Ice cores show that the increase in gas in the atmosphere is unique in the history of the earth.
The precise measurement was made using ice cores from the Antarctic. (Archive image)
Foto: Yuri Smityuk (Getty Images)
Climate deniers like to say that there have been leaps in CO₂ increases before. That’s right, replies a research team headed by Bern. But today’s ascent is six times bigger and almost ten times faster than the jumps at that time. That can be proven.
A new measurement technology developed at the University of Bern enables an unimaginably detailed insight into the past. Thanks to high-resolution measurements, past CO₂ concentrations in the atmosphere could be reconstructed more precisely than ever before using ice cores from the Antarctic.
Decisive for the unprecedented insights into the atmospheric composition around 330,000 to 450,000 years ago was not least the decades of experience of the Bernese researchers with the analysis of this climate archive. The results of the study were published in the journal Science.
Using the ice cores, the climate of the eight consecutive ice ages and warm periods of the last 800,000 years was reconstructed. It turned out that «rapid increases in CO₂ are a widespread characteristic of our climate system». And also during natural warm periods, of which it has always been assumed that their climate and CO₂ ratios were stable.
Historical leaps are not as bad as they are today
According to the first author of the study, Nehrbass-Ahles, there were always sudden increases when melting ice masses in Greenland or the Antarctic significantly disrupted the ocean circulation. “If the CO₂ in the atmosphere soared, changes in the circulation of the Atlantic could also be determined at the same time.”
Why the CO₂ concentration in the atmosphere rose sharply twice during warm periods has yet to be clarified, says the Bernese climate researcher Thomas Stocker, Nehrbass-Ahles ›doctoral supervisor and co-author of the study.
Natural CO₂ jumps make plans difficult
Even if these historical leaps were enormous, they are nothing compared to the man-made increase of the past ten years. According to Stocker, the strongest increase in the past was around 15 ppm (parts per million is the unit of measurement for atmospheric CO₂ concentration). This corresponds roughly to the increase that humanity is currently causing over a period of six years.
“At first glance, that may not seem very important,” says Stocker, “in view of the quantities of CO₂ that we are still allowed to emit in order not to lose the 1.5-degree climate target set in Paris But increases are definitely relevant. ” An additional increase in the greenhouse gas CO₂ triggered by global warming, as occurred in the past, could put even more pressure on mankind when it comes to climate protection.
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