https://www.news.com.au/technology/environment/climate-change/antarctic-time-bomb-waiting-to-go-off-could-wash-away-cities-scientists-warn/news-story/55b79907be015b68979ad70c2138e4d1
Antarctic ‘time bomb’waiting to go off could wash away cities, scientists warn
By historical data, Earth’ssea levels should be nine metres higher than they are — and there’s a worryingtrigger that could see that happen.
What the warming ofAntarctica means for us
Earth’s sea levels should benine metres higher than they are — and dramatic melting in Antarctica may soonplug the gap, scientists warn.
They say global temperaturestoday are the same as they were 115,000 years ago, a time when modern humanswere only just beginning to leave Africa.
Research shows during thistime period, known as the Eemian, scorching ocean temperatures caused acatastrophic global ice melt. As a result, sea levels were six to nine metreshigher than they are today.
But if modern oceantemperatures are the same as they were during the Eemian, that means our planetis “missing” a devastating sea rise.
If oceans were to rise byjust 1.8 metres, large swathes of coastal cities would find themselvesunderwater, turning streets into canals and completely submerging some buildings.
Scientists think sea levelsmade this jump 115,000 years ago because of a sudden ice collapse inAntarctica.
The continent’s vulnerableWest Antarctic ice sheet — which is already retreating again today — released alot of sea level rise in a hurry.
“There’s no way to get tensof metres of sea level rise without getting tens of metres of sea level risefrom Antarctica,” said Dr Rob DeConto, an Antarctic expert at the University ofMassachusetts in the US.
His team createdstate-of-the-art computer models that showed how Antarctic ice responded towarm ocean temperatures during the Eemian.
They showed two processes,called marine ice cliff collapse and marine ice sheet instability, rapidlymelted the West Antarctic ice sheet.
They exposed thick glaciersthat formed part of the ice sheet to the ocean, meaning the ice blocks floatedout to sea more quickly. Here they quickly melted, adding thousands of tonnesof water to the world’s oceans.
Scientists warn if iceshelves in Antarctica undergo similar processes, it could spell disaster forEarth. Combined with melting in Greenland, we could see sea levels rise byalmost two metres this century.
In the next century, iceloss would get even worse.
Lastmonth, NASA warned Antarctica’s Thwaites glacier could collapse within decadesand “sink cities”.
“What we pointed out was ifthe kind of calving that we see in Greenland today were to start turning on inanalogous settings in Antarctica — Antarctica has way thicker ice, it’s a waybigger ice sheet — the consequences would be potentially really monumental forsea level rise,” Dr DeConto said.
Last month, NASA warnedAntarctica’s Thwaites glacier could collapse within decades and “sink cities”after the discovery of a 300-metre doomsday cavity lurking below the ice block.
If you fancy a fright, checkout this sealevel “doomsday” simulator if you’d like to know whether your home would be wiped out by rising
World leaders have beenwarned that civilisation could collapse.
