The Antarctic Ice Sheet covers 5.4 million square miles. Antarctic ice amounts to 90 per cent of all the ice on the planet and between 60-70 per cent of all of the world’s fresh water. If the entire Antarctic Ice Sheet melted, global sea levels would rise by about 200 feet, putting the world’s coastal cities underwater.
In winter, surface waters near Antarctica freeze to form sea ice. When sea ice forms, salt is forced out of the forming ice (brine rejection), making the water below the ice more saline and therefore denser. In a few places around Antarctica, the resulting cold and salty waters are sufficiently dense to sink to the deep ocean and form Antarctic bottom water. This dense bottom water sinks and spreads northwards to supply oxygen to the deep layers of the ocean, and warmer waters flow south to replace it. The southwards flow at mid-depth also compensates for the northwards flow of lighter waters. The formation and circulation of Southern Ocean water masses provide a key link in the global ‘conveyor belt’ of ocean currents that controls climate by transporting heat and other properties.
Picture Credit : Google
