Antarctica's Thwaites Glacier set to retreat 'further and faster'

A significant section of the Antarctic Ice Sheet continues to show signs of retreat, as a collaborative effort between UK and U.S. scientists unveils new findings about the mechanisms and timing that could trigger a sudden collapse. 

Since 2018, researchers have been exploring the rapidly evolving environment at the remote Thwaites Glacier in West Antarctica. Last week, scientists convened at the British Antarctic Survey (BAS) in Cambridge, to discuss their observations and recent study results.

Before the launch of the International Thwaites Glacier Collaboration (ITGC), little was understood about the factors driving the retreat of this massive glacier, one of the largest and most rapidly changing glaciers in the world. 

"If it collapsed entirely, sea levels would rise by 65 cm," warned Rob Larter, a marine geophysicist at BAS and member of the ITGC.

Thwaites Glacier, roughly equivalent in size to Great Britain or the U.S. state of Florida and over 2,000 meters thick in certain areas, has seen a dramatic increase in the ice volume flowing into the sea - from less than 1,000 gigatons per year in the 1990s to over 2,000 gigatons annually in the 2010s. 

The Amundsen Sea Embayment, which encompasses Thwaites and adjacent glaciers, is responsible for eight percent of the current rate of global sea level rise, estimated at 4.6 millimeters each year.

The mission of the ITGC is to deepen the understanding of critical physical processes influencing Thwaites Glacier in both the current climate and ancient contexts. 

"Thwaites has been retreating for more than 80 years, accelerating considerably over the past 30 years, and our findings indicate it is set to retreat further and faster," stated Larter.

Significant loss by 23rd century

This research aims to predict the ongoing rate and magnitude of sea level rise, which could significantly affect millions of people living in coastal regions, from Bangladesh to low-lying Pacific islands, as well as major cities like New York and London. 

Underlining the urgency, Larter added, "There is a consensus that Thwaites Glacier retreat will accelerate sometime within the next century. However, there is also concern that additional processes revealed by recent studies, which are not yet well enough studied to be incorporated into large-scale models, could cause retreat to accelerate sooner."

The implications of these findings are profound, suggesting that Thwaites Glacier and much of the West Antarctic Ice Sheet could be significantly diminished by the 23rd century. Thwaites is particularly vulnerable; its ice rests on a bed that lies far below sea level, sloping downwards toward the center of West Antarctica.

Scientists have been employing advanced technologies such as underwater robots and innovative survey techniques, alongside new methods for modeling ice flow and fracture. These approaches have yielded insights that enhance the accuracy of predictive computer models, although a comprehensive understanding of the glacier's future remains elusive.

Ted Scambos, the U.S. science coordinator of the ITGC and a glaciologist at the University of Colorado, expressed concern over the latest predictions.

"It's concerning that the latest computer models predict continuing ice loss that will accelerate through the 22nd century and could lead to a widespread collapse of the West Antarctic Ice Sheet in the 23rd," he said.

"Immediate and sustained climate intervention will have a positive effect, but a delayed one, particularly in moderating the delivery of warm deep ocean water that is the main driver of retreat," he noted, emphasizing the importance of action.

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