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



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Speaking of a cacophony of humming machines in a crowded Swiss laboratory, François Burgay speaks of the open, calm sky over Mont Blanc. "At 4,200 meters above sea level, you never expect such a brilliant night," he says. This is the lack of light pollution from the Earth that gives the sky its unique milky quality.

"I think I can speak on behalf of many of my peers when I say that to do this work, you have to be an explorer of hearts," he smiles.

Burgay, a glaciologist from the University of Ca 'Foscari in Venice, Italy, camped for a week at the iconic summit separating France from Italy in August 2016, the first field mission of his career . As part of the Ice Memory project, he was there to collect ice cores on the Col du Dome glacier, which were then stolen and stored in the Grenoble laboratory. The researchers hope that someday, some of these ice cores will travel to Antarctica, where a custom-built snow vault will preserve the knowledge it will hold for centuries to come.

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As a result of this first mission, the team braved Mount Illimani in Bolivia, this time reaching a glacier on a summit at 6,300 m, collecting carrots that had to be dismounted, lack of helicopters. . Kilimanjaro, Tanzania, is next on the list. An expedition is planned for later this year. Other endangered glaciers will follow, new international partners joining the Franco-Italian initiative.

Research shows that glaciers around the world have been shrinking considerably for some time, probably due to man-made climate change. The UN's Intergovernmental Panel on Climate Change estimates that if global warming continues, we could lose most of the world's ice cover by the end of the century. exception of the Greenland and Antarctic ice sheets.

"The world's glaciers are literally disappearing from our feet," said Carlo Barbante, a paleoclimatologist also at Ca 'Foscari University and one of the founders of the Ice Memory project. For the 1.5 billion people who depend on glaciers for drinking water and irrigation, the situation is dire. But ice in the glacier region is also a mine of information.

Glaciers of the world are literally disappearing from our feet – Carlo Barbante

"We often focus on the immediate threats caused by melting ice, such as lack of water in vulnerable areas like the sub-Indian continent," Barbante said. "But as scientists who study ice as an archive, we realize that we are also losing information, we felt we had to do something about it."

Barbante and his French climatologists and glaciologists undertook to recover ice samples from glaciers around the world. Each ice core represents a valuable archive of history that extends over thousands of years. Bubbles of gas, dust particles, pollen and even tiny organisms trapped in the ice can provide a vital window on what happened before the start of the human archive.

Currently, the ice cores are extracted one meter at a time, drilling the surface of the glacier and performing a first visual analysis of the carrot before being prepared for shipping in containers of a width usual 10 cm (4 in). 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 feet). As researchers dig deeper, each meter of ice has been further compressed by the weight of the layers above, which means that they store chemicals and other accumulated particles for a longer period of time. long.

Once in the laboratory, the carrots are then cleaned and the samples melt slowly in a controlled environment. Glaciologists can thus analyze water to identify metals or gases such as carbon dioxide.

Each ice core represents a valuable archive of history that extends over thousands of years in the past

"The ice is also a paleothermometer," says Burgay. "It records the temperatures of the environment where a certain layer of snow fell at all times."

With the help of this information, researchers can reconstruct the Earth's changing climate over millennia, providing valuable information that can be used by scientists to model climate change. Burgay's laboratory machines, for example, are currently searching for traces of iron in 6,000-year-old ice from a nucleus extracted from Greenland. The low levels of metal can provide clues to the ancient volcanic activity that has spread metal dust into the atmosphere.

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

"One could argue that ice cubes would be safe in a commercial refrigerator in Venice or Paris," Barbante said. "But we do not think in the short term.We can not predict if in 200 years, someone will still be able to pay the electricity bill." History shows how conflict, changing research priorities and natural disasters make it difficult to predict the future of any scientific activity in the long term, he said.

This has led scientists to seek a more permanent solution.

"The Antarctic is the safest place to store the samples," says Barbante. "First of all, because it's a natural refrigerator, with average annual temperatures hovering around -50 ° C, and because it's not owned by any country." is the only region for peaceful scientific activities ".

Creating an ice sanctuary that disappears today could also bring unimaginable benefits today.

Signed in 1959 and entered into force in 1961, the Antarctic Treaty brings together 53 active countries in the region. It states that the territory "shall be used only for peaceful purposes" and that "the scientific observations and results of Antarctica shall be exchanged and made available free of charge. & Nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;

According to Bess Koffmann, a geologist at the University of Maine in the United States, Antarctica will remain a safe place as long as the treaty remains in effect. But the treaty must be renegotiated in 30 years. (Learn more about how archaeological discoveries could shape the future of the continent).

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

The creation of a sanctuary for endangered ice could also offer unimaginable benefits today. As new tools and technologies become available, this could allow scientists to discover new windows about our planet's past and perhaps even study old viruses and bacteria stored in the ice.

"Technologies have evolved rapidly over the last few decades and we are now taking measurements that we did not even dream about 30 or 40 years ago," Koffmann says.

We are losing our glaciers very quickly and without archiving the information they contain, we just do not get the chance to understand the changes that may occur in the future – Emma Smith

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

But to get to this point, it is essential to build a repository as long as we can, says Emma Smith, a 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 getting the chance to understand the changes that may occur in the future."

Scientists often focus on polar ice because it is there that they can discover the oldest recordings, Smith explains. "But if you look at the regional ice cores from smaller glaciers, you can see much smaller changes." This means creating a detailed picture of local climates that would be missed by analyzing only the polar ice.

The Ice Memory team hopes to have a wide range of samples ready to be stored in Antarctica by 2020, in a custom-built safe near the Franco-Italian Concordia research station. The researchers plan to use a proven method in Greenland of digging a trench and inserting an inflatable balloon that will serve as a mold for the cave.

"We then blew the snow that we had previously removed to create the trench on the structure and wait for it to harden for a few days," Barbante says. At this point, the balloon is deflated and can be easily removed. "In this way, we create a natural structure with low cost and no impact on the environment."

Barbante admits that after one or two decades, the structure will probably sag under the weight of the snow falling on it. "But the nuclei can be moved relatively easily to a new structure built in the same way," he adds.

The project has already received support from UNESCO and Barbante says that a growing number of teams, including Russian, American and Chinese teams, are already collecting additional material during their independent expeditions. They will be able to contribute to the project in the future. future.

According to current projections, no matter what we are currently doing to reduce global emissions, many glaciers around the world have little hope of surviving beyond a few human generations, some losing a third of their ice next century. Soon, these few hundred meters of ice cores may be all that remains of many ancient ice tongues.

The efforts of some intrepid explorers who have ventured into the mountains to collect these nuclei help to ensure that future generations can discover the secrets they contain.

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