Predicting tomorrow’s climate using the oldest ice on the planet

“This is a historic moment for climate and environmental science,” says Carlo Barbante, coordinator of the European Beyond EPICA project.External link. Ice extracted in Antarctica could reveal the link between the carbon cycle and the temperature of our planet, continues the professor of analytical chemistry at Ca’ Foscari University in Venice.

For the first time, scientists will be able to get a precise idea of ​​the evolution of the climate over the past 1.2 million years, says a press releaseExternal link from January 9. Using the collected ice, they hope to understand past climate changes that have remained largely unexplained until now.

“This is a historic moment for climate and environmental science. »

Carlo Barbante, Beyond EPICA

The Beyond EPICA project, in which Switzerland also participates, was launched in 2009 and is coordinated by the Institute of Polar Sciences of the Italian National Research Council. It aims to reconstruct part of the Earth’s climatic history through the analysis of ice samples taken at a depth of nearly 3 kilometers in Antarctica.

Thanks to this project, science can deepen our understanding of how the climate system responds to changes in greenhouse gases, Carlo Barbante explains to swissinfo.ch. This will improve future climate models and projections.

“Our past contains a lot of our present and our future: to understand the climate of tomorrow, we must understand the hidden mechanisms of how our Earth system works,” he explains.

>> À lire: The evanescent treasure of the Swiss glaciers

1.2 million years of climate history in an ice core

Researchers from twelve scientific institutions, including the University of Bern, extracted the ice core at Little Dome C, an isolated field on the Antarctic plateau, near the Franco-Italian Concordia station. The international team worked for more than 200 days over a four-year period, with temperatures averaging -35°C in summer.

Aerial view of the Little Dome C drilling site in Antarctica.

PNRA_IPEV

The drilling reached a record depth of 2,800 meters, at the point where Antarctic ice meets rock. The extracted ice represents an unparalleled record of the Earth’s climatic history, underlines Carlo Barbante.

Air bubbles trapped in the ice provide information about atmospheric temperatures and concentrations of CO2, methane and other greenhouse gases over the past 1.2 million years. Current knowledge allows us to go back in time “only” 800,000 years.

Specifically, the Beyond EPICA ice core will provide unprecedented insights into the Middle Pleistocene transition. During this period between 900,000 and 1.2 million years ago, the extent of ice crusts in the Northern Hemisphere changed dramatically, which had a profound impact on climate. .

The interval between one glaciation and the next has lengthened considerably, from around 40,000 to 100,000 years. The reason for this change is “one of the most complex mysteries in climate science,” according to the University of Bern.

>> The following video shows how ice samples are extracted in Antarctica:

The “determining” participation of Switzerland

The ice samples will arrive in Europe towards the end of March. They will be analyzed by laboratories in Germany, Switzerland, Italy, France and Great Britain.

The University of Bern will use an innovative techniqueExternal link laser beams, which it developed in collaboration with the Federal Laboratory for Materials Testing and Research (Empa). This technique makes it possible to measure the greenhouse gases contained in the ice with extreme precision, without contaminating the samples with ambient air and without melting the ice. The analysis only requires a one-centimeter-thick ice sample.

Thanks to this pioneering work, it will be possible to carry out greenhouse gas measurements with the necessary precision and temporal resolution in these old ices, according to Hubertus Fischer, professor of experimental climate physics at the University of Bern and the one of the leaders of the Beyond EPICA project.

Switzerland’s participation is “decisive” in the project, and not only in terms of financing, underlines Carlo Barbante. The Swiss contribution amounts to 3 million Swiss francs, that of the European Commission to 11 million euros (10.3 million Swiss francs).

The technique for quantifying CO2 present in tiny air bubbles trapped in the deepest layers of ice, he explains, will also be useful to other international laboratories in the United States, China, Korea South and Australia.

Proofread and verified by Virginie Mangin. Translated from Italian using DeepL by Emilie Ridard/ptu.