On May 20th, 2024, an iceberg spanning 380 square kilometers (~147 mi2) detached from Antarctica’s Brunt Ice Shelf.
This detachment, labeled A-83, marks the third major iceberg calving from this area in the last four years. The sequence began in 2021 with the calving of A-74, followed by a larger iceberg, A-81, in 2023.
This most recent iceberg separation was documented by two Earth Observation satellites—the ESA’s Copernicus Sentinel-1 and NASA’s Landsat 8—which supplied radar and thermal imagery, respectively.
The U.S. National Ice Center, responsible for naming such icebergs, has designated it A-83. This naming follows a system based on the Antarctic quadrant where the iceberg is first identified.
Located in the eastern Weddell Sea, the Brunt Ice Shelf icebergs receive an ‘A’ prefix, while the numbers are issued in sequence. Satellite monitoring of ice shelves is crucial for observing the impacts of climate change on remote areas like Antarctica.
This activity helps scientists observe the structural stability of ice shelves amid evolving ice conditions and rising temperatures in both the atmosphere and oceans.
The formation of A-83 was influenced by weakening ice at the McDonald Ice Rumples and the expansion of the ‘Halloween Crack’ across the shelf.
The Copernicus Sentinel-1 mission utilizes radar imaging to provide year-round imagery, crucial during the Antarctic Night, which spans six months of darkness.
Landsat 8 employs thermal imaging that assists in assessing ice sheet thickness. As depicted, thinner ice shows up warmer, indicating proximity to the water’s temperature, whereas thicker ice is cooler and appears darker. These temperature contrasts aid in pinpointing the calving line.
Thankfully, this iceberg poses no threat to the British Antarctic Survey’s Halley VI Research Station, which remains on the Brunt Ice Shelf but was moved to the safer Caird coast in 2017 due to instability in the outer shelf.
The continuous ice loss in Antarctica signals escalating global temperatures and is an urgent alert. This melting not only contributes to rising sea levels, coastal flooding, and extreme weather conditions but also leads to increased oceanic absorption of solar radiation, further elevating temperatures.
Tracking these polar ice sheets is crucial for developing adaptation and mitigation strategies, as highlighted in the IPCC’s Sixth Assessment Report (AR6).
