ANTARCTIC PENINSULA — The Bellingshausen Sea had approximately 650,000 square kilometers less sea ice in June compared to the average from 1991 to 2020. Satellite observations indicate the Bellingshausen Sea is almost entirely ice-free for the winter season.

Sea ice extent in the region has been low for the third time in four years. Dr. Will Hobbs, an Antarctic sea ice expert, said, "It is remarkable that we are in June and there is no sea ice there," and stated that the sea ice loss is likely linked to ocean changes. He added, "I don’t think we will see sea ice there any more. It’s done," noting scientists are investigating whether global heating is a contributing factor.

Temperatures on the Antarctic Peninsula increased over several days in June. Argentina's Servicio Meteorológico Nacional reported a high temperature event at the Esperanza base on the Antarctic Peninsula, which peaked on June 5 and June 6. Temperatures of 15.4C and 13.4C were recorded at the Esperanza base on these dates, respectively, while the average daily maximum for June at that location is -6.2C. The previous June temperature record at the Esperanza base was 13.3C, set on June 12, 1998.

Hobbs stated that it is reasonable to suggest a recent Antarctic heatwave was intensified by the lack of sea ice. He noted that exact calculations have not been completed. Sea ice typically cools warmer airflow entering the Antarctic region from the north.

The region is important for krill, which typically hide under winter sea ice to graze on algae while avoiding predators. Dr. Peter Fretwell, a scientist, said, "The current loss of sea ice in the region is a serious problem for penguins, especially emperors." Fretwell stated that Adelie penguin populations are declining and crabeater seals are migrating in summer to find stable ice. He said, "Sea ice is forming too late and breaking up too early. It leads to reduced breeding success and longer trips to moulting grounds."

Dr. Phil Reid, who monitors Antarctic conditions at Australia's Bureau of Meteorology, stated that prolonged absence of protective sea ice could cause floating ice shelves to break up faster. He added that this could accelerate glacier ice loss and contribute to sea level rise. The Pine Island and Thwaites glaciers, located west of the Bellingshausen Sea, are major contributors to continental ice loss and sea level rise.