Sea ice

Sea ice typically covers up to 15 million square kilometres of the Arctic Ocean, and up to 19 million square kilometres of the Southern Ocean around Antarctica, during their respective winter seasons. This seasonal cycle of sea ice is one of the most dynamic components of the Earth's climate system.

Satellite records show a constant downward trend in the area covered by Arctic sea ice during all seasons, in particular in summer, with the minimum recorded occurring in the autumn of 2012.

ESA’s CryoSat mission is dedicated to measuring the thickness of polar sea ice and monitoring changes in the ice sheets that blanket Greenland and Antarctica.