January 26, 2021

Monte Perdido: Death of the last glacier in Spain | Science

Monte Perdido: Death of the last glacier in Spain | Science

Near the summit of Vignemale, one of the highest in the Pyrenees, there are some enigmatic gaps in the rock open with dynamite. They are the door to a time so different from the current one that its history seems a lie. In 1882 Count Henry Russell had rented the whole mountain for the symbolic price of one franc a year. He ordered the construction of seven caves from which he contemplated the sunset on the Ossoue Glacier and gave parties for his friends more than 3,000 meters high. The shelters were opened more or less flush with ice to enter without difficulty, but anyone who tries today will have to climb a rock wall several meters. It is one of the most picturesque evidence of a global phenomenon: the retreat of high mountain glaciers.

From the Andes to the Alps, from the Himalayas to Antarctica, the vast majority of the Earth's glaciers melt at an unprecedented rate since there are records, a phenomenon related to climate change. The process is especially intense in the Pyrenees, where the problem is not so much the retreat of the ice, but its extinction. Thirty-three of the 52 glaciers that existed in 1850 have disappeared, most of them after 1980. From the top of Mount Perdido (3,335 meters) you can see the most recent corpse: a beautiful turquoise lake that was a small glacier until late 90's.

Ignacio López-Moreno is like a surgeon who dies the patient without being able to do anything to save him. Son of a computer scientist and a housewife, this Zaragoza geographer is the only one among seven brothers who is dedicated to science. Since 2011, its team from the Pyrenean Institute of Ecology (CSIC) has analyzed the Monte Perdido glacier, the largest in the Spanish Pyrenees with Maladeta, and without a doubt the best studied (the third largest Pyrenean glacier is the one in Ossue who fell in love with Russell). No other high Spanish mountain range already shelters glaciers. These are the last of Spain.

"These glaciers, the southernmost in Europe, are in very limited conditions and everything points to the fact that they will be the first to disappear," explains López-Moreno. Studying them is "very important to see how they behave in these final phases, to what extent it accelerates or can slow down, and is an example for many other mountains that in a few decades will face this situation", highlights the researcher minutes before jumping to a helicopter with other IPE scientists to carry out this year's campaign, which has been attended by EL PAÍS. It will take just a few minutes to complete an ascent of about seven hours on foot, inhuman with the hundreds of kilos of equipment and food that must be brought to the camp.

A glacier is a mass of ice that is maintained throughout the year and is in continuous movement. Monte Perdido, one kilometer long and 500 meters high, advances three centimeters a day, twice as fast during daylight hours than at night. In recent decades it has been separated into two parts without connection, the superior and the inferior.

In the 1950s, the upper area of ​​the glacier was almost flat, but now it has an increasingly steep slope that hinders the accumulation of snow, essential for the glacier does not pass the critical line in which it loses more volume by melting during spring and summer than what he earns in winter. In 2011, a limestone cliff emerged between the ice of the lower glacier. The stones are like a radiator that reaches 15 degrees in the sun and accelerate the melting of the ice. Another enemy is the dust of the Sahara, which arrives in large clouds blown by the wind and dyes the brown snow, which diminishes its reflectivity and increases the fusion. All this adds to the main enemy of the Pyrenean glaciers, the increase in temperature.

the glacier
loses on average
one meter per year

"The average temperature has gone up 1.5 degrees. For many people it may seem little, but when we talk about climate change on a planetary scale the increase has been 0.7 degrees, so the Pyrenees are warming at twice the speed of the whole planet, "says López-Moreno .

During annual follow-up campaigns, the best part of the day is night. The group of six scientists swirls around a folding table where dinner is held in a gas stove. On this year's menu: sautéed piparras chilli peppers and fried eggs with rashers. At about 2,700 meters they know even better than it sounds. But the work of these researchers is not a path of roses. Each year they have to go down rock walls to replace thermometers and weather stations crushed by snow, save strong slopes with equipment on their backs, camping in summer and spring, when they have reached 17 below zero and winds of 100 kilometers per hour that knocked down the walls of snow that had been raised to protect the tent. Most of them are experienced mountaineers and speleologists. Miguel Bartolomé, the man who cooks on the heights, is the IPE expert in frozen caves, where the recoil of the ice is also patent. The day after returning from Monte Perdido, thermal sensors were placed in a cave in the Escuaín fountain system. It took 13 hours to travel along with members of the Speleology Center of Aragon, in collaboration with the Aragonese Federation of Speleology and the National Park of Ordesa.

The most detailed measure of the retreat of the glacier is provided by the terrestrial laser scanner, a machine that sends more than one million points of light to the glacier and builds a topographic map with a centimeter resolution. "This is the world's most studied glacier with this technology", explains Esteban Alonso-González, the member of the team that is responsible for the scan every year. "We have an uninterrupted series since 2011, and with several campaigns also in spring to measure also the snow accumulation maximums," he explains. After 2017, which was the worst year of the series, there has been very little loss or gain, but the general trend is one of decline. The data shows that the glacier has lost an average of five meters in thickness, although there are points that are 14 meters less. In general Monte Perdido goes back one meter a year. This adds to the previous measures using other techniques, which show a global loss of about 50 meters between 1980 and 2010.

"If we assume that the last years continue to happen, in 20 or 30 years a large part will disappear completely. Only the area of ​​live ice, more protected and with more snow in the upper part, which could last a decade longer, will survive, "explains López-Moreno. It will be a slow agony, since it is estimated that in its last years the retreat of the ice will slow down.


The Monte Perdido glacier is located within the Ordesa y Monte Perdido National Park, in the Pyrenees, in the province of Huesca.

Click on the most to see its location.

The disappearance of the glacier will not be a tragedy at the environmental or hydrological level. It is estimated that the thickness of the ice is about 30 meters, which in total hoards about eight cubic hectometres, equivalent to a small reservoir. Microbes and other species that live on the ice will disappear, but others will appear in the resulting lakes, explains López-Moreno. Life will go on, although for the next generations the only way to see a glacier in Spain is in photos.

The world pollution recorded in a lake

Blas Valero (right) and Miguel Bartolomé in the Marboré lake.
Blas Valero (right) and Miguel Bartolomé in the Marboré lake.

Blas Valero navigates the corpse of a glacier that disappeared 14,000 years ago. Its merger gave rise to the Marboré lake, the highest in the Pyrenees, at 2,590 meters above sea level and also one of the most interesting to resolve important questions about the Monte Perdido glacier opposite. There have been two historical stages in which the temperatures were very similar to the current ones, one in Roman times and the other during Medieval Climatic Optimum between the X and XIV centuries. The records of high mountain temperatures are scarce. The IPE team only has height measurements since 2013, the Góriz refuge temperature record since 1981; and those of the Midi de Bigorre Observatory (France) at 2,877 meters, with data on precipitation and temperature since 1903. Valero's team tries to reconstruct the past climate thanks to the sediments at the bottom of the lake, where seven meters of successive layers allow us to go back 13,000 years ago. The preliminary dates of the geologist of the IPE Ana Moreno point out that the glacier existed 2000 years ago, in Roman times, with which the oldest ice of the glacier should be even older. Human activity is evident in the Marboré sediments, according to Valero. In the sediments "we see the amount of heavy metals, lead and mercury, which comes from local mining, and especially on a global scale. There is a huge peak of the first globalization of the northern hemisphere during the Roman era. That peak of Roman mining is observed throughout the Pyrenees in a large increase in the amount of lead through atmospheric transport reached here. Then it descends, increases a little during medieval times and then increases from the nineteenth century with the industrial revolution. Begins to decrease one from the 80, when they begin to use unleaded gasoline, but does not fall to the level prior to the Roman era. The impact of what we do appears in a place as pristine and as remote as this. "


Source link