World's largest iceberg is falling apart! Huge TRILLION tonne megaberg that was once more than twice...

At the start of this year, it was more than twice the size of Greater London. 

And as we enter September, the world's largest iceberg, known as A23a, is sadly nearing its end.

Ranked among the oldest and largest megabergs ever recorded, A23a has crumbled apart in warmer waters and could disappear within weeks, scientists say.

Often compared in shape to a tooth, the colossal iceberg has been travelling north in the South Atlantic Ocean for months. 

Now exposed to increasingly warmer waters and buffeted by huge waves, the former 'king of the seas' has rapidly disintegrated. 

Mr Andrew Meijers, a physical oceanographer at the British Antarctic Survey (BAS), said A23a has been 'breaking up fairly dramatically' as it drifts further north. 

'Oh I'd say it's very much on its way out... it's basically rotting underneath,' Meijers told AFP.

'[Recently] the water is way too warm for it to maintain. It's constantly melting.' 

Going back to early this year, the megaberg weighed around one trillion tonnes – about 100 million times as heavy as the Eiffel Tower in Paris. 

At its peak, A23a was around 1,540 sq miles in area – more than twice the size of Greater London (607 sq miles) – and a whopping 1,312 feet thick.  

Now, it is 683 square miles and 37 miles at its widest point, according to AFP analysis of satellite images, making it less than half its original size. 

In recent weeks, hefty chunks measuring about 150 sq miles have broken off, while smaller 'chips', many still large enough to threaten ships, litter the sea around it. 

Much like coastal erosion of land, waves are crashing against the berg to make gaps that grow steadily bigger until the top collapses, leaving little 'stacks' which then form smaller 'stumps'. 

As it keeps drifting north, carried by ocean currents, surrounding waters become warmer and the berg will soon melt away completely.

'I expect that to continue in the coming weeks, and expect it won't be really identifiable within a few weeks,' said Mr Meijers. 

Scientists have been 'surprised' how long the iceberg had kept together, according to Meijers.

How do icebergs form? 

An iceberg is a piece of freshwater ice that has detached from a glacier and is floating in the ocean.

Icebergs form when pieces of ice break off the end of an ice shelf or a glacier that flows into a body of water.

 This is called 'calving' and it's a natural process that is responsible for ice loss at the edges of glaciers and ice sheets.

Source: antarcticglaciers.org

He added: 'Most icebergs don't make it this far. This one's really big so it has lasted longer and gone further than others.'

But ultimately, icebergs are 'doomed' once they leave the freezing protection of Antarctica – and it's just a matter of time before they vanish. 

A23a is the surviving largest fragment of an iceberg that broke free of the Antarctic's Filchner Ice Shelf in August 1986. 

It had only moved a couple of hundred miles when it became stuck, or 'grounded' to the ocean floor – and ended up becoming stationary for the next 30 years. 

Icebergs 'ground' on the ocean floor when their keel (the bit below the water's surface) is deeper than the water's depth. 

A23a finally broke free in 2020 and started moving northwards, although its journey has been occasionally delayed by ocean forces that kept it spinning on the spot.

This monster block of freshwater was being whisked along by the world's most powerful ocean 'jet stream' – the Antarctic Circumpolar Current. 

Around March, it ran aground in shallow waters off distant South Georgia island, raising fears it could hit breeding and feeding grounds of adult penguins and their young. 

Fortunately, A23a dislodged in late May, swung around the island, and carried on its journey northwards. 

However, the grounding and 'enormous release of cold freshwater' are likely to have had a major impact on organisms on the seabed and in the surrounding water, a spokesperson at BAS told the Daily Mail. 

In recent weeks, the berg has picked up speed, sometimes traveling up to 12 miles (20km) in a single day – about the distance between Camden and Croydon. 

Mr Meijers, who encountered the iceberg in late 2023 and has tracked it with satellites ever since, called A23a a 'huge Game of Thrones style wall of ice'. 

'With some waves breaking against it and if you get a bit of sunshine coming through, it´s really dramatic,' he said. 

Iceberg 'calving' – the breaking off of chunks from the edge – is a natural process, often caused by the formation of crevasses. 

But scientists say the rate at which bergs are being lost from Antarctica is increasing, probably because of human induced climate change.

What are icebergs and why are they important?

Icebergs are pieces of freshwater ice more than 50 feet long that have broken off a glacier or an ice shelf and are floating freely in open water. 

Icebergs that break off from an already floating ice shelf do not displace ocean water when they melt - just as melting ice cubes do not raise the liquid level in a glass. 

Some icebergs contain substantial amounts of iron-rich sediment, known as 'dirty ice'. 

'These icebergs fertilise the ocean by supplying important nutrients to marine organisms such as phytoplankton,' said Lorna Linch, lecturer in physical geography at the University of Brighton.  

Icebergs can also pose danger to ships sailing in the polar regions - as demonstrated in April 1912, when an iceberg led to the sinking of RMS Titanic in the North Atlantic Ocean. 

Icebergs may reach a height of more than 300 feet above the sea surface and have mass ranging from about 100,000 tonnes up to more than 10 million tonnes. 

Icebergs or pieces of floating ice smaller than 16 feet above the sea surface are classified as 'bergy bits', while those smaller than 3 feet are 'growlers'. 

Read more

• Could the massive A23a iceberg's dramatic fragmentation signal its imminent demise or a chilling reshaping of our oceans?
• Could climate change spell disaster for Antarctic wildlife? The perilous journey of icebergs like A-84 could decimate precious ecosystems!
• Is climate change accelerating the demise of megabergs like the towering A23a in the icy realms of Antarctica?
• Can the colossal A23a iceberg's unshackling unleash ecological wonders in the Southern Ocean?
• Is the mighty iceberg A23a on track to wreak maritime chaos after freeing itself from a mysterious ocean trap?