An international research team involving the Alfred Wegener Institute (AWI) in Bremerhaven has recovered a 2.8-kilometer-long ice core in the Antarctic. According to the AWI, it represents at least 1.2 million years of continuous climate history. "This is the longest continuous record of our past climate from an ice core and can show the connection between the carbon cycle and the temperature of our planet," said Carlo Barbante, coordinator of the "Beyond Epica - Oldest Ice" project.
The longest continuous ice core to date was also recovered in the Antarctic in 2004. It dates back around 800,000 years. The ice in such drill cores contains air with the concentrations of carbon dioxide and methane present at the time of inclusion. These values allow conclusions to be drawn about the climate of the epoch in which the respective bubble was formed.
Enigma of climate history
Among other things, the researchers hope to be able to solve a particular puzzle in climate history: Around one million years ago, the rhythm of warm and cold periods changed on Earth. While the periods previously alternated every 41,000 years, the period was suddenly extended to 100,000 years. Understanding the frequency of ice age cycles is also important for the future of the planet, explained AWI glaciologist Frank Wilhelms.
The "Little Dome C" drilling camp is located on a central Antarctic plateau at an altitude of 3,200 meters above sea level, where the average summer temperature is minus 35 degrees, according to AWI data. The ice core will be transported away in sections on board an icebreaker. Maintaining the cold chain at minus 50 degrees is a challenge. Special refrigerated containers have been constructed for this purpose. The ancient ice is being examined in the AWI ice laboratory in Bremerhaven.