Concern over Antarctic ice melt has gone up in recent months following events such as the collapse of the Larsen C ice shelf. And with global warming continuing unabated, one meteorologist believes that an “ice apocalypse” might take place if two key glaciers in Antarctica eventually collapse as world temperatures continue to rise.
In a feature article published earlier this week on Grist, meteorologist Eric Holthaus wrote about Antarctica’s Pine Island and Thwaites glaciers, noting how these masses of ice have “marched steadily for millennia” toward the Amundsen Sea. Both glaciers were described as a plug of sorts, being capable of holding back up to 11 feet of possible sea-level rise should they melt, an amount that could be enough to submerge all of our planet’s coastal cities. While no one knows when these glaciers will melt, Holthaus said that there is a very good chance that this will happen, and that the more important question is when such events will take place.
“Finding out how fast these glaciers will collapse is one of the most important scientific questions in the world today.”
Due to a phenomenon called “marine ice-cliff instability,” the two Pine Island Bay glaciers in question had most likely collapsed about 11,000 years ago, kickstarting Earth’s last Ice Age. According to Holthaus, global temperatures in those times were roughly the same as they are today, and with marine ice-cliff instability previously cited as a potential “feedback loop” that could lead to the West Antarctic ice sheet melting and disintegrating much sooner than originally forecasted, a “global catastrophe” might be forthcoming if both Pine Island and Thwaites glaciers collapse.
As noted by National Geographic, the ice melt in Pine Island has been especially dramatic, with its ice shelf losing 150 feet between 1994 and 2012. Currently, Pine Island Ice Shelf is approximately 1,300 feet thick in most of its surrounding area. That same report also described Thwaites Glacier as being “more worrisome,” and capable of destabilizing a huge chunk of the West Antarctic Ice Sheet, should it collapse.
Differentiating the two kinds of ice melt that happen in the polar regions, Holthaus wrote that the floating ice that makes up ice shelves does not have much of an impact on sea levels. But land-based ice falling into the sea is “much more troublesome,” as it increases the volume of water and consequently raises sea levels.
With global warming speeding up the process of Antarctic ice melt, Holthaus expects that the collapse of the Pine Island and Thwaites glaciers could happen in just 20 to 50 years, leaving mankind with little time to make the necessary changes.
“A wholesale collapse of Pine Island and Thwaites would set off a catastrophe. Giant icebergs would stream away from Antarctica like a parade of frozen soldiers. All over the world, high tides would creep higher, slowly burying every shoreline on the planet, flooding coastal cities and creating hundreds of millions of climate refugees.”
Citing a 2016 study from climatologists Rob DeConto and David Pollard, Holthaus also explained the possible consequences of sea-level rise in different parts of the world, starting with a three-foot increase that could result in increased flooding in New Orleans, Miami, New York, and other coastal cities in the U.S. He stressed that this is the most optimistic scenario for many scientists concerned about Antarctic ice melt and other similar climate change-driven events. A six-foot sea-level rise, on the other hand, could displace up to 12 million Americans, and potentially wipe out Asian cities like Shanghai, Mumbai, and Ho Chi Minh City. According to DeConto and Pollard’s study, which is detailed in the journal Nature, this is the most likely sea-level rise scenario at the end of the century.
As for the worst-case scenario of an 11-foot rise, Holthaus warned that “hundreds of millions of people” could be submerged underwater, with South Florida “largely inhabitable” and New York and New Jersey besieged by twice-a-month floods similar to those that occurred in the wake of Hurricane Sandy.
Commenting on DeConto and Pollard’s study, University of Michigan ice sheet scientist Jeremy Bassis admitted that it’s not sure if or when marine ice-cliff instability and its effects on Antarctic ice melt would lead to catastrophic sea-level rise. He added, however, that such an event is now “within the realm of possibility”
Despite all the doom-and-gloom scenarios predicted by experts, Holthaus’ Grist feature also cited some scientists who believe that more research is needed before concluding that Pine Island, Thwaites, and other glaciers may collapse and melt several decades from now. According to National Snow and Ice Data Center lead scientist Ted Scambos, both glaciers might not collapse at the same time, but if a rapid collapse happens, it could result in a “pile of icebergs” forming a temporary ice shelf and slowing down Antarctica’s ice melt for the meantime.
With the stakes surrounding the potential collapse of the Thwaites and Pine Island glaciers higher than ever, Holthaus concluded his Grist feature by offering some hope for the future, provided that the world makes a “fast transition” away from the use of fossil fuels. He believes that if this is done within the next few decades, catastrophic sea-level rise could be averted “for centuries.”
[Featured Image by Mario Tama/Getty Images]