PLEA Network

1 August 2023, The Conversation: Antarctica is missing a chunk of sea ice bigger than Greenland – what’s going on? Deadly heatwaves, raging wildfires and record global temperatures are upon us. But far from the flames, at the southernmost tip of the planet, something just as shocking is unfolding. It’s Antarctic winter, a time when the area of floating sea ice around the continent should be rapidly expanding. This year though, the freeze-up has been happening in slow motion. After reaching a record low minimum extent this summer there is now an area of open ocean bigger than Greenland. If the “missing” sea ice were a country, it’d be the tenth largest in the world. Who cares about Antarctic sea ice? In the face of more immediate climate concerns, why does Antarctic sea ice matter? Floating sea ice is a pivotal climate puzzle piece. Without it, global temperatures would be warmer because its bright, white surface acts like a mirror, reflecting the sun’s energy back to space. This keeps the Antarctic – and by extension, the planet – cool. Antarctic sea ice also plays a particularly important role in controlling ocean currents and may act as a buffer that protects floating ice shelves and glaciers from collapsing and adding to global sea levels. In short, the loss of Antarctic sea ice matters for the whole planet. Southern sea ice: a short history. Every year Antarctic sea ice undergoes a transformation: from its summer minimum in February, its area increases more than sixfold during the winter freeze-up which reaches its height in September. A clear way to monitor the health of Antarctic sea ice is to track these peaks and troughs. Records began in 1979 and until 2015, the yearly average extent of frozen sea around Antarctica was increasing ever so slightly. Yet in the past seven years, Antarctic sea ice has changed dramatically. Read more here