Following the breakup of Iceberg A-81 at the end of January 2023, the Brunt Ice Shelf in Antarctica is moving faster than before. Currently, it moves about 4 meters (13 feet) per day toward the ocean, whereas before the iceberg melted, it averaged 1-2.5 meters (3-8 feet) per day. The observations were submitted to The Cryosphere magazine this week.
The Brant Ice Shelf is one of the most studied ice shelves in the world. Its glacier structure is complex, and the impact of ice avalanche events is often difficult to predict. Researchers believe climate change did not play a significant role in the recent acceleration of the Brant Ice Shelf. The Brunt Ice Shelf accelerated because after Iceberg A-81 melted, the ice shelf lost contact with the seafloor known as the McDonald Ice Fold.
This connection has helped stabilize the ice shelf in the 67 years since it was first occupied and instrumented. Today, ice shelf movement rates are typically measured only on ice shelves fed by particularly fast-flowing outlet glaciers, such as the Thwaites Glacier in West Antarctica.
After the A-81 iceberg melted at the end of January 2023, the Brunt Ice Shelf moved faster than before. Source: British Antarctic Survey
Scientists from the British Antarctic Survey (BAS) are closely monitoring the situation using GPS equipment deployed on the ice and satellite data. The Halley Research Station is located on the most stable part of the Brunt Ice Shelf, 20 kilometers away from the new ice front. Monitoring data is used to help the Halley Research Station formulate operational plans. In 2016, the UK's National Office for Scientific and Industrial Research took the precautionary step of moving the Halley Research Station 23 kilometers inland from the Chasm-1 chasm that ultimately caused the sinking of Iceberg A-81.
Scientists from the British Antarctic Survey (BAS) are closely monitoring the situation using GPS equipment deployed on the ice and satellite data. Source: BASA
Halley is closed during the Antarctic winter and there is currently no staff on the station. The Antarctic Scientific Research Service's operational team is currently planning the regular field expedition season at Halley Station, with a team of 40 people set to fly to the Brant Ice Shelf in November 2023. They will spend the season maintaining power supplies and facilities to keep science experiments running remotely throughout the winter. Their work will continue until the aircraft is recovered in February 2024.
The BAS operations team is currently planning Halley's regular field season, with a team of 40 people due to fly to the Brunt Ice Shelf in November 2023. Source: BAS
BAS glaciologist Professor Dominic Hodgson is part of the scientific team that has been studying the Brant Ice Shelf for more than ten years:
"This is a dynamic situation. We expect the ice shelf to respond to the formation of the A-81 ice sheet. We are monitoring accelerations and conducting further experiments to determine if and when the ice shelf will re-contact the seafloor. This will be demonstrated by a stabilization or decrease in the ice shelf's velocity, which we will be able to record in real time. Our science and operations teams will continue to monitor the ice shelf to ensure its safety and continue scientific research at Halle."