ESA's ice mission   CryoSat determines variations in the thickness of floating sea-ice so that seasonal and interannual variations can be detected. The satellite also surveys the surface of continental ice sheets to detect small elevation changes. Information on precise variations in ice thickness will further our understanding of the relationship between ice and climate change.   The polar oceans each year experience the formation and then melting of vast amounts of sea ice. At the North Pole, an area the size of Europe melts every summer and then freezes again the following winter. The thickness of this sea ice plays a central role in polar climate because it moderates heat transport by insulating the ocean from the cold polar atmosphere.   Data from ESA’s CryoSat mission will lead to a better understanding of how the volume of ice on Earth is changing and, in turn, a better appreciation of how climate and ice are linked. Last update: 26 October 2010