What affects the thinning of sea-ice?

Prof. Dr Christian Haas, Head of the Sea Ice Physics Section at the Alfred Wegener Institute and Professor at the Institute for Environmental Physics at the University of Bremen.

Sea Ice


The sea ice in the Arctic and Antarctic is a major component of the global climate system, and changes in its thickness and snow cover are important indicators of climate change. The thickness of the ice depends not only on thermodynamic factors like heat in the air and water, or radiation; winds and ocean currents also play an important role by constantly moving and deforming the ice, leading to the creation of thick pressure ridges. As a result, ice thickness and snow cover are highly variable.

Due to the extreme warming of the Arctic, there is less ice there, and the remaining ice has become thinner. However, it is still unclear which of the above processes contribute the most to the disappearance of the ice. In contrast, in the Antarctic the sea ice has changed little and its thickness has largely remained the same. For thirty years, we have conducted ice-thickness measurements in the Arctic and Antarctic, which are among the most accurate and detailed in the world. To do so, we use measurements on the ground, from the air and from satellites, and continually improve them. This allows us to differentiate between thermodynamic and dynamic changes in thickness and to better identify the atmospheric and ocean processes that contribute to the observed changes. Furthermore, we investigate the consequences of sea-ice retreat on the climate and ecosystem, and on human use of the polar regions, e.g. in the context of shipping.