The world’s biggest iceberg, the catchily-named A23a, has been revealed to have a mass of nearly one trillion tonnes.
Satellite measurements from the European Space Agency’s CryoSat-2 mission found that the ice block has an average thickness of 280 metres – for scale, the UK’s tallest building, the Shard in London, is 310 metres tall.
In addition, it is known that A23a has an area of 1,500 square miles, giving a volume of about 1,100 cubic kilometres and a volume of just under one trillion tonnes, which is mind-bogglingly big.
A23a broke away from the Antarctic coast way back in 1986. While it was grounded on mud banks for many years, it has been drifting slowly now for some time, but it is now at a critical point where it will soon drift beyond the continent. This is significant as it means it is closer to warmer waters and therefore could melt at a faster rate.
CryoSat2 uses a radar altimeter to sense how much of A23a was above the waterline. Combined with data on the density of ice, scientists can work out how much of the iceberg is below the water.
This is also significant as they can work out where an iceberg may ground, using maps of the sea floor and data on the deepness of the water.
