For years, scientists have been monitoring a massive crack along the northernmost Antarctic ice shelf, which gradually grows bigger and bigger. It has been discovered to have grown by almost 11 miles — now almost the size of Delaware — and a dramatic break could occur around winter.
This occurrence, reported by British scientists this week, could trigger a much larger breakup and remove an enormous chunk of ice that prevents some of the continent’s glaciers from flowing into the ocean. The grim results: notably higher global sea levels, or about 4 inches higher.
Imminent Calving Event
A long-running rift in Larsen C ice shelf suddenly grew in December by 18 kilometers (11 miles) more, with only a final 20 km (12.4 miles) of ice is keeping the 5,000 square-kilometer (1,931 square-miles) section from drifting away. This size — larger than Rhode Island and nearly as huge as Delaware — would make the iceberg one of the top 10 largest ever recorded.
“When it calves, [the ice shelf] will lose more than 10 percent of its area to leave the ice front at its most retreated position ever recorded; this event will fundamentally change the landscape of the Antarctic Peninsula,” warned Project MIDAS in a statement.
The 350-meter (1,148 feet) thick Larsen C, floating on seas by West Antarctica’s edge and holding back the flow of glaciers feeding into it, has kept researchers on alert for years. The neighboring Larsen B disintegrated in 2002 after a similar event, while Larsen A collapsed back in 1995.
Project leader Adrian Luckman, a professor from Swansea University, told BBC News that he would be amazed if the ice shelf does not go in the next couple of months.
“It’s so close to calving that I think it’s inevitable,” he said, citing the Esa Sentinel-1 radar images they used to point to the extending rift.
Researcher Daniela Jansen of Germany’s Alfred Wegener Institute, which collaborates with Project MIDAS, agreed with the diagnosis.
“I think the iceberg will calve soon … Whether it will be months or maybe next year, I don’t know,” she said in an email to the Washington Post.
Is Global Warming the Culprit?
According to the researchers, this is a geographical rather than a climate situation, with the rift existing for decades now. They believe that further proof that warming has brought the ice shelf separation forward is needed.
Luckman and his team are expecting further calving events in the following months and years, leading up to an eventual collapse that still remains unpredictable.
The resulting iceberg from the ice shelf, floating on the sea, will not necessarily raise sea levels. But if the shelf further breaks up, it could led to glaciers flowing off the land behind it to accelerate their ocean passage — non-floating ice that would affect sea levels.
Estimates show, for instance, that if the ice that Larsen C is currently holding back suddenly enters the sea, water levels worldwide would increase by 10 centimeters (4 inches).
Back in November, an important Antarctic glacier called Pine Island Glacier was detected to be melting from inside out, suggesting the ocean is weakening ice on the continental edges.
But this is not the first research to confirm that the West Antarctic ice shelf is undergoing precarious changes. Only in October, two studies from NASA and the University of California suggested that the glaciers are retreating at an alarming rate because of the warm water beneath the ice shelf.
Antarctica is the geographical conglomerate that gathers over half of the world's frozen water.