An iceberg measuring 1,550 square kilometers – approximately the size of the city of London – and 150 meters thick broke off from the Brunt Ice Shelf in Antarctica on January 22, according to the British Antarctic Survey ( BAS). Despite the spectacular nature of the event, scientists had known for years that this would occur and did not directly relate it to climate change.
A decade ago, researchers at the BAS Halley research station, where glaciologists monitor the behavior of the Brunt Ice Shelf, discovered significant cracks in this icy surface, and in the last two years there have been two major breaks. In fact, in 2017, BAS Halley was moved to a safer location in case of a possible ice breakup. After Sunday’s split, experts say that both the station and the 21 people who currently work there are safe.
The new iceberg is called A-81 and Andrew Shepherd, director of the NERC Center for Polar Observation and Modeling, and principal scientific advisor to the CryoSat satellite mission of the European Space Agency (ESA), clarifies the main doubts regarding its breakup and future trajectory.
– What caused the detachment?
– It is part of the natural cycle. Glaciers move toward the ocean, and icebergs eventually break off when the floating section becomes too fragile.
– Although it has not had a great impact on this iceberg, how is climate change affecting the Antarctic ice?
– Climate change causes glaciers to flow faster, which accelerates the rate at which icebergs calve. Additionally, it can cause more storms and faster melting, increasing the chance of breakage.
– What will happen now with all this ice?
– The ice was already afloat, so it does not pose a threat to sea level rise. Now this iceberg will begin its journey around the Weddell Sea, as it is moved by the ocean current.
– Does it represent any threat?
– It currently poses no risk but will eventually end up crossing the Drake Passage where it can be a danger to ships. Even so, it may take more than a year until that happens.
– What consequences does iceberg calving have on a geological level?
Icebergs carry rocks from Antarctica and spread them across the seafloor as they melt. We have learned a lot about past climate changes by studying them, as it helps us figure out how big the ice sheet was in the past.
Other previous landslides
The new iceberg A-81 is around 1,550 square kilometers, that is, five times the size of Malta. By comparison, iceberg A-68, which broke off from the Larsen-C ice shelf in July 2017, was 5,800 km2. For its part, A-74 had 1,270 km2 when it broke off from the Brunt Ice Shelf in February 2021; while A-76 had 4,320 km2 when it broke off, in May 2021, from the Ronne ice shelf.
The name of the icebergs is composed from the Antarctic quadrant (division of Antarctica into four parts taking as reference the meridians of 0°, 180°, 90° East and 90° West) in which they were originally sighted, to which is added a sequential number. Thus, quadrant A is 0-90W; the B, 90W-180; the C, 180-90E; and D, 90E-0.
If the iceberg subsequently breaks up, each fraction adds a sequential letter to its name. For example, the new iceberg is called A-81 and has a northern split identified as A-81A.