'Precipitous' fall in Antarctic sea ice since 2014 revealed
Plunge is far faster than in Arctic and may lead to more global heating, say scientists
Guardian
Damian Carrington Environment editor
Published: 15:00 Monday, 01 July 2019
The vast expanse of sea ice around Antarctica has suffered a “precipitous” fall since 2014, satellite data shows, and fell at a faster rate than seen in the Arctic.
The plunge in the average annual extent means Antarctica lost as much sea ice in four years as the Arctic lost in 34 years. The cause of the sharp Antarctic losses is as yet unknown and only time will tell whether the ice recovers or continues to decline. But researchers said it showed ice could disappear much more rapidly than previously thought. Unlike the melting of ice sheets on land, sea ice melting does not raise sea level. But losing bright white sea ice means the sun’s heat is instead absorbed by dark ocean waters, leading to a vicious circle of heating.
Kaitlin Naughten, a sea ice expert at the British Antarctic Survey, said:
“Climate change is affecting the winds, but so is the ozone hole and short-term cycles like El Niño. The sea ice is also affected by meltwater running off from the Antarctic ice sheet,” she said. “Until 2014, the total effect of all these factors was for Antarctic sea ice to expand. But in 2014, something flipped, and the sea ice has since declined dramatically. Now scientists are trying to figure out exactly why this happened.”
Prof Andrew Shepherd at Leeds University in the UK said: “The rapid decline has caught us by surprise and changes the picture completely. Now sea ice is retreating in both hemispheres and that presents a challenge because it could mean further warming.” He said it would also be important to find if the ice’s thickness has changed, as well as its extent.
https://www.theguardian.com/world/2019/jul/01/precipitous-fall-in-antarctic-sea-ice-revealed?CMP=Share_iOSApp_Other
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