evidence: The sea-ice surrounding Antarctica is well below any previous recorded winter level, satellite data shows, a worrying new benchmark for a region that once seemed resistant to global warming. [...] Sea-ice forms in the continent's winter (March to October) before largely melting in summer, and is part of an interconnected system that also consists of icebergs, land ice and huge ice shelves - floating extensions of land ice jutting out from the coast. [...] Sea-ice has broken record minimums in summer for three of the past seven years, including February 2023.