izaguirre, University of the Basque Country

The Aneto has his death announced. There is hardly any surface left to accumulate snow in winter. It has been divided into two areas and it is imminent that the largest part will be fragmented into three other sectors, which will accelerate its disappearance. The ice will stop flowing down the slope —an essential feature of a glacier— until there is only one immobile glacier left just below the Maldito, the neighboring peak of Aneto. “With the thaw these mountains are becoming more dangerous,” explains Izaguirre. The ice in the cracks in the rocks melts and more and more blocks fall. The landslides are greater in the height of summer, when the glacier receives more visitors. And the debris ends up lining the ice and acting as radiators that accelerate melting. It is something very similar to what happens in the Alps, and in most mountain ranges in the world, but in Spain the glaciers are much closer to the end.

Video: Eñaut Izaguirre

One of the most spectacular witnesses to the speed with which the last glaciers in Spain are disappearing is a lake with turquoise waters that formed in 2015; the Unnamed. At 3,150 meters above sea level, it is the highest in the entire Pyrenees. It is one of the most appropriate places to understand how the landscape and the organisms that inhabit it will change as the ice disappears, forming lakes, Pyrenean lakes. Ixeia Vidaller, an IPE researcher, explains that the team has calculated what the Aneto landscape will be like when there is no ice left. “In the deepest areas, another two or three lakes will probably form, which will add to the Innominato. Although so many rocks detached from the walls can fall that could fill those deposits ”, she points out.

The high temperatures recorded in 2022 have also wreaked havoc on the other great Pyrenean glacier, Monte Perdido, where ever larger blocks are breaking off, filling the mountain with their roar. In 2022, this glacier lost almost four meters in average thickness, an absolute record, explains Jesús Revuelto, an IPE researcher. “In the most favorable years, the glaciers of the Pyrenees remain, but when bad years arrive, the losses completely unbalance it. The glaciers are being confined to the most precise, coldest and shady areas, but despite this they continue to melt at an accelerated rate”, he details.

It is possible that this year will be almost as bad as the last. Despite the fact that the temperatures have not been as high, there are still two melting months ahead until the first snows of autumn. If there are a few more summers like this, it is likely that the glaciers will disappear this decade.

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