Abrupt climate change-driven shifts in Antarctica’s climate could cause irreversible changes around the world and lead to “catastrophic consequences for generations,” according to a new state-of-knowledge study published in the journal Nature, that found that accelerating shifts across the southern continent both drive, and are driven by, global warming.
“The potential for abrupt changes is far less understood in the Antarctic compared with the Arctic, but evidence is emerging for rapid, interacting and sometimes self-perpetuating changes in the Antarctic environment,” the paper, titled “Emerging evidence of abrupt changes in the Antarctic environment”, stated.
As an examination of the evidence of abrupt change in sea ice, ocean currents, the continent’s ice sheet, ice shelves and marine life, and how all of these factors interact, the study warned that “a marked slowdown in Antarctic Overturning Circulation [AOC] is expected to intensify this century and may be faster than the anticipated Atlantic Meridional Overturning Circulation [AMOC] slowdown”; a slowing or outright stoppage of the AMOC is already a long-running concern that could result in major climatic shifts in Europe.
The study suggests that keeping global temperatures to within 1.5C (2.7F) of the pre-industrial norm “will be imperative” to prevent the wide-reaching effects that an abrupt shift in the Antarctic and Southern Ocean would bring.
Already, the combined melt of glacial ice from Antarctica and Greenland over the past two decades, estimated to be in excess of a trillion tons, has contributed to at least a half-inch of sea level rise.
And on the oceans, the roughly 120-kilometer (75-mile) retreat of reflective surface ice has decreased the Earth’s albedo over that time, creating a feedback loop that causes more sunlight to be absorbed by the oceans, rather than being reflected back into space.
“Antarctica is showing worrying signs of rapid change across its ice, ocean and ecosystems,” study lead Nerilie Abram, a professor at Australian National University, said in a statement. “Some of these abrupt changes will be difficult to stop.”
The study also reported on the impacts that these sea ice changes are already having on Antarctica’s wildlife; as an example, for the last two years whole colonies of emperor penguin chicks were drowned or froze to death when the sea ice gave way before the chicks had a chance to mature, in what the authors describe as “colony-scale breeding failure events”; if this trend continues it could lead to the “potential for extinction of emperor penguins by 2100.”
But as alarming as that situation is, Abram warned that “unstoppable collapse of the West Antarctic Ice Sheet is one of the most concerning global tipping points,” itself estimated to be capable of raising global sea levels by at least three meters (9.8 feet), a situation that would inundate shorelines that are currently inhabited by hundreds of millions of people.
“The evidence points to this being triggered at global warming well below 2°C,” Abram continued. He stressed that the only way to mitigate these effects will be to severely limit greenhouse gas emissions.
“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 warned.