175 Km Long Crack In Antarctic Ice Shelf: Largest Iceberg In Our Lifetime Is Possible

(THIS ARTICLE IS COURTESY OF THE BBC)

Plane flies along Antarctica’s giant Larsen crack

The British Antarctic Survey (BAS) has released new footage of the ice crack that promises to produce a giant berg.

The 175 km-long fissure runs through the Larsen C Ice Shelf on the eastern side of the Antarctic Peninsula.

If it propagates just 20km more, a block of ice a quarter the size of Wales will break away into the Weddell Sea.

Scientists gathered the new video while recovering instrumentation that had been placed on the ice shelf.

Uncertainty about the stability of the region means researchers cannot set up camp as they would normally do, and instead make short visits in a Twin Otter plane.

The most recent sortie enabled the researchers also to fly along the length of the crack, which is 400-500m wide in places, to assess its status.

No-one can say for sure when the iceberg will calve, but it could happen anytime.

At 5,000 sq km, it would be one of the biggest ever recorded.

When it splits, interest will centre on how the breakage will affect the remaining shelf structure.

The Larsen B Ice Shelf further to the north famously shattered following a similar large calving event in 2002.

The issue is important because floating ice shelves ordinarily act as a buttress to the glaciers flowing off the land behind them.

In the case of Larsen B, those glaciers subsequently sped up in the absence of the shelf. And it is the land ice – not the floating ice in a shelf – that adds to sea level rise.

If Larsen C were to go the same way it would continue a trend across the Antarctic Peninsula.

In recent decades, a dozen major ice shelves have disintegrated, significantly retreated or lost substantial volume – including Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller, Jones Channel, and Wilkins.

Dr Paul Holland from BAS commented: “Iceberg calving is a normal part of the glacier life cycle, and there is every chance that Larsen C will remain stable and this ice will regrow.

“However, it is also possible that this iceberg calving will leave Larsen C in an unstable configuration. If that happens, further iceberg calving could cause a retreat of Larsen C.

“We won’t be able to tell whether Larsen C is unstable until the iceberg has calved and we are able to understand the behaviour of the remaining ice.”

The removal of the ice would also enable scientists to study the uncovered seabed.

When Larsen B broke away, the immediate investigation chanced upon new species.

Under the Antarctic Treaty, no fishing activity would be permitted in the area for 10 years.

The big bergs that break away from Antarctica are monitored from space.

They will often drift out into the Southern Ocean where they can become a hazard to shipping.

The biggest iceberg recorded in the satellite era was an object called B-15.

Covering an area of some 11,000 sq km, it came away from the Ross Ice Shelf in 2000.

Six years later fragments of the super-berg passed by New Zealand.

In 1956, a berg of roughly 32,000 sq km – bigger than Belgium – was spotted in the Ross Sea by a US Navy icebreaker. But there were no satellites at that time to follow-up.

Many of the bergs that break away from the Weddell Sea area of Antarctica get exported into the Atlantic. A good number get caught on the shallow continental shelf around the British overseas territory of South Georgia where they gradually wither away.

The study of the Larsen C Ice Shelf is led by Swansea University through its MIDAS Project, which involves BAS.

South GeorgiaImage copyright THINKSTOCK
Image caption The remnants of many such bergs end up at South Georgia

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos

Leaders Of England, Scotland, Whales And Northern Ireland Meet To Discuss Brexit

(THIS ARTICLE IS COURTESY OF THE SHANGHAI DAILY NEWS)

UK nations hold crucial Brexit talks

THE leaders of Scotland, Northern Ireland and Wales met British Prime Minister Theresa May yesterday to discuss what part the three nations will play in the Brexit process, a thorny issue that risks triggering a constitutional crisis.

May proposes setting up a new committee to give the three devolved governments, which have varying degrees of autonomy from London, a formal avenue to express views on how Britain’s future relationship with the European Union should work.

“The country is facing a negotiation of tremendous importance and it is imperative that the devolved administrations play their part in making it work,” May said in a statement released before the meeting.

At stake is the three-century union between England, where a majority voted to leave the EU, and Scotland, where a majority voted to stay.

Scottish First Minister Nicola Sturgeon said yesterday she was seeking “meaningful input” into the decision-making structure and wants each of the United Kingdom’s four assemblies to get a vote on the proposed negotiating package.

Sturgeon has said her government is preparing for all possibilities, including independence from the UK, after Britain leaves the EU.

In Northern Ireland, which also voted to keep EU membership, there are fears that Brexit could undermine a 1998 peace deal and reinstate a hard border with the Republic of Ireland.

Experts have warned of the risk of a constitutional crisis if May does not take into account the position of each of the UK’s four nations when conducting talks on the terms of Brexit.

“Imposing a Brexit settlement in the face of devolved opposition (while legally possible) would be a reckless strategy,” said the Institute for Government, an independent think-tank.

“Scotland, Wales and Northern Ireland cannot be treated like any other lobby or interest group. Equally, the devolved governments will have to accept that Westminster will have the final say,” it said in a report.

The new committee proposed by May would be chaired by Brexit minister David Davis and include representatives from the three devolved governments. May proposes that it should meet by the end of November and at least once more before Christmas.

Sturgeon has said Scotland wants to keep as many of the advantages of membership of the EU’s single market as it can and is looking for a bespoke deal to do so.