Dr Katja Riedel of NIWA explains how ice cores are dated. The researchers often rely on events like volcanic eruptions to determine how old the ice is.
DR KATJA RIEDEL
We date ice cores by looking into historic events that we know how and when they happened. And a very good thing is volcanic eruptions. When you have a volcano erupting you have ash for example in the atmosphere. And this ash layer can travel around the globe, and then also is deposited in Antarctic ice cores. So you might be able to see a kind of darkish layer in an ice core and then you know exactly when this volcanic eruption was, and that is how you date your ice.
When we put together all what we find out about gas concentrations, about gas isotopes, what we’re looking for is information is where these greenhouse gases came in the past. How this change in greenhouse gas concentrations led to a different climate on Earth. Cause from the oxygen isotopes we also can have an idea of what the temperature was at the Earth. So we really see how temperature and greenhouse gas concentrations work together, and that will help us to understand how nowadays concentrations of greenhouse gases, which are increasing, work together with climate.