Scientists drill their way to past climate data

Reconstructing the climate of the Antarctic over the past 20 million years is the goal of an international team of scientists, as it drills its way through 1,000 metres of sediment on the
Antarctic sea floor.

The 50 researchers, who come from Germany, Italy, the US and New Zealand, are participating in the ANDRILL (Antarctic Geological Drilling) project, which is studying how the Antarctic climate
has changed over time and what impact these changes have had on the polar region’s floating ice shelves. By finding out how the ice shelves responded to warm periods in the past, scientists
hope to be able to predict how climate change will affect the existing ice shelves.

The question is an important one; when the floating ice shelves melt, the glaciers on land flow into the sea faster, and when they melt, sea levels rise.

‘Last year we drilled a 1,285 metre long sediment core under the Ross ice shelf,’ said project participant Gerhard Kuhn of the Alfred Wegener Institute for Polar and Marine Research. ‘Now we
want to go back a further five million years and find out about a period during which the climate was even warmer.’

Drilling on ice that is itself floating on the sea brings with it a range of challenges. The ice, which is eight metres thick, cannot support the weight of the drilling machinery, so divers had
to place buoyancy supports underneath the ice. Furthermore, as the Antarctic summer approaches, the ice will get thinner, and by the beginning of December the drilling camp on the ice will have
to be dismantled.

However, the reward makes overcoming these challenges worthwhile. The sediment layers of the sea floor contain vast amounts of information on the region’s climate, going back millions of years.
The sediment cores should also provide information on how far the sea ice once reached. If stones are found in the sediment, they must have been transported in glacier ice from the Antarctic
continent, meaning that the region was covered in ice at that point in time.

The ANDRILL project also has a strong educational component. A group of nine teachers from the countries involved in the project will be working at the drill site together with the scientists.

‘In the long term I would like to encourage teachers to integrate the polar regions more strongly into their lessons,’ said Dr Rainer Lehmann, a German geology teacher who is participating in
the project. ‘The Earth’s ice caps are unique habitats and climate archives, which are currently undergoing major changes. Their significance for our lives in Europe should be much more
strongly integrated into lesson plans in the future.’

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