Scientists warn that abrupt and possibly irreversible climate change-driven changes in Antarctica could cause the world's oceans to rise by meters and have "catastrophic consequences for generations."
According to a study published in Nature, a state-of-knowledge review conducted by a number of leading experts revealed accelerating changes throughout the region that are frequently both a cause and an effect of global warming.
Lead author and Australian National University professor Nerilie Abram told AFP, "Antarctica is showing worrying signs of rapid change across its ice, ocean and ecosystems," adding, "Some of these abrupt changes will be difficult to stop."
According to Abram, changes in various aspects of Antarctica's climate system reinforce one another and have sped up global warming.
Sea ice, regional ocean currents, the continent's ice sheet and ice shelves, and marine life were all examined for indications of sudden change, or "regime shifts." It also looked at their interactions.
When floating sea ice melts, the sea level does not rise. However, as it retreats, deep blue water absorbs the same amount of the Sun's energy as white surfaces that reflect nearly all of it back into space.
Oceans absorb 90% of the heat produced by human-caused global warming.
Retreating Sea Ice
Over the past ten years, Antarctic Sea ice cover has drastically decreased after rising marginally during the first 35 years of satellite data availability.
Sea ice has receded from the continent's coastline by an average of 120 kilometers since 2014. In the last ten years, that contraction has occurred roughly three times as quickly as the Arctic Sea ice decline over the previous fifty years.
According to the study, based on current trends, Antarctica may effectively become ice-free in the summer before the Arctic due to the "overwhelming evidence of a regime shift in sea ice."
This could lead to the extinction of some marine species and accelerate warming in the area and beyond.
For instance, helpless emperor penguin chicks have drowned or frozen to death at several breeding grounds over the past two years when sea ice gave way earlier than usual under their tiny feet.
According to previous research, all but one of the five sites in the Bellingshausen Sea region that were monitored in 2023 saw a 100% loss of chicks.
Ice sheets and the ice shelves they are attached to are on or supported by land, in contrast to sea ice.
Heading Towards Point of No Return?
The melting of the entire Antarctic ice sheet would raise the world's oceans by an almost unthinkable 58 meters, requiring a five-degree Celsius increase in global temperature over pre-industrial levels.
According to the study, however, global warming to date—on average, around 1.3C—is rapidly approaching a threshold that would cause a portion of the ice sheet to produce at least three meters of sea level rise, flooding coastal areas that are currently inhabited by hundreds of millions of people.
"Unstoppable collapse of the West Antarctic Ice Sheet is one of the most concerning global tipping points," said Abram.
She added, "The evidence points to this being triggered at global warming well below 2C."
The Antarctic Overturning Circulation, a network of ocean currents that disperse heat and nutrients both locally and internationally, could also collapse.
Evidence from the previous interglacial period, which occurred between two ice ages before our own, 125,000 years ago, suggests that the system abruptly stagnated under circumstances similar to those observed today, and that a "rapid and substantial slowdown" of the currents has already started.
According to the study, "this would lead to widespread climate and ecosystem impacts," which could include anything from a worsening of global warming to a reduction in the ocean's ability to absorb CO2.
In the end, reducing the amount of planet-warming gases released into the atmosphere is the only way to slow down the interlocking changes.
"The greenhouse gas emission decisions that we make over the coming decade or two will lock in how much ice we will lose and how quickly it will be lost," Abram concluded.
