1. Institute of Geography and Oeschger Center for Climate Change Research, University of Bern, Bern 3012, Switzerland
2. Climate System Research Center, Department of Geosciences, University of Massachusetts Amherst, Amherst 01003, United States
3. Department of Chemistry and Biochemistry and Oeschger Centre for Climate Change Research, University of Bern, Bern 3012, Switzerland
4. Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf 8600, Switzerland
5. Department of Earth Sciences, ETH Zürich, 8006 Zürich, Switzerland