Ice sheets: can the heat harm them?

Prof. Dr Olaf Eisen, glaciologist at the Alfred Wegener Institute and professor at the University of Bremen.

Ice sheets


Ice dynamics in climate change

The ice masses of Greenland and Antarctica are no inert or rigid entities, but surprisingly changeable. They permanently interact with their environment – that primarily means the ocean and the atmosphere – and react to changes much faster than one had believed just 25 years ago. Today, better research technology and modern satellite-based observation systems put us in the position to perform fundamental investigations of the ice masses on site as well as keeping an eye on them continuously from the distance. In such a way we developed a solid understanding of their role in the climate system of the Earth and can better retrace reasons for their changes.

This statement is true for the past, which was dominated by changes between glacial and interglacial periods, as well as for the presence, in which men-made global warming is breaking all known speed records of change. That’s exactly the point where contemporary objectives of ice sheet research put their lever: How quickly will ice sheets react to warmer oceans? How does melting at their surface influence their total mass balance – does more ice melt than is renewed every year by snow fall? Which role play the conditions and the base of the ice for the speedy ice streams and did they change their behaviour in the past? Where can we find the oldest ice, with which we can reconstruct the climate of the past, more than one million years ago?

For all of these questions observations on site are essential. This begins with the determination of the ice thickness, continues with the inference of the crystal orientation fabric in larger depth and ends with the composition of the subsurface below the ice, both of which govern flow behaviour of ice. In the end, we hope to make conclusions about how ice masses will change in the decades to come under continuing climate change – and which threads will be emanate from them.