BBC – Future – The ancient memories caught in the glaciers of the world


Speaking of a cacophony of buzzing machines in a Swiss laboratory, François Burgay talks about the calm and open sky above Mont Blanc. "At 4,200 meters above sea level, you would never expect the night to be so bright," he says. It is the lack of light pollution of the Earth that gives the sky its unique and milky quality.

"I think I can speak for many of my colleagues when I say that to do this job you have to be a heart explorer," he smiles.

Burgay, a glaciologist at Ca 'Foscari University in Venice, Italy, camped on the iconic peak separating France and Italy for a week in August 2016, the first field mission of his career. As part of the Ice Memory project, he was there to collect ice samples from the Col du Dome glacier, which were then taken down and stored in the laboratory in Grenoble. One day, researchers hope, part of these ice cores will travel all the way to Antarctica, where a vault built under the snow will preserve the knowledge it contains centuries later.

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After this first mission, the team faced the Illimani mountain in Bolivia, this time reaching a glacier next to a 6,300 meter high peak and collecting cores that had to be transported on foot since the helicopters were not available. . Kilimanjaro in Tanzania is next on the list, with a planned expedition towards the end of this year, and more threatened glaciers will follow as new international partners join the Franco-Italian initiative.

Research shows that the world's glaciers have dwindled drastically for some time, probably due to human-induced climate change. The UN Intergovernmental Panel on Climate Change estimates that if global warming continues unabated, we may lose most of the planet's ice cover by the end of the century, with the exception of the Greenland and Antarctic glaciers.

"The world's glaciers are literally disappearing under our feet," says Carlo Barbante, a paleoclimatologist at Caos Foscari University and one of the founders of the Ice Memory project. For the 1.5 billion people who rely on glaciers for drinking water and irrigation, this is a disastrous situation. But the ice in the glacier area also a wealth of information.

The glaciers of the world are literally disappearing under our feet – Carlo Barbante

"We often focus on the immediate threats brought about by the melting of the ice, such as the lack of water in vulnerable areas such as the sub-Indian continent, but as scientists studying ice as a file, we realize that we are also losing vital space" . We felt we had to do something about it. "

Together with French climatologists and glaciologists, Barbante and his team set out to rescue ice samples from the world's glaciers. Each ice core represents a precious archive of history that spans thousands of years into the past. Stuck on ice are tiny gas bubbles, dust particles, pollen, and even tiny organisms that can provide a vital window to events that happened before the beginning of human records.

Currently, the ice cores are drawn one meter at a time, drilling the surface of the glacier, performing a first visual analysis of the core before being prepared for transport in containers that are generally 10cm wide. This process is repeated hundreds of times as researchers drill deeper and deeper to capture older layers of ice, sometimes reaching extreme depths of 900 m (2,953 ft). As researchers deepen, each meter of ice has been compressed more by the weight of the layers above, which means they store chemicals and other particles accumulated over a long period.

Once in the laboratory, the cores are cleaned and the samples are melted slowly in a controlled environment so glaciologists can analyze the water to identify metals or gases, such as carbon dioxide.

Each ice core represents a precious archive of history that spans thousands of years into the past

"Ice also doubles as a paleothermometer," says Burgay. "It records the ambient temperatures in which some snow cover fell at any time."

Using this information, researchers can reconstruct the evolution of Earth's climate over millennia, providing valuable information that scientists can use to model climate change. Machines in the Burgay laboratory, for example, are currently looking for traces of 6,000-year-old ice iron extracted from a Greenland nucleus. Minimal levels of metal can provide clues about ancient volcanic activity that has spewed metallic dust into the atmosphere.

After cleaning, the remaining cores are prepared for long-term storage in the repository.

"It could be argued that ice cores would be safe in a commercial refrigerator in Venice or Paris," says Barbante. "But we are not thinking in the short term. We can not predict if 200 years from now someone can still pay the electricity bill." History shows how conflict, changing research priorities and natural disasters make it difficult to predict the future of any long-term scientific endeavor, he says.

This has led scientists to seek a more permanent solution.

"Antarctica is the safest place to store samples," says Barbante, "First, because it is a natural refrigerator, with average annual temperatures around -50 ° C, and also because it does not belong to any country. for peaceful scientific endeavors. "

Creating an ice sanctuary that is disappearing today may also offer benefits unimaginable nowadays

Signed in 1959 and entered into force in 1961, the Antarctic Treaty brings together 53 countries active in the region, stipulating that the territory "will be used only for peaceful purposes" and that "scientific observations and results from Antarctica will be exchanged and made available for free." & # 39;

As long as the treaty remains, says Bess Koffmann, a geologist at the University of Maine in the US, Antarctica will remain a safe haven. But the treaty is ready for renegotiation 30 years from now. (Read more about how archaeological discoveries can shape the future of the continent.)

"There is always a risk that a country will refuse to sign the agreement to take advantage of the region's unexplored resources, such as coal and other minerals," warns Koffmann.

Creating an ice sanctuary that is fading today may also offer benefits unimaginable nowadays. As new tools and technologies become available, this may allow scientists to unlock new windows in the past of our planet and perhaps even study old viruses and bacteria preserved in the ice.

"Technologies have evolved rapidly in the last few decades, and now we are making measurements that we had not even dreamed in 30 or 40 years," says Koffmann.

We are losing our glaciers very quickly, and without archiving the information they contain, we are simply not giving ourselves a chance to understand the changes that may happen in the future – Emma Smith

One day, says Barbante, the imaging techniques will be so advanced that "we can analyze the nuclei without touching them."

But to get to that point, it is essential to build repositories while we can, says Emma Smith, glaciologist and geophysicist at the Alfred Wegener Institute in Bremerhaven, Germany. "We are losing our glaciers very quickly, and without archiving the information they contain, we are simply not giving ourselves the chance to understand the changes that may occur in the future."

Scientists generally focus on polar ice because that's where they can discover the oldest records, says Smith. "But if you look at the regional ice cores of smaller glaciers, you may notice changes on a much smaller scale." That means creating a detailed picture of local climates that would be lost by analyzing the polar ice alone.

The Ice Memory team expects to have a large variety of ready-to-stock samples in Antarctica by 2020 in a tailor-made safe built near the French-Italian research station Concordia. The researchers plan to employ a method that has been successfully tested in Greenland, which involves digging a trench and inserting an inflatable balloon that will be used as a mold for the cave.

"Then we blow the snow that we removed earlier to create the trench back in the structure and we expect it to harden for a few days," explains Barbante. At that point, the balloon is emptied and can be easily removed. "In this way, we created a natural structure of low cost and without environmental impact".

Barbante admits that after a decade or two the structure will likely diminish under the weight of more snow falling on it. "But the cores can be moved relatively easily into a new structure built in the same way," he adds.

The project has already won support from Unesco, and Barbante says a growing number of teams, including Russians, Americans and Chinese, are already collecting extra material during their independent expeditions to contribute to the project. future.

According to current projections, no matter what we do now to reduce global emissions, many of the world's glaciers have little hope of surviving beyond a few human generations, with some losing a third of their ice in the next century. Soon, those few hundred meters of ice cores may be all that remains of many ancient ice tongues.

The efforts of some intrepid explorers who venture into the mountains to collect these cores are helping to ensure that the secrets they contain are available for future generations to unlock.

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