BBC – Future – The ancient memories trapped in the world's glaciers



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

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

Burgay, a glaciologist at the Ca 'Foscari University of Venice in Italy, camped at the iconic peak that separates 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 the ice cores of the Col du Dome glacier, which then flew downhill and were stored in the Grenoble laboratory. The researchers hope that some day, part of these ice cores will travel to Antarctica, where a vault made of custom-made snow will preserve the knowledge it contains over the next centuries.

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After this first mission, the team challenged the Illimani mountain in Bolivia, this time reaching a glacier on the side of a peak of 6,300 m (20,669 ft), and collecting cores that had to be lowered on foot, since there were no helicopters available. Kilimanjaro in Tanzania is next on the list, with an expedition planned for this year, and more glaciers in danger of extinction will follow as new international partners join the Italian-French initiative.

Research shows that the world's glaciers have been shrinking dramatically 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 could lose most of the planet's ice cover by the end of the century, with the exception of the Greenland ice sheets and the Antarctica.

"The world's glaciers are literally disappearing from our feet," says Carlo Barbante, a paleoclimatologist also at the 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, it is a disastrous situation. But the ice in the glacier area is also a lot of information.

The 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 the lack of water in vulnerable areas such as the Subindian continent," says Barbante. "But like the scientists who study ice as a file, we realize that we are also losing vitality … We felt we had to do something about it."

Together with the 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 extends thousands of years into the past. Trapped in the ice are small gas bubbles, dust particles, pollen and even small organisms that can provide a vital window to events that occurred before human records began.

Currently, the ice cores are extracted one meter at a time, drilling the surface of the glacier, making a first visual badysis of the core before preparing them for shipping in containers that usually have a width of 10 cm (4 inches). This process is repeated hundreds of times as researchers deepen more and more to capture older ice sheets, sometimes reaching extreme depths of 900 m (2,953 ft). As researchers dig deeper, each meter of ice has been compressed further by the weight of the layers above, which means they store chemicals and other particles accumulated over a longer period.

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

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

"Ice also works like a paleothermometer," says Burgay. "It records ambient temperatures where a certain snow cover fell at any time."

With 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 6,000-year-old traces of iron in ice from a core mined in Greenland. The tiny levels of metal can provide clues about the ancient volcanic activity that threw metallic dust into the atmosphere.

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

"One can argue that the 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 whether within 200 years someone will be able to pay the electricity bill." History shows how conflicts, changing research priorities and natural disasters make it difficult to predict the future of any long-term scientific effort, he says.

It has led scientists to look for 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. region destined for peaceful scientific endeavors. "

The creation of a sanctuary for the disappearing ice of today could also offer benefits that are now unimaginable.

Signed in 1959 and entered into force in 1961, the Antarctic Treaty brings together 53 countries active in the region, stipulating that the territory "shall be used only for peaceful purposes" and that scientific observations and Antarctic results shall be exchanged and placed available to the public. .

As long as the treaty is maintained, says Bess Koffmann, a geologist at the University of Maine in the United States, Antarctica will remain a safe place. But the treaty is ready for renegotiation in 30 years. (Read more about how archaeological discoveries could shape the future of the continent).

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

Creating a sanctuary for the ice that disappears today could also offer benefits that are now unimaginable. As new tools and technologies become available, it could allow scientists to open new windows to our planet's past, and perhaps even study ancient viruses and bacteria preserved in the ice.

"Technologies have evolved rapidly in recent decades, and now we are making measurements that we did not even dream of 30 or 40 years ago," says Koffmann.

We are losing our glaciers very quickly, and without archiving the information they contain, we simply are not giving ourselves the opportunity 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 badyze the nuclei without even touching them".

But to get to this point it is essential to build a repository 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 simply are not giving ourselves the opportunity to understand the changes that may occur in the future."

Scientists often 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 can see the changes on a much smaller scale." This means creating a detailed picture of local climates that would be lost by badyzing only polar ice.

The Ice Memory team expects to have a wide range of samples ready to be stored in Antarctica by 2020, in a custom-made vault built near the Franco-Italian research station Concordia. The researchers plan to use a method that has been successfully tested in Greenland, which consists of 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 previously removed to recreate the trench in the structure, and we wait for it to harden for a few days," explains Barbante. At that time, the balloon deflates and can be easily removed. "In this way we create a natural structure that is low cost and has no environmental impact."

Barbante admits that after one or two decades, the structure is likely to give way under the weight of additional snow falling on it. "But nuclei can move 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 those from Russia, the United States and China, are already collecting additional material during their independent expeditions, so they can contribute to the project in the future.

According to current projections, no matter what we do now to curb global emissions, many of the world's glaciers have little hope of surviving beyond a few human generations, and some lose a third of their ice over the next century. . Soon, these few hundred meters of ice cores may be all that remains of many ancient ice languages.

The efforts of a few intrepid explorers who venture into the mountains to collect these cores are helping to ensure that the secrets they contain are available so that future generations can unlock them.

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