Cracks and fissures stoke fears of breakup that could lead to half-metre rise in global sea levels – or more
Twenty years ago, an area of ice thought to weigh almost 500bn tonnes dramatically broke off the Antarctic continent and shattered into thousands of icebergs into the Weddell Sea.
The 1,255-sq-mile (3,250-sq-km) Larsen B ice shelf was known to be melting fast but no one had predicted that it would take just one month for the 200-metre-thick behemoth to completely disintegrate.
Glaciologists were shocked as much by the speed as by the scale of the collapse. “This is staggering. It’s just broken apart. It fell over like a wall and has broken as if into hundreds of thousands of bricks”, said one.
This week, ice scientists meeting in New Orleans warned that something even more alarming was brewing on the West Antarctic ice sheet – a vast basin of ice on the Antarctic peninsula. Years of research by teams of British and American researchers showed that great cracks and fissures had opened up both on top of and underneath the Thwaites glacier, one of the biggest in the world, and it was feared that parts of it, too, may fracture and collapse possibly within five years or less.
Thwaites makes Larsen B look like an icicle. It is roughly 100 times larger, about the size of Britain, and contains enough water on its own to raise sea levels worldwide by more than half a metre. It contributes about 4% of annual global sea level rise and has been called the most important glacier in the world, even the “doomsday” glacier. Satellite studies show it is melting far faster than it did in the 1990s.
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