Antarctica's Thwaites Glacier (Credit: Jim Yunge/ NASA/ Public Domain)

The Thwaites Glacier in West Antarctica is the world's largest and widest glacier. The massive ice sheet stretches 80 miles (129 km) across, roughly the size of Florida. The glacier loses about 50 billion tons of ice annually and already accounts for about 4 percent of the planet's current sea level rise. If it were to melt completely, it could raise global sea levels by about two feet (61 cm). This would displace millions of people in coastal communities worldwide. It is no wonder the ice mass has been nicknamed "Doomsday Glacier."

The glacier's erosion is largely attributed to the downward-sloping land on which it sits. This allows warm seawater to seep underneath and melt it from below. Researchers have known about this phenomenon for decades. However, a new study indicates that the Thwaites Glacier is being exposed to more warm ocean water than previously thought. This could cause it to melt at a much faster rate than scientists had initially estimated.

The Thwaites Glacier may be melting faster than believed (Credit: Tom Slate/ CPOM/ BBC)

The research team was led by Professor Eric Rignot at the University of California, Irvine (UC Irvine). They reached this conclusion after analyzing satellite data collected from March to June 2023. The scientists found that during each 12-hour tidal cycle, warm seawater moves underneath the glacier for about four miles (6.4 km). This is a much longer distance than previously thought. As the tide retreats, it leaves the warm seawater behind and carries the freshwater from the melting glacier into the ocean. This constant inflow of freshwater adds to sea level rise over time.

"There are places where the water is almost at the pressure of the overlying ice, so just a little more pressure is needed to push up the ice," says Rignot. "The water is then squeezed enough to jack up a column of more than half a mile of ice."

An aerial image of the Thwaites Glacier (Credit: NASA/ Public Domain)

The scientists revealed their findings in the journal Proceedings of the National Academy of Sciences on May 20, 2024. They believe the new evidence suggests sea levels could rise to a dangerous degree faster than current estimates.

"We really, really need to understand how fast the ice is changing, how fast it is going to change over the next 20 to 50 years,” said Christine Dow, an associate professor at the University of Waterloo and one of the study’s authors. “We were hoping it would take a hundred, 500 years to lose that ice. A big concern right now is if it happens much faster than that.