Sea ice around Antarctica is at its lowest level since satellites began tracking it in 1979, according to researchers, who say the frozen continent is “suffering” due to the burning of fossil fuels.
Global warming is causing extreme events that were unthinkable 30 years ago, scientists have said.
“I think it's reasonable to assume that with the Antarctic heat event that we've seen, that is the sort of thing that has been expected with global heating because of burning fossil fuels and it has happened,” said Martin Siegert, a glaciologist at the University of Exeter.
“It could be, because we've done a lot of scientific evidence, that it was just one of those one-in-1,000-year events, but that's so unlikely, and I think it's perfectly scientifically reasonable to make the assumption that it is linked to our heating planet.
“Antarctica is suffering as a consequence of burning fossil fuels and there will be more to come.”
Sea ice this year beat the previous minimum record set in 2022, when a winter heatwave in March saw temperatures soar nearly 40°C above the norm in East Antarctica, from about minus 50°C to minus 10°C.
Had that happened in summer, it would have begun melting the surface of the ice sheets, which scientists said they have never seen before.
Because of Antarctica's harsh environment and remote location, there is less data available to unequivocally link events such as these with human-induced climate change, but scientists say they are to be expected on a warming planet.
Together with scientists from across the UK, Chile and South Africa, Mr Siegert has been examining evidence of extreme events in Antarctica and said it is “virtually certain” that their severity will increase unless greenhouse gas emissions are controlled.
Publishing their work in the journal Frontiers in Environmental Science, they identified nearly a dozen ways that human actions are changing the Antarctic, from melting sea and land ice, the collapse of ice shelves, warming oceans and atmosphere, the near-extinction of marine animals and introduction of foreign species such as moss and grass.
Scientists are particularly concerned about what might happen over the next few years as the warming effects of El Nino take hold.
Anna Hogg of the University of Leeds said: “As somebody who watches this happen on a day-to-day basis, I'm finding it really surprising and staggering to see the changes occur at the scale that they are already.”
She said it would take centuries for collapsed ice shelves to recover, if it was even possible.
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These collapses do not directly add to sea level rise as the ice is already floating, but it means ice from the land pours into the sea much faster via glaciers, which is speeding up the rate of sea-level rise.
If all the ice in Antarctica were to melt – although scientists do not believe this will happen anytime soon – it would push up the global sea level by 57 metres.
Extreme events such as ice shelf collapse or heatwaves combine in cascading or multiplying effects that reach across the world but also threaten native species.
The team of scientists are calling for more environmental protection measures to be put in place to help conserve increasingly fragile ecosystems that are becoming more exposed.
Melting ice could result in better access for ships bringing more people for example, who therefore must take care not to bring non-native seeds on their boots.
The UK Foreign Office is looking to give better protection to emperor penguins, which are a “climate-vulnerable” species, said the department's head of polar regions Jane Rumble.
Mr Siegert said: “I think the scientific community has been shocked by this season's lack of sea ice, so much lower than has happened in previous years.
“The enormous Antarctic heatwave that happened last time, the staggering loss of ice shelves, it just wasn't really relevant in 1990.
“So things are changing and they're changing because of burning fossil fuels. And that is going to continue.”