A new study suggests we may lose Antarctica for good, even if we keep the global rise in temperature below the Paris Climate Agreement level. According to the study, published in Nature, the melting of Antarctica’s glaciers and the subsequent increase in sea level might not be reversible even if governments decide to take the climate crisis seriously.
The melting of the ice sheets in the most optimistic of scenarios will threaten species, people, and cities across the world. And that’s assuming we achieve the Paris Climate goal of an increase less than 2°C (3.6°F) above pre-industrial levels.
“Because of its sheer magnitude, Antarctica's potential for sea-level contribution is enormous,” corresponding author Ricarda Winkelmann, from the Potsdam Institute for Climate Impact Research (PIK), said in a statement. “We find that already at 2 degrees of warming, melting and the accelerated ice flow into the ocean will, eventually, entail 2.5 meters (8 feet) of global sea level rise just from Antarctica alone. At 4 degrees, it will be 6.5 meters (21 feet) and at 6 degrees almost 12 meters (39 feet) if these temperature levels would be sustained long enough."
Antarctica holds half of the fresh water on our planet. Its vast ice-sheet is nearly 5 kilometers (3 miles) thick in places. This year, record-breaking temperatures have been recorded on the continent and the melting of its glaciers have dramatically accelerated.
To understand how the continent will evolve, the team used a supercomputer simulation since a single processor would take 1 million hours (about 114 years) to run the scenario, highlighting just how many factors are in play when it comes to the melting. Worryingly, the evidence suggests the changes we are causing are irreversible due to self-enforcing mechanisms.
"In West Antarctica for instance, the main driver of ice loss is warm ocean water leading to higher melting underneath the ice shelves, which in turn can destabilize the grounded ice sheet. That makes glaciers the size of Florida slide into the ocean," said co-author Torsten Albrecht from PIK. "Once temperatures cross the threshold of six degrees above pre-industrial levels, effects from the ice surface become more dominant: As the gigantic mountains of ice slowly sink to lower heights where the air is warmer, this leads to more melt at the ice surface – just as we observe in Greenland."
“Antarctica is basically our ultimate heritage from an earlier time in Earth's history. It's been around for roughly 34 million years,” added Anders Levermann, co-author and researcher at PIK and Columbia University. “Now our simulations show that once it's melted, it does not regrow to its initial state even if temperatures eventually sank again. Indeed, temperatures would have to go back to pre-industrial levels to allow its full recovery – a highly unlikely scenario. In other words: What we lose of Antarctica now, is lost forever.”