| Antarctica is almost twice the size of Australia – about 40% bigger than Europe – and it holds enough ice that, if it were to disintegrate, it would reshape the planet’s coastlines, flood many of the world’s biggest cities and put entire countries underwater. So what happens down there matters a lot. And while 2023 will very (very) likely be the hottest on record globally, the year may also turn out to be the one where “everyone realises Antarctica is going in a direction that nobody wants to see happen”, as one oceanographer said to me this week. I’ve been told several times by different scientists this year that until recently, there was a general view that Antarctica might be big enough and cold enough to be the planet’s last holdout from the climate crisis. But the events of this year have caused many to doubt that assumption. In February, the sea ice surrounding the continent hit its lowest levels on record – easily beating the previous low that was set only a year earlier. As the Antarctic winter set in, the recovery of the sea ice stalled and for the first time on the satellite record going back 44 years, the September maximum failed to get above 17m sq kilometres. Losing sea ice means a loss of the reflective ‘albedo effect’ at the planet’s surface, exposing more ocean to warming that can then make it harder for ice to grow back. A feedback loop. Antarctica’s ecology is also acutely tied to the sea ice and the algae that lives under it. The knock-on effects could be profound for the continent’s wildlife. Thousands of emperor penguin chicks in West Antarctica likely died last year because the sea ice under their colonies collapsed. Also this year, we’ve seen research suggesting the continent – chronically short of long-term observations – is warming at double the rate suggested by models used in UN climate reports. A deep Antarctic ocean current that influences marine environments and the climate around the globe is already slowing down because of the meltwater – a slow-down that could accelerate in coming decades. There are clues from the past, too, that the break-up of ice sheets such as Antarctica’s could happen far quicker than expected and be sporadic and violent, rather than smooth and predictable. Analysis of octopus DNA suggests the last time temperatures were as high as they are now, the ice sheet in West Antarctica did collapse. In the wake of all this, the Australian government has come under harsh criticism for cutting research projects in and around Antarctica after a budget overspend. Separately, just days ago an international meeting failed again to create marine protected areas of about 4m sq kilometres off the continent, with my colleague Adam Morton reporting the Russian delegation – which arrived late to the meeting in Tasmania – blocked the consensus needed to approve it. Antarctica’s waters look to be coming under pressure from global heating, so conservationists argue protecting its wildlife now from impacts like fishing will give ecosystems the resilience they are so clearly going to need. Last week, research found West Antarctica’s ice shelves (floating on the surface, but protecting the ice sheets behind them) were now committed to an accelerated rate of melt this century no matter how “ambitious” cuts to emissions turn out to be. That research paper, in the journal Nature Climate Change, came with this remarkable observation from the scientists: the chance to keep the West Antarctic Ice Sheet in its present-day state “has probably passed, and policymakers should be prepared for several metres of sea-level rise over the coming centuries”. “Limiting the societal and economic costs of sea-level rise will require a combination of mitigation, adaptation and luck,” the scientists wrote. “Luck” is not a word you read that often in climate change research. But it’s up to governments and voters everywhere to decide how much of a gamble we’re willing to take. Because unlike Las Vegas, what happens in Antarctica does not stay in Antarctica. Read more on Antarctica: | 