The seminar has been organized for the Ph.D. Program in Science and Management of Climate Change.

Lecturer
Prof. Joergen Peder Steffensen
(Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark)

Temperatures in the interior of the Greenland ice sheet only reach melting point a few times per century. Most of snow falling there never melts, and is buried by subsequent snow falls. As the snow layers sink, they are compressed into glacier ice. An ice core drilled at the crest of the Greenland ice sheet contains thousands of snowfalls in an undisturbed sequence with the oldest layers in the bottom end the youngest layers on top. Greenland ice is so clean that very few features are visible, so in order to perform stratigraphic analysis we need to perform measurements. I will discuss which physical and chemical measurements are employed to obtain information on past composition of atmospheric aerosols and gases and to resolve individual annual layers for annual layer counting and dating of the ice core profile. Certain atmospheric events, such as volcanic eruptions or changes in Solar activity show up in the ice cores as events. If these events can be found in other geological records, such as marine sediments, lacustrine sediments, speleothems or corals, then we may link the Greenland climate curve and dating to these records by synchronization. This allow us to discuss whether a climate change in Greenland 14,000 years ago happened at the same time in Italy, China or U.S.