In a Brussels laboratory, scientists study ice for climate clues.
In a small, air-conditioned room at a Brussels university, scientists wearing heavy coats are cutting through Antarctic ice cores tens of thousands of years old, searching for clues about our planet's climate.
Trapped within the ice tubes are tiny air bubbles, capable of providing a glimpse into what the planet's atmosphere was like at that ancient time.
“We want to know more about past climates because we can use them as an analogy for what might happen in the future,” explains Harry Zekollari, a glaciologist at Vrije Universiteit Brussel (VUB).
Zekollari is part of a four-person team that traveled to Antarctica in November to find some of the world's oldest ice.
In Antarctica, it is possible to find ice millions of years old, kilometers deep.
But it is very difficult to reach these layers, and expeditions to drill through the ice are costly.
A recent EU-funded mission that returned samples dating back 1.2 million years cost a total of around 11 million euros (72 million reais).
To reduce costs, the team from VUB and the Free University of Brussels (ULB) used satellite data and other clues to pinpoint areas where ancient ice might be most accessible.
Like the water it is made of, ice flows towards the coast, albeit more slowly, explains Maaike Izeboud, a remote sensing specialist at VUB.
When the flow hits an obstacle, such as a mountain, the lower layers can be pushed up, closer to the surface.
In some extremely unusual places, weather conditions, such as strong winds, prevent a snowpack from forming, leaving thick layers of ice exposed.
Named for its color, which contrasts with the whiteness of the rest of the continent, blue ice represents only about 1% of Antarctica's territory.
“The blue ice areas are very special,” Izeboud emphasizes.
His team focused on a patch of blue ice 2,300 meters above sea level, about 60 kilometers from the Belgian Antarctic research station Princess Elisabeth.
Some ancient meteorites had previously been found there, an indication that the surrounding ice is also very old, the researchers explained.
So a container camp was established, and after a few weeks of measuring and drilling, in January the team returned with 15 ice cores totaling about 60 meters in length.
They were later sent from South Africa to Belgium, where they arrived at the end of June.
Inside a sturdy cement building in the Belgian capital, these ice cylinders are now being cut into smaller pieces and then sent to specialized laboratories in France and China for dating.
Zekollari hopes to confirm that some of the samples, taken from a shallow depth – around 10 meters – are around 100,000 years old.
This would allow them to go back and dig a few hundred meters deeper in the same place.
“It’s like a treasure hunt,” says Zekollari, 36, who looks a bit like the Indiana Jones of climate research.
"We're trying to mark the right spot on the map (...) and in a year and a half, we'll come back and drill at that spot," he said. "We're dreaming a bit, but we hope to get ice that's three, four, five million years old."
Ice from this ancient time could provide valuable information for climatologists studying the effects of global warming.
Climate projections and models are calibrated using existing data on past temperatures and greenhouse gases in the atmosphere, but there are still some missing pieces of the puzzle.
By the end of the century, temperatures could reach levels similar to those the planet last experienced between 2.6 and 3.3 million years ago, says Etienne Legrain, a 29-year-old paleoclimatologist at the ULB.
But there is currently little data on CO2 levels at that time, a crucial piece of information for understanding how much more warming we can expect.
“We don’t know the relationship between CO2 concentration and temperature in a warmer climate than the current one,” Legrain highlights.
His team hopes to find it trapped within the ancient ice. "The air bubbles are the atmosphere of the past," he says. "It really is like magic."
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