COLD FACTS

Iceberg break so significant it will change Antarctic coastline: scientist

Scientists announced Wednesday that one of the biggest icebergs in recorded history just broke loose from Antarctica. It consists of almost four times as much ice as the fast melting ice sheet of Greenland loses in a year. It is expected to be given the name “A68” soon, scientists said.

THE BREAK

The break was detected by one NASA satellite instrument and confirmed by the European Space Agency. The iceberg contains so much mass that if all of it were added anew to the ocean, it would drive almost 3 mm of global sea level rise. In this case though, the ice was already afloat so there won’t be a substantial change. However, scientists fear that the ice loss could speed up the outward ice flow of the remainder of the Larsen C ice shelf, which could indeed increase sea level — but glaciers in this region only have the potential to raise seas by about a centimetre.

UNSTABLE SHELF

The Project MIDAS group, a research group at Swansea and Aberystwyth Universities in Wales that has been monitoring the situation, said Wednesday that the effect of the break is to shrink the size of the floating Larsen C ice shelf by 12 per cent.

UNCERTAIN FUTURE

“The iceberg is one of the largest recorded and its future progress is difficult to predict,” said Adrian Luckman, the lead MIDAS researcher and an Antarctic scientist at Swansea University, in a statement. “It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters.” There is no expected immediate effect on shipping, Luckman said by email.

NEW COASTLINE

The change is large enough that it will trigger a redrawing of the Antarctic coastline, says Ted Scambos of the National Snow and Ice Data Center. It means that the Larsen C ice shelf, previously the fourth largest of its kind in Antarctica, is now only the fifth or sixth largest, he said.

OTHER BIGGIES

Even larger icebergs than this have broken off of Antarctica in the past, however, including a more than 10,400 square kilometre berg, famously dubbed B15, in 2000. That was almost twice the size of this one and broke off the Ross Ice Shelf, Antarctica’s largest floating ice body. It was the biggest iceberg ever recorded. Larsen C also lost an even larger piece in 1986, Scambos said, but that occurred after the shelf had grown and extended much farther out into the Weddell Sea than it does now.