Computer-generated models of prehistoric glaciation do not just cast a new light on the current changes being experienced in the Arctic and Antarctic. They also contribute to predicting our climate in the future. Glaciation modeller Nina Kirchner is originally a mathematician, but prefers to take an interdisciplinary approach.

 Nina Toro

Nina Kirchner
 
Foto Erik Kirchner
 

 

In recent years researchers have discovered that the ostensibly compact ice covering the Antarctic is moving, and is doing so rapidly. Movement of ice of up to a thousand meters a year has been measured, an enormous speed in this context, which primarily involves movement of ice from the centre to the outer edges of the ice sheets.
A worst case scenario is that the movement of the ice will accelerate and that what is known as the ice-shelf, which rests on the Antarctic Ocean, will eventually disappear. This would result in giant ice floes cascading out into the ocean – with far-reaching climate effects. Researchers the world over are trying to determine if this will happen.
Computer modelling is an important tool in this work. Since the 1950s scientists have used mathematical equations to generate models of ice sheets and glaciation. For a long time models have focussed on the internal parts of the glacial ice sheets, where the ice is thick and the movements are small. Nina Kirchner is one of the researchers developing models to describe the more dynamic behaviour of the edges of the ice sheets.

"Everything that is happening and that is so dramatic about the ice, both in Greenland and in the Antarctic, is happening along the edges. But these processes are not yet included in our models," says Nina Kirchner.

Many of those who study mathematics become engineers or enjoy careers in insurance or banking. Nina Kirchner's aspirations are different. When she studied mathematics in Switzerland at the beginning of the 1990s she had a professor who also taught theoretical glaciology. That was where her interest in glaciation and ice began.
Five years ago her sister – who lived in Sweden – told her that the newly inaugurated climate research centre, the Bert Bolin Centre, was looking for glacial modellers. For Nina Kirchner this was a dream job. She strives for dialogue and the meetings of different disciplines and at the centre she has close collaborations with geologists and geoscientists. But finding a mutual arena, where researchers from different backgrounds and terminologies have a deep understanding of each other, has taken time. The collaborations were initially plagued by misunderstandings.

"Now we have begun to breach our respective subject boundaries and can really begin to combine our core specialities. This then brings something new to the research. It is truly fascinating," Nina Kirchner explains.

Nina Kirchner is driven in the first instance to learn more about today's ice sheets. But her computer models will also provide a piece of the jigsaw in the study of climate in the future. To determine if a historical model is correct she calibrates this against current conditions, with the assistance of satellite images and geological findings. If the model holds, it can then also be used to study possible future developments.
In the winter of 2010 Nina Kirchner took part in a major Antarctic expedition. Thanks to marine geology field studies along the Antarctic coast, researchers gleaned more knowledge about how movement of the ice far back in time contributed to great masses of ice collapsing into the ocean.

"Such previous collapses help us to understand what is going on in the Antarctic now and how this can affect the climate of tomorrow," says Nina Kirchner.