“Almost mind-blowing.” That’s how Walter Meier of the NSIDC describes the records Antarctica has set this year. By mid-September, the sea ice around the southern pole should be reaching its maximum extent. So far, however, the seventh continent is missing 1.5 million sq km of sea ice compared with the average for this time of year, a number well below any previous record. To put this in perspective, an area the size of Mongolia has effectively failed to freeze.  

Antarctica’s vast size means that it is critical for the temperature regulation of the entire planet. The white snow and ice reflect the sunlight back into space, and the ice cools the water beneath it. It is, thus, like a giant refrigerator for the planet. Its size has also meant that, for many years, Antarctica was assumed to have some natural resistance to melting. Indeed, until 2016, the continent’s winter sea ice had been steadily gaining ice mass.  

Three of the past seven Antarctic summers have seen record-breaking minima. In March 2022, when ice should have been refreezing, eastern Antarctica was pummelled by a heatwave that drove temperatures 40C above normal. Rather than being the planet’s largest refrigerator, a melting Antarctica could become a radiator, as it could absorb heat through exposed ocean rather than repel it.  

Reflecting on the heatwave of March 2022, Professor Martin Siegert of the University of Exeter emphasises the assumed immunity of the ice continent: “When I started studying the Antarctic 30 years ago, we never thought extreme weather events could happen there.” 

While the relative lack of data makes it hard to know exactly what is happening with Antarctica long-term, Professor Anna Hogg at the University of Leeds says that the current trends are highlighting that the worst-case scenario for Antarctica might be ravelling. Professor Siegert asks whether [we are] “awakening this giant of Antarctica.” If so, it would be “an absolute disaster for the world.”  

Land ice from Antarctica has contributed 7.2mm of sea level rise since 1990, placing it behind Greenland in terms of global contribution. However, even a small increase in melt would escalate storm surges and saltwater intrusion, and thus would be devasting for millions of people around the world, especially those in coastal and low-lying communities.

Image source: Amanderson2, CC BY 2.0, via Wikimedia Commons