Recently a slab of ice along the rift system broke off the Amery ice shelf. Amery is the third largest ice shelf in Antarctica and is a key drainage channel for the east of the continent. Not since the early 1960s has Amery calved a bigger iceberg. That was a whopping 9,000 km2 in area.
The current piece to break off is not bigger than its still wobbling neighbor known as D28. It is a giant iceberg which is roughly the size of urban area of Sydney, Australia, covering 1,635 km and reaching about 209 meters deep. Altogether, it amounts to 312 billion tons of ice, the largest iceberg produced by the Amery ice shelf in more than half a century.
The shelf is essentially the floating extension of a number of glaciers that flow off the land into the sea. Losing bergs to the ocean is how these ice streams maintain equilibrium, balancing the input of snow upstream.
Scientists say there is nothing to worry about
While all this sounds alarming given the current state of our plant, some scientists say it is a natural inevitability phenomenon known as calving. The ice shelves slough off the edges to make room for new flows of snow and ice. So, scientists knew this calving event was coming.
What’s interesting is that much attention in the area had actually been focused just to the east of the section that’s now broken away. In addition, this is a segment of Amery that has affectionately become known as ‘Loose Tooth’ because of its resemblance in satellite images to the dentition of a small child.
Both ice areas had shared the same rift system. It’s an imperative way for ice sheets around the world to balance their masses, but each one experiences a different rate of calving that can vary across seasons and take decades or longer to complete. All these variables make it challenging to predict when an iceberg will calve, and in this case, researchers were off on both the timeline and the location.
According to a renowned scientist Fricker, a rift at the front of the ice shelf in the early 2000s was noticed and it was predicted that a large iceberg would break off between 2010 and 2016. In his words, “I am excited to see this calving event after all these years. We knew it would happen eventually, but just to keep us all on our toes, it is not exactly where we expected it to be but this has nothing to do with climate change.”
The last time the Amery ice shelf produced an iceberg like this, it was in the year 1963. The resulting iceberg back then was even bigger than what we are seeing today. Also, this particular ice shelf is thought to experience one major calving event every six to seven decades. As a result, many scientists like Fricker, do not think this event is linked to climate change. This is just a natural phenomenon where ice shelf’s make room for new flows of snow and ice.