/ 14 July 2017

Breakaway iceberg as big as Jamaica

Crack attack: A rift across the Larsen C Ice Shelf
Crack attack: A rift across the Larsen C Ice Shelf

Maps of the Southern Ocean will need to be redrawn after a titanic, 5 698km2, trillion-tonne iceberg broke away from an Antarctic ice shelf earlier this week.

Researchers from Project Midas, an initiative based at Swansea and Aberystwyth universities, confirmed the frozen mass – which rivals the island of Jamaica in terms of size – “calved” off the continent’s western coast sometime between Monday July 1 and Wednesday July 12.

It is difficult to convey the utter magnitude of the iceberg, likely to be named A68, with words alone. Should the sheet ever completely melt, it could fill 463-million Olympic-sized swimming pools.

For more comparison, reports from Reuters indicate the new water hazard is about 300 000 times the size of the 125m “snowflake” that sunk the Titanic.

A68 will spend the foreseeable future on a slow, wandering journey across the Weddell Sea; however, clima-tologists report its travels won’t notably affect ocean levels, because the sheet was floating prior to the break.

What’s more, Midas said rising global temperatures had no role in the episode. Regional satellite images dating back to the 1980s forecast the massive ice rift, and there appears to be no evidence that atmospheric warming accelerated the process.

Nevertheless, Martin O’Leary, a Swansea University glaciologist and Midas associate, warned against viewing the incident as wholly benign.

“Although this is a natural event, and we’re not aware of any link to human-induced climate change, this puts the ice shelf in a very vulnerable position. This is the furthest back that the ice front has been in recorded history.

“We’re going to be watching very carefully for signs that the rest of the shelf is becoming unstable,” he said when the ice break was announced.

O’Leary’s colleague, Adrian Luckman of Swansea University, said in the press release: “In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events, which may eventually lead to collapse – opinions in the scientific community are divided. Our models say it will be less stable, but any future collapse remains years or decades away.”

But in the short term, Luckman says A68 will “fundamentally change the landscape of the Antarctic Peninsula”.