The world’s biggest iceberg is about to enter the Southern Ocean after breaking free from the Antarctica more than two years ago.
The iceberg, called A68, measures nearly 2,300 square miles (6,000 square kilometres), making it about four times the size of Greater London and almost the same size as the US state of Delaware.
The enormous berg, which weighs one trillion tonnes, broke off from the Antarctic in 2017 and has been steadily travelling north ever since.
A68 is currently at about 63 degrees South latitude, but once it reaches the open ocean it’s likely to break down due to rougher waters.
It’s being carried north by currents and in the last year has started to accelerate in its journey northwards towards South Georgia, an island in the southern Atlantic Ocean.
The exit of iceberg #A68 from Antarctica 🇦🇶as seen from 2 years of @CopernicusEU #sentinel1 🛰️data pic.twitter.com/9ZCD6SqBFy
The berg broke away due to iceberg calving – the breaking away of masses of ice from the edge of a glacier.
Rising waters and air temperatures caused by global warming are triggering instabilities along the coasts of Antarctica and Greenland, accelerating melting and increasing the rates of calving.
However, scientists are hopeful that the berg breaks down as it travels further towards the equator and reaches choppier waters.
‘With a thickness to length ratio akin to five sheets of A4, I am astonished that the ocean waves haven’t already made ice cubes out of A68,’ Professor Adrian Luckman glaciologist and professor of geology at Swansea University, told the BBC.
‘If it survives for long as one piece when it moves beyond the edge of the sea-ice, I will be very surprised.’
Objects as big as the A68 have to be constantly tracked as they could pose an obstacle or even a threat to ships.
‘If it becomes a risk really depends on the route the iceberg follows, but I guess that also the smaller bergs will be tracked and their location will be communicated to ships,’ Sef Lhermitte, professor of geoscience and remote sensing at Delft University of Technology in the Netherlands, told MailOnline.
Since it calved from Antarctica’s Larson C ice shelf two years ago, the iceberg rotated 270 degrees and drifted 155 miles north as of last summer, carried by the ocean current known as the Weddell Gyre.
At 2,239 square miles (5,800 square km) it is roughly the size of Delaware (2,490 square m / 6,450 square km), or four times the size of Greater London 580 square m (1,500 square m), and its volume is twice that of Lake Erie – America’s fourth largest lake.
Professor Luckman had previously published an animation of the glacier’s movements between January 6, 2018 and July 10, 2019 on his blog.
‘For an object weighing around one trillion tonnes, Iceberg A68 appears to be quite nimble,’ Professor Luckman wrote.
‘Following a year of staying close to its parent ice shelf, in mid-2018 A68 became caught in the Weddell Gyre, a clockwise ocean current, which spun it through 270 degrees and carried it 250km north.
‘The iceberg is 100 miles (160 km) in length yet only 656 ft (200 m) thick – a similar ratio to a credit card – so it is surprising how little damage it has sustained in its journey so far.’
The fissure that caused A68 seemed relatively stable until January 2016, when it began to lengthen, according to the ESA, which reported the breaking off of A68 in July 2017.
When it first split, scientists expected the iceberg to quickly break apart and disintegrate, but it has remained mostly intact.
In March 2018, a British expedition intended to sample marine life at A68 – which contains about the same amount of water as Lake Ontario in North America – but it had to turn back due to thick sea ice that slowed them down.
Professor Luckman has also been observing the Pine Island Glacier in the West Antarctic, which is ridden with cracks and could split apart this year.
Major growth of cracks spotted by The European Union’s Copernicus EU Sentinel-2 satellites, with new fractures growing more 3.1 miles (5 km) in six days.
When it does break off, the 115 square mile (300 square km) berg will break up into pieces soon after, Professor Luckman said.