Melting of West Antarctic ice is expected to accelerate significantly in the coming decades, causing sea levels to rise, even if the world meets its commitments to limit global warming, according to a study published Monday.
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British Antarctic Survey researchers behind the new study have warned that humanity has “lost control” over the fate of ice shelves, those gigantic frozen structures that float on the edge of the main ice and play a stabilizing role in restraint the drift and melting of glaciers in the ocean.
Antarctica has already seen accelerated ice loss in recent decades, and scientists say the West Antarctic ice sheet – which contains enough water to raise sea levels by several meters – could be nearing a climate “tipping point.”
Using computer models, the researchers determined that faster melting of the ice shelves is inevitable in the coming decades due to warming oceans.
Even in a scenario in which greenhouse gas emissions are reduced and warming remains within the Paris Agreement’s most ambitious target – 1.5 degrees Celsius compared to the pre-industrial era – their results are essentially identical.
The study, published in the journal Nature Climate Change, examined the process of melting seawater beneath the floating ice shelves of the Amundsen Sea.
Even in the best-case scenario, ocean warming could occur three times faster in the 21st century than in the 20th century.
“alarm signal”
Kaitlin Naughten, lead author of the study, said researchers had “every reason to believe” that melting ice would contribute to sea level rise – already expected to reach a meter by the end of the century – although they did not specifically study this .
“The melting of the West Antarctic ice shelf is one of the impacts of climate change that we will likely have to adapt to,” she believes.
Millions of people around the world currently live in low-lying coastal areas and some “coastal communities will either have to be built around them or will be abandoned,” she adds.
According to Alberto Naveira Garabato, professor of physical oceanography at the University of Southampton, this study is “sobering.”
“This highlights that our decisions to date have likely led to significant melting of the West Antarctic ice sheet and subsequent sea level rise, to which we as a society will inevitably have to adapt in the coming decades and centuries,” he told Science Media Center.
But he stresses that this is also a “wake-up call” to reduce greenhouse gas emissions to avoid other serious climate impacts, including the melting of the East Antarctic ice sheet, which is currently considered more stable.
The study’s authors point out that while a significant reduction in emissions wouldn’t make a big difference to the loss of the West Antarctic ice sheet this century, it could have a significant impact in the longer term, since the ice sheet will likely take centuries, if not millennia, to recover. to fully respond to climate change.
Jonathan Bamber, a professor at the University of Bristol’s Department of Geosciences, points out that the study is somewhat limited because the researchers only used an ocean model and did not explicitly examine the effects of warming water on sea levels.
“This part of West Antarctica contains enough ice to raise sea levels by more than a meter. “That’s why it’s important to understand how it will evolve in the future,” Bamber, who was not involved in the research, told the Science Media Centre.