Revealing climate secrets contained in Antarctic ice
The frozen Antarctic ice sheet contains below it a unique record of climate history. Using data from ice cores extracted from this polar region, EU researchers have been able to piece together the climate of the past 800 000 years. “Analysis of these ice cores tells us that while concentrations of greenhouse gases have oscillated over time, this has always occurred within constrained boundaries,” explains Beyond EPICA(opens in new window) project coordinator Carlo Barbante from the Institute of Polar Sciences(opens in new window) of the National Research Council(opens in new window) in Italy. “It is only in the last 200 years that concentrations of CO2 and methane have gone off the chart.” Another key discovery has been that over 800 000 years ago, glacial cycles appear to have changed from occurring every 40 000 years to every 100 000 years. “Something happened during that period of time,” says Barbante. “In order to better understand this though, we realised that we needed to find even older ice.”
Accessing ice as old as 1.2 million years
This led to several years spent travelling across the Antarctic plateau, looking for suitable sites where drilling could take place. Eventually, a location about 35 km away from the Italian-French research station Concordia was found. The Beyond EPICA project, which built on this previous EU-funded work, was able to get under way. “We started drilling in 2021 and have had some very successful seasons,” adds Barbante. “In January 2025, we finally reached the bedrock at a depth of 2 800 metres. This has given us access to ice as old as 1.2 million years, and perhaps even older.” The successful extraction of these ice cores is a significant result. Analysis will give scientists insights into Earth’s atmosphere from over a million years ago. Some preliminary measurements have already been carried out on-site, confirming the age of the ice, but more detailed measurements will now take place across laboratories in Europe.
Analysing ice cores to recreate climatic conditions
“Beyond EPICA samples have finally arrived in Bremerhaven after an incredible 76-day journey at sea,” says Barbante. “All temperature protocols were respected, and the samples are ready to be prepared for analysis in the coming months.” The ice cores will now be carefully distributed to participating laboratories for analysis. Some of these cores will be melted, with water running into channels that feed into measurement devices. From this, researchers will look at the isotopic composition of water molecules, dust content and chemistry. This data will help them to reconstruct the atmosphere at this point in time. Other researchers will analyse air bubbles trapped in the ice, to analyse the composition of greenhouse gases.
Understanding our past to inform our sustainable future
For Barbante, this work of looking into our distant past is absolutely critical to informing a sustainable future. “Today, we live with high concentrations of greenhouse gases,” he notes. “By looking at times in the past when conditions were similar, we can see how temperatures were impacted, and how climate systems reacted.” Another benefit is that the accuracy of climate models can be calibrated by using data from the past. Researchers can get a sense of how useful these models might be in predicting the future. The team is hopeful that this work will shine a light onto why glacial cycles appear to have changed over 800 000 years ago, and open up new ideas for climate mitigation. “By understanding how climate worked in the past, we can put into better perspective what is happening today, and what is likely to happen in the future,” concludes Barbante.