Possibly the world’s oldest ice sheet, formed 1.2m years ago, has been mined from deep in Antarctica.
Working in temperatures of 35C, the team of scientists removed a 2.8km long cycle, or core, of ice – taller than the eight Eiffel Towers end-to-end.
Suspended within the ice are ancient air bubbles that scientists hope will help solve an enduring mystery about our planet’s climate history.
European scientists worked in the Antarctic for four summers, competing with seven nations to be the first to reach the rock beneath the frozen continent.
Scientists excavate this ancient ice and store it in frozen caves on the ice [PNRA_IPEV]
Their work could help solve one of the biggest mysteries in our planet’s climate history – what happened 900,000-1.2 million years ago when the ice cycle was disrupted and some researchers say our ancestors came close to extinction.
“It’s an amazing achievement,” said Prof. Carlo Barbante of Ca’ Foscari University of Venice who coordinated the study.
“In your hands you have a million-year-old ice. Sometimes you see layers of ash from volcanic eruptions. You see small bubbles inside, bubbles of air that our ancestors breathed a million years ago,” he said. .
The team was led by the Italian Institute of Polar Sciences and included 10 European countries.
An international team worked for weeks in temperatures of -35C to excavate the ice [PNRA_IPEV]
It had to transport the drilling equipment, laboratories and camp 40km in snowmobiles from the nearest research site.
The excavation site, called Little Dome C, is on the Antarctic plateau in the east of the continent, about 3000m high.
Ice cores are important to scientists’ understanding of how the climate is changing.
They capture air bubbles and particles that reveal levels of greenhouse gas emissions and temperature variations that help scientists chart how climates have changed over time.
Data from other ice cores, including one called Epica, helped scientists conclude that the current increase in temperature related to greenhouse gas emissions is caused by people burning fossil fuels.
The ice core is cut into 1m pieces and will eventually be divided between scientific institutions for analysis [PNRA_IPEV]
But scientists wanted to go back in time.
Now with this project Beyond Epica: Oldest Ice they have discovered another 400,000 years of history.
“There is a lot of the past in the future. We look at the past to better understand how the climate works and how it can manifest in the future,” said Prof. Barbante.
The team has had a “crushing last few days” as they have been able to drill deeper than expected from the radar data, said Dr Robert Mulvaney, ice core scientist at the British Antarctic Survey.
The drilling took place 40 kilometers from the Italian-French Concordia research station [BBC]
The core was slowly pulled from the ice sheet using a drill and the scientists carefully cleaned the ice using cloths.
It is now cut into one meter pieces to be transported at -50C from Antarctica by boat.
These pieces will eventually reach the freezers of several European institutions, including the British Antarctic Survey in Cambridge, where scientists will begin their analysis.
Experts want to understand what happened during a period of 900,000 to 1.2 million years ago called the Mid-Pleistocene Transition.
During this time, the cycle length between the cold and warm ice ages changed from 41,000 years to 100,000 years. But scientists never understood why.
This is the same time when, according to some theories, the ancestors of modern humans almost died out, perhaps down to only about a thousand people.
Scientists do not know if there is a connection between this near extinction and the climate, explains Prof. Barbante, but it shows that it is an unusual period that is important to understand better.
“What they will find is anyone’s guess but it will undoubtedly expand our window into our planet’s past,” Professor Joeri Rogelj of Imperial College London, who was not involved in the project, told BBC News.
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