The largest iceberg in the world is about to enter the open sea.
The A68 iceberg is a colossus that separated from the Antarctic Peninsula in 2017 and has been moving north since then. Now it is on the edge of the continent where the perennial ice is.
When it separated, the iceberg had an area of 6 thousand square kilometers. During the past two and a half years he has lost some ice, reaching a size of 5.8 km² (equivalent to the size of the Federal District).
Scientists say the A68 will not remain in one piece when it reaches the choppy waters of the Southern Ocean.
“I am surprised that the ocean waves have not yet turned the A68 into ice cubes,” says glaciologist Adrian Luckman of the University of Swansea in the United Kingdom. “It has a ratio of area to thickness equivalent to four stacked sulfite sheets.”
“If he survives long enough after moving beyond the limits of perennial ice, I will be very amazed,” he tells BBC News.
The A68 separated from the Larsen C ice shelf in July 2017. For a year, it barely moved, with its keel apparently attached to the ocean floor.
But winds and currents eventually pushed the iceberg north along the eastern coast of the Antarctic Peninsula. This summer, the movement accelerated rapidly.
Where you go?
The iceberg is following a very predictable path, according to scientists.
When passing beyond the peninsula, the gigantic block of ice should be pushed into the Atlantic Ocean, a path known to researchers as the Iceberg Corridor.
The largest iceberg ever recorded in modern times was an 11,000 km² block called B15, which detached from the Ross ice shelf in 2000.
One of his last remaining pieces, now “only” 200 km², is halfway to the South Sandwich Islands in the Atlantic.
Structures of this size need to be constantly monitored because they pose a risk to navigation. Satellite imagery (above and below) is one way to do this.
While keeping an eye on the A68, scientists also monitor two future icebergs about to form.
One is almost breaking free from the Pine Island glacier in western Antarctica. This one will have a little more than 300 km² when it frees itself. The block is already full of cracks.
“The expectation is that the new iceberg will break into many pieces after it has come loose,” says Luckman.
The second is a large iceberg forming in eastern Antarctica, on the edge of the Brunt ice shelf.
This should be about 1,500 km² – about the size of the city of São Paulo.
He drew much attention because a British research station in Antarctica (the Halley base) had to be moved in order not to be affected by the cracks that are forming on the ice shelf.
The iceberg will come loose when a large crack, Crack 1, finally widens to cut a section of the ice completely.
Exactly when it will happen, nobody knows. “The fissure is widening, but at a slow pace,” says Luckman.