Antarctic sea-ice at ‘mind-blowing’ low alarms experts
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.
“It’s so far outside anything we’ve seen, it’s almost mind-blowing,” says Walter Meier, who monitors sea-ice with the National Snow and Ice Data Center.
An unstable Antarctica could have far-reaching consequences, polar experts warn.
Antarctica’s huge ice expanse regulates the planet’s temperature, as the white surface reflects the Sun’s energy back into the atmosphere and also cools the water beneath and near it. Without its ice cooling the planet, Antarctica could transform from Earth’s refrigerator to a radiator, experts say.
The ice that floats on the Antarctic Ocean’s surface now measures less than 17 million sq km – that is 1.5 million sq km of sea-ice less than the September average, and well below previous winter record lows.
That’s an area of missing ice about five times the size of the British Isles
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 acts as a protective sleeve for the ice covering the land and prevents the ocean from heating up.
Dr Caroline Holmes at the British Antarctic Survey explains that the impacts of shrinking sea-ice may become evident as the season transitions to summer – when there’s potential for an unstoppable feedback loop of ice melting.
As more sea-ice disappears, it exposes dark areas of ocean, which absorb sunlight instead of reflecting it, meaning that the heat energy is added into the water, which in turn melts more ice. Scientists call this the ice-albedo effect.
That could add a lot more heat to the planet, disrupting Antarctica’s usual role as a regulator of global temperatures.
(BBC)
