Jochen Schmitt and his colleagues, in their Sciencepublication present a unified picture of isotopic variations for the past 24'000 years derived from three independent records from two Antarctic ice cores. The primary challenges the researchers of the division for Climate and Enviromental Physics at the University of Bern had to overcome were technical. Samples from ice cores are small, making it difficult to make precise measurements. The OCCR researchers refined the existing technique of sublimating ice and coupled it with a sensitive mass spectrometer to measure carbon isotope ratios. "Schmitt et al. move the isotopic story forward with an important data set", writes Edward Brook in his comment of the paper. Up to now ice core carbon isotopic measurements have not been detailed or precise enough to find precise patterns in order to convincingly explain the carbon cycle from a glacial to an interglacial state. This could now change.
