‘It’s depressing’: A France-sized area of Antarctica’s winter sea ice is missing as temperatures soar 20°C above average |

A vast area of Antarctica that should be covered in winter sea ice is instead lying largely exposed to the ocean, alarming scientists and raising fresh concerns about the future of the frozen continent. Satellite observations show that roughly 650,000 square kilometres of sea ice, an area comparable to the size of France, has failed to form in the Bellingshausen Sea off West Antarctica. The unusual ice loss comes as parts of Antarctica experienced a remarkable winter heatwave, with temperatures climbing more than 20°C above average. Researchers say the event could have consequences for penguins, marine ecosystems and even future sea-level rise.

Antarctica is supposed to be freezing right now

For most people, Antarctica is synonymous with ice. What makes this latest development so concerning is that it is happening during the Antarctic winter.Unlike the Arctic, where sea ice reaches its maximum extent around March, Antarctica’s sea ice expands through the southern winter, typically growing rapidly from March until September. By June, the Bellingshausen Sea, located west of the Antarctic Peninsula, would normally be covered by a broad blanket of sea ice.Instead, satellite imagery shows the region is almost entirely ice-free.Scientists estimate the area is missing approximately 650,000 square kilometres of sea ice compared with the average observed between 1991 and 2020. To put that into perspective, France covers about 551,000 square kilometres.Dr Will Hobbs, an Antarctic sea ice expert at the University of Tasmania and the Australian Antarctic Program Partnership, described the situation bluntly.“I’m concerned. It’s depressing.”He added:“It is remarkable that we are in June and there is no sea ice there.”

Why scientists are particularly worried this time

Sea ice naturally varies from year to year, but researchers say this is not an isolated event.According to Hobbs, this is the third time in four years that sea ice in the Bellingshausen Sea has been exceptionally low. Scientists have become increasingly concerned because repeated low-ice years suggest something more significant than normal fluctuations may be taking place.Perhaps the most striking statement came when Hobbs suggested that the region may be entering a new normal.“I don’t think we will see sea ice there any more. It’s done.”While other scientists caution that more research is needed before reaching such a conclusion, the statement highlights growing concern among polar researchers that long-term changes may be underway in West Antarctica.Scientists are now investigating whether shifts in ocean circulation, warmer ocean temperatures and human-driven climate change are combining to prevent ice from forming as it once did.

The extraordinary Antarctic heatwave

The missing sea ice coincided with one of the most unusual winter warming events recorded on the Antarctic Peninsula.At Argentina’s Esperanza research station, temperatures reached 15.4°C on 5 June and 13.4°C on 6 June. Those figures are extraordinary for a region where average daytime temperatures in early June are around -6.2°C.In other words, temperatures were more than 20°C above normal.The 15.4°C reading also surpassed the station’s previous June record of 13.3°C, which had stood since 1998.Meteorologists at Argentina’s Servicio Meteorológico Nacional described the event as an “extreme temperature event”, highlighting just how unusual the conditions were for the middle of the Antarctic winter.

Did the missing sea ice make the heatwave worse?

Scientists believe the two events may be connected.Sea ice acts like a giant natural air conditioner. When warmer air moves southward from lower latitudes, the ice helps cool that air before it reaches Antarctica.Without the ice cover, the ocean is exposed directly to the atmosphere. Open water absorbs and stores much more heat than ice, allowing warmer conditions to persist.Dr Hobbs explained that while detailed calculations have not yet been completed, it is reasonable to suspect the lack of sea ice intensified the heatwave. Normally, a large frozen surface would reflect heat and cool incoming air masses. Open water, however, absorbs and releases more heat.Scientists say this creates a feedback cycle. Less sea ice exposes more ocean water, which absorbs more heat. The warmer conditions then make it harder for sea ice to form, further reinforcing the warming trend.

Sea ice is not the same as glaciers

One common misconception is that all Antarctic ice behaves in the same way.Sea ice forms when ocean water freezes. It floats on the surface and grows and shrinks seasonally. Glaciers and ice sheets, by contrast, sit on land and contain enormous amounts of frozen freshwater.Because sea ice is already floating, its melting does not directly raise sea levels. However, that does not mean its disappearance is harmless.Sea ice reflects sunlight back into space, helping keep the region cool. It also protects Antarctic coastlines from powerful ocean waves and provides critical habitat for many species. In addition, it shields vulnerable ice shelves from damage by ocean swells and storms.Without sea ice, Antarctica becomes more exposed to warming and erosion.

The connection to Thwaites and Pine Island glaciers

Scientists are especially concerned because the Bellingshausen Sea lies close to some of Antarctica’s most vulnerable glaciers, including Thwaites Glacier and Pine Island Glacier.Both glaciers are among the largest contributors to Antarctic ice loss and global sea-level rise.Dr Phil Reid of Australia’s Bureau of Meteorology notes that sea ice acts as a protective buffer in front of floating ice shelves attached to these glaciers. When sea ice is absent, ocean waves can more easily reach and damage the ice shelves.If ice shelves weaken or break apart, the glaciers behind them can flow more rapidly into the ocean. Over time, this process contributes directly to rising sea levels around the world.

What does this mean for penguins?

The consequences extend far beyond ice.Sea ice is a critical part of Antarctica’s ecosystem. Beneath the ice grows algae that form the foundation of the Antarctic food web. Tiny shrimp-like creatures known as krill feed on these algae, and many larger animals depend on krill for survival.Emperor penguins, Adélie penguins, crabeater seals, whales and numerous seabirds all rely on healthy sea ice ecosystems either directly or indirectly.Dr Peter Fretwell of the British Antarctic Survey has spent years studying emperor penguin populations and their dependence on stable sea ice.According to Fretwell:“Sea ice is forming too late and breaking up too early.”He warned that changing ice conditions are reducing breeding success and forcing penguins to travel greater distances in search of suitable habitat.

The tragic penguin disaster of 2022

Scientists have already witnessed what happens when sea ice disappears too early.In late 2022, thousands of emperor penguin chicks died after sea ice beneath their colonies broke apart before the young birds had developed waterproof feathers.Researchers described the event as a catastrophic breeding failure. The chicks fell into freezing water before they were physically capable of surviving in the harsh Antarctic environment.The disaster contributed to international conservation authorities upgrading emperor penguins to endangered status earlier this year.The current sea ice deficit raises fears that similar breeding failures could become more common if sea ice continues to decline.

Is Antarctica entering a new era?

For decades, Antarctic sea ice behaved differently from Arctic sea ice.While Arctic sea ice showed a clear long-term decline, Antarctic sea ice remained comparatively stable and even experienced periods of growth. That pattern changed dramatically during the past decade.Since 2016, Antarctica has recorded several record-low sea ice years. Scientists are increasingly debating whether the continent has crossed a threshold into a new period characterised by persistently lower sea ice coverage.Researchers caution that one season alone cannot prove a permanent shift. However, repeated years of exceptionally low sea ice are becoming harder to dismiss as natural fluctuations.The Bellingshausen Sea event is therefore being watched closely because it may offer clues about how Antarctica is responding to a warming world.

What happens next?

Scientists will continue monitoring Antarctic sea ice through September, when it typically reaches its annual maximum extent.The key question is whether the Bellingshausen Sea eventually freezes later this winter or whether the deficit persists for months.Researchers are also examining ocean temperature records, atmospheric circulation patterns, wind changes around Antarctica and long-term climate trends. Their findings could help determine whether this year’s event is a temporary anomaly or evidence of a deeper transformation occurring at Earth’s southernmost continent.A France-sized area of winter sea ice missing from Antarctica is more than a striking statistic. It is a warning sign from one of the planet’s most climate-sensitive regions.The fact that the ice failed to form during winter, rather than melting during summer, is what has captured scientists’ attention. Combined with temperatures soaring more than 20°C above average, the event is raising urgent questions about the future of Antarctic sea ice, the wildlife that depends on it and the stability of the ice sheets that help regulate global sea levels.