It was a year ago at this time that Antarctica’s Larsen C Ice Shelf gave birth to Iceberg A-68, one of the largest chunks of ice ever recorded. A new timelapse video made from satellite imagery shows the rift, calving and subsequent journey of the iceberg over the past 12 months.
Iceberg A-68 is the sixth largest iceberg ever recorded. At the time of calving, the 5800 square km iceberg weighed about 1000 billion tonnes, and encompassed an area roughly half the size of Sydney.
Freed from the Larsen C Ice Shelf, A-68 began to slowly drift north — slowly being the key word. As the new timelapse shows, this massive chunk of ice is in no rush.
Adrian Luckman and Martin O’Leary from Project MIDAS, a UK-based Antarctic research project that’s investigating the effects of climate change on the Larsen C ice shelf, say the iceberg hasn’t drifted far on account of dense sea-ice cover in the Weddell Sea.
“The iceberg has been pushed around by ocean currents, tides, and winds, and its northern end has repeatedly been grounded in shallower water near Bawden Ice Rise,” write Luckman and O’Leary in a statement.
“These groundings led eventually to further pieces of the iceberg being shattered off in May 2018.”
The new pieces aren’t large enough to be given their own identification labels, but the total area lost from A-68 in May alone was about the size of a small city, the researchers write. Over time, the iceberg will continue to inch northward toward the open sea, a process that could take decades.
Scientists estimate that A-68 lost about 12 per cent of its total mass over the past year. Even so, it’s still huge.
The calving of Larsen C last July kindled a debate among scientists as to the cause. Some scientists claim it’s a natural, cyclical process, whereby ice shelves grow, decay and break free, while others, such as Eric Rignot, a scientist at NASA’s Jet Propulsion Laboratory, believe it’s “the response of the system to a warmer climate”.
Regardless, this is an area ripe for further investigation, as Antarctica serves as a canary in the coal mine, alerting us to the effects of human-induced climate change.