18-07-2025
1.5m-year-old ice core to reveal how humans almost died out
A n ice core drilled from deep beneath the frozen deserts of Antarctica is likely to be more than 1.5 million years old, with scientists set to unlock the climate secrets hidden inside.
It is the oldest ice on Earth, dug out over four Antarctic summers in a glass-like cylinder that is 2.8km long. Some of its segments have now arrived in the UK where researchers at the British Antarctic Survey in Cambridge will try to access the trove of information trapped inside.
Suspended within the ice are air bubbles. Each acts like a tiny time capsule, having captured a tiny portion of the Earth's atmosphere as it was when the ice first formed.
They could contain clues about a period between 900,000 and 1.2 million years ago known as the Mid-Pleistocene Transition when our ancestors may have been pushed to the brink of extinction by a period of extreme cooling, with populations plummeting from 100,000 to just 1,000 individuals.
They want to understand why the gap between ice ages lengthened from 41,000 to 100,000 years at around this time.
'It's an amazing achievement,' Professor Carlo Barbante from Ca' Foscari University of Venice told the BBC.
'You have in your hands a piece of ice that is a million years old. Sometimes you see ash layers coming from volcanic eruptions. You see the tiny bubbles inside, some bubbles of air that our ancestors breathed a million years ago.'
An ice core drilled from deep beneath the frozen deserts of Antarctica is being cut into one-metre sections to be shipped to scientific institutions around Europe
PNRA/IPEV
The air and particles trapped in the ice will tell scientists about the composition and temperature of the atmosphere dating back more than a million years. Analysis of previous ice cores helped scientists reach the conclusion that the current rise in global temperatures is being caused by human activity, specifically the burning of fossil fuels.
The new ice core is likely to contain ice that is 400,000 years older than a famous core called Epica.
The site from which the ice core was drilled is called Little Dome C, at an elevation of around 3,000m on the east of the continent, where workers had to operate at temperatures as low as -35C.
The core, nine times the length of the Shard skyscraper in London, is being cut into one-metre sections to be shipped at -50C to institutions around Europe.
The team of researchers worked in temperatures as low as -35C
PNRA/IPEV
'What they will find is anybody's guess but it will undoubtedly enlarge our window on our planet's past,' said Professor Joeri Rogelj from Imperial College London, who is not part of the research.
The project to extract the ice began in 2021. Researchers will test their analytical tools and methods on the younger ice that was closer to the surface. Barbante said at the time: 'With many new PhD students coming online, and new groups getting involved, and new analytical techniques always being developed, we will make good use of the ice younger than 800,000 years.
'We will also use the younger ice to ensure our techniques are working well by the time we get to the deep ice, where we only get one chance to get all the analyses right.'
