"First, one has to wonder if perhaps we have already passed the West Antarctic collapse tipping point," the expert added on social media. "Second, it begs the question, are other climate model projections underestimating the speed of climate breakdown?"
Polar amplification, a phenomenon that causes higher temperatures near the poles, is well established in the Arctic, with a study published last yearshowing that the northern region is warming nearly four times faster than the global average. However, it has been less clearly identified across Antarctica, where scientists must contend with limited available temperature records and natural climate variability.
Due to the lack of Antarctic weather stations covering more than the past six decades, the four researchers behind the new study—who come from various European institutions—analyzed 78 ice cores to determine temperature variability over 1,000 years across seven regions.
The team found "direct evidence of Antarctic polar amplification at regional and continental scales," which major climate models don't show. The study states that "failing to consider the feedback loops causing polar amplification could lead to an underestimation of the magnitude of anthropogenic warming and its consequences in Antarctica."
Lead author Mathieu Casado, of the Laboratoire des Science du Climat et de l'Environnement in France, toldThe Guardian that "it is extremely concerning to see such significant warming in Antarctica, beyond natural variability."
Kyle Clem, a scientist at Victoria University of Wellington in New Zealand who was not involved with the new research but has studied record high temperatures at one South Pole weather station, told the newspaper that "the implications of this study are of particular importance for considering future changes in Antarctic sea ice, terrestrial and marine ecosystems, and potentially even sea-level rise."
"As far as sea-level rise, ocean warming is already melting protective ice shelves in West Antarctica and causing the West Antarctic ice sheet to retreat," Clem said. He also highlighted the potential impact on coastal ice shelves that protect glaciers, explaining that "this has already been seen on the Antarctic peninsula in recent decades, and it could become a more widespread occurrence around Antarctica sooner than anticipated in a more strongly warming Antarctic climate."
The research from Casado's team was published the same day as a study about the West Antarctic ice sheet published in The Cryosphere.
"With more and more ice being lost in Antarctica over the last years, concerns have been raised whether a tipping point has already been crossed and an irreversible, long-term collapse of the West Antarctic ice sheet has already been initiated," noted lead author Ronja Reese of the Potsdam Institute for Climate Impact Research in Germany and England's Northumbria University.
"The results of our studies deliver two messages: First, while a number of glaciers in Antarctica are retreating at the moment, we find no indication of irreversible, self-reinforcing retreat yet, which is reassuring," Reese said. "However, our calculations also clearly indicate that an onset of an irreversible retreat of the ice sheet in West Antarctica is possible if the current state of the climate is sustained."
The new studies follow findings throughout this year that have elevated fears about the impact of human-caused global heating on Antarctica—from researchers revealing in February that Antarctic sea ice coverage hit its lowest January level ever recorded, to a May study that showed a 30% slowdown in vital deep water currents around the continent.
Research from last month warned it is "virtually certain that future Antarctic extreme events will be more pronounced than those observed to date" as humanity continues to burn fossil fuels, the key driver of the climate emergency. Another August study found that when Antarctic sea ice melted last year, it likely killed over 9,000 emperor penguin chicks.
Both Reese and Casado's studies also cap off a week of alarming global data about the climate emergency. International researchers confirmed that greenhouse gas concentrations, global sea level, and ocean heat content broke records last year. Scientists also announced that this summer of deadly heat is the hottest on record.
