5 days ago
Scientists hunt ancient ice for climate clues
UMBERTO BACCHI
In a small, refrigerated room at a Brussels university, parka-wearing scientists chop up Antarctic ice cores tens of thousands of years old in search of clues to our planet's changing climate.
Trapped inside the cylindrical icicles are tiny air bubbles that can provide a snapshot of what the earth's atmosphere looked like back then. "We want to know a lot about the climates of the past because we can use it as an analogy for what can happen in the future", said Harry Zekollari, a glaciologist at Vrije Universiteit Brussel (VUB).
Zekollari was part of a team of four that headed to the white continent in November on a mission to find some of the world's oldest ice — without breaking the bank.
Ice dating back millions of years can be found deep inside Antarctica, close to the South Pole, buried under kilometres of fresher ice and snow. But that's hard to reach and expeditions to drill it out are expensive.
A recent EU-funded mission that brought back some 1.2-million-year-old samples came with a total price tag of around $12.8 million. To cut costs, the team from VUB and the nearby Universite Libre de Bruxelles (ULB) used satellite data and other clues to find areas where ancient ice might be more accessible.
Belgian scientists holds blue ice samples in a laboratory in Brussels. - AFP
BLUE ICE
Just like the water it is made of, ice flows towards the coast — albeit slowly, explained Maaike Izeboud, a remote sensing specialist at VUB. And when the flow hits an obstacle, say a ridge or mountain, bottom layers can be pushed up closer to the surface.
In a few rare spots, weather conditions like heavy winds prevent the formation of snow cover — leaving thick layers of ice exposed.
Named after their colouration, which contrasts with the whiteness of the rest of the continent, these account for only about one per cent of Antarctica territory.
"Blue ice areas are very special", said Izeboud. Her team zeroed in on a blue ice stretch lying about 2,300 metres above sea level, around 60 kilometres from Belgium's Princess Elisabeth Antarctica Research Station.
Some old meteorites had been previously found there — a hint that the surrounding ice is also old, the researchers explained.
A container camp was set up and after a few weeks of measurements, drilling and frozen meals, in January the team came back with 15 ice cores totalling about 60 metres in length.
These were then shipped from South Africa to Belgium, where they arrived in late June.
Inside a stocky cement ULB building in the Belgian capital, they are now being cut into smaller pieces to then be shipped to specialised labs in France and China for dating.
Zekollari said the team hopes some of the samples, which were taken at shallow depths of about 10 meters, will be confirmed to be about 100,000 years old.
A Belgian scientist handles blue ice samples in a laboratory in Brussels. - AFP
CLIMATE 'TREASURE HUNT'
This would allow them to go back and dig a few hundred metres deeper in the same spot for the big prize. "It's like a treasure hunt", Zekollari, 36, said, comparing their work to drawing a map for "Indiana Jones".
"We're trying to cross the good spot on the map... and in one and a half years, we'll go back and we'll drill there", he said.
"We're dreaming a bit, but we hope to get maybe three, four, five-million-year-old ice".
Such ice could provide crucial input to 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 the puzzle has some missing pieces. — AFP
