Antarctica’s Thwaites Glacier, capable of raising sea levels by several feet, is retreating faster than previously thought.
Two ice sheets, the East and West Antarctic Ice Sheets feed many distinct glaciers. A study finds that two major glaciers in the West Antarctic Ice Sheet (WAIS), the Thwaites and Pine Island glaciers, are losing ice at the fastest rate for at least 5,500 years.
The study published Monday in the journal Nature Geoscience, and led by researchers from the University of Maine and the British Antarctic Survey, in collaboration with Imperial College London, mapped the Thwaites glacier’s historical retreat, hoping to learn from its past what the glacier will likely do in the future.
In mapping the Thwaites Glacier, scientists found that over the past two centuries, the base of the glacier dislodged from the seabed and retreated at a rate of 1.3 miles (2.1 kilometers) per year. That’s twice the rate that scientists have observed in the past decade or so, reports CTV News.
The researchers used radiocarbon dating to examine sea shells and very old penguin bones found on the remnants of Antarctic beaches in the area to get estimates of the age of the artifacts.
This helped the scientists determine how long the shells and bones had sat above the local sea level and how old these beaches are. Understanding when these beaches first appeared allowed researchers to reconstruct the rate of local sea level rise – an indirect metric of ice loss – around this especially vulnerable glacier.
SciTechDaily explains: “By pinpointing the precise age of these beaches, they could tell when each beach appeared and therefore reconstruct changes in local, or ‘relative’, sea level over time.”
Co-author Dr. Dylan Rood of Imperial’s Department of Earth Science and Engineering, in discussing the retreat of the Thwaites and Pine Island glaciers said: “We reveal that although these vulnerable glaciers were relatively stable during the past few millennia, their current rate of retreat is accelerating and already raising global sea level.
“These currently elevated rates of ice melting may signal that those vital arteries from the heart of the West Antarctic Ice Sheet have been ruptured, leading to accelerating flow into the ocean that is potentially disastrous for future global sea level in a warming world. Is it too late to stop the bleeding?”
“You can’t take away Thwaites and leave the rest of Antarctica intact,” said Alastair Graham, a marine geologist at the University of South Florida and the co-author of the study, in a phone interview with The Washington Post.
He described the consequences of losing Thwaites as “existential.”
