Saturday , July 24 2021

Climate change: A European team dealing with the "old ice" drilling in Antarctica



EPICA ice coreImage copyright
Laurent AUGUSTIN / CNRS

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The original EPICA project from 1996 to 2005 began with an 800,000-year-old ice core

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Officially, it is an "ambitious" project to get a continental atmosphere and a climate that stretches over 1.5 million years.

The European Consortium will go to Antarctica in December to start deep into the eastern ice sheet of the continent.

The goal of the group is to pull out the core of the material for almost 3 km.

Scientists hope that this can lead to an explanation of why the Earth's Ice Age changed in the deep past.

Although at first glance it may seem like a rather esoteric search, researchers say that this is exactly the question of how much the world could warm up in the coming centuries.

"Something about 900,000 years ago. Ice cycles changed from every 40,000 years to every 100,000 years, and we don't know why," Dr. Catherine Ritz of the Grenoble German Institute of Geosciences, France.

"And that is quite important, because if we want to predict what will happen to the climate in the future with the increase of greenhouse gases, then we will have to use models and these models will be calibrated according to what happened in the past."

Dr Ritz spoke here at the General Assembly of the European Geosciences Union, where the site for the new drilling operation was officially announced.

It will be about 40 km southwest of the French and Italian research station known as Dome Concordia. The place is now called "Little Dome C".

Fourteen institutions from 10 countries will participate in the Beyond-EPICA project.

It may take about five years to completely remove the core, at least another year, to check the ice.

The estimated total cost of EUR 30 million (26 million pounds) will be covered by the European Union's science budget, Horizon 2020.

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R.Mulvaney / BAS

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Each bubble is a small time capsule that records the contents of an ancient atmosphere

How do ice cores record the climate of the past?

Antarctic ice is made up of snow, which has fallen for millions of years on the continent.

Since this ice was pressed, it captures air bubbles. These small gas pockets are a direct snapshot of the atmosphere.

Scientists can read, for example, carbon dioxide and other heat trapping components such as methane.

Analyzing atoms in water ice molecules, which include gases, also indicates the temperatures that remained during precipitation.

Currently, the oldest continuous core of ice ever drilled comes from the previous efforts of Dome C, the European project for the Ice Corridor Antarctica (EPICA).

It took place between 1996 and 2004 and pulled out a 10 cm ice cylinder, which was 2,774 m long.

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Media signaturesDr Rob Mulvaney: "We must understand why we are now living in a 100,000 year world"

What did this previous ice core reveal?

The old EPICA core contained 800,000 years of temperature and atmospheric carbon dioxide.

These markers were considered moving in the blocking stage. When the Earth entered the Ice Age and the temperature dropped, the concentration of greenhouse gases in the atmosphere would also decrease. And when the climate got down again, CO2 grew in parallel.

These cycles occurred approximately every 100,000 years at the core of EPICA – a phase that is likely to be associated with slight changes in the Earth's orbit eccentric (the larger or smaller ellipse) around the Sun.

But from an alternative to the climate record of the past, which is deciphered from ocean sediments, it is recognized that the deeper ice age was much shorter – about every 41,000 years.

This is a period of time in which the predominant way is the way the Earth slanted back and forth on its axis. But why did the switch happen, no one really sure.

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The previous ice core temperature and carbon dioxide moved in the blocking stage

What could be the reason for the shutter?

The orbital changes described above change the extent to which solar energy reaches the Earth, reflecting global temperature fluctuations of 1.5 degrees Celsius.

But the ice age – from minimal to maximum – includes a six degree change. This means that the game needs to have reinforcement processes.

The differences in the mixture of greenhouse gases and levels in the atmosphere will undoubtedly be part of the story, and the Beyond-EPICA ice core, if it can reach back to 1.5 million years, will unveil this particular investment. However, there are certainly additional factors.

"In my personal opinion, the best candidate is the internal climate system mechanism associated with changes in ice volume on Earth," said Professor Olaf Eisenen, project coordinator at the German Alfred-Wegener Institute.

"If you change the volume of ice, you will also change the sea level and ocean circulation. But something that we call the average pleistocene transition.

"CPM managers are still discussing and understanding the basic knowledge of the climate system."

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Media signaturesThe survey included the creation of a base stone radar map under Dome C

Has Europe chosen the right location?

Many countries have been looking for a place to sow the oldest core of ice, including America, Russia, China, Japan and Australia. Europe is the first project to be implemented during the implementation phase.

In terms of logistics, the site is very helpful in approaching an existing research base, but Little Dome C was only approved after three years of careful research.

The teams pull the radar tools back and forth over the ice to show the layers below on the map. They even dropped the test holes to see how warm it could be on the ice sheet base.

One of the most difficult problems is that the heat coming from the base area will melt the lower layers and the older ice layers. This is a very real risk, the deeper the drilling, the cooler the temperatures are always closer to the surface of the ice sheet.

"The system will be 4 m long when it appears," explained Robert Mulvaney of the British Antarctic Survey. "We will cut it into 1 m sections at Little Dome C and then move to Concordia Station.

"At the station, we cut the halves by half. Half of us will leave Antarctica as a long-term archive (we won't have to pay the cost of the freezer!) And the other half will return to Europe for analysis.

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R.Mulvaney / BAS

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In his radar survey, the Little Dome C field team ran 2500 km


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