‘Doomsday Glacier' bigger than Florida could break off in the next few years, warn scientists

The Thwaites Glacier is holding onto the ice sheet of Antarctica by its fingernails, and the world could see big changes over the next year or two, scientists have warned in a newly published study, CNN reported.

As the planet warms, giant sheets of ice near the poles have been melting off. Earlier this year, we reported how the Conger Ice Shelf in East Antarctica collapsed in a matter of days. What made the collapse even more alarming was the fact that it was located in East Antarctica, which was earlier assumed to be a solid, immovable block of ice by researchers.

In the short term, climate scientists are keen to learn which other ice shelves and glaciers are at risk of melting, and the Thwaites Glacier is one of the top concerns.

The Doomsday Glacier

The Thwaites Glacier is located in West Antarctica and is one of the widest glaciers on the planet. According to NASA, the entire West Antarctic ice sheet holds enough water to raise sea levels by 16 feet.

By the mid-1980s, researchers had determined that the glacier was at a high risk of collapse since it was grounded on the seabed rather than dry land. As a result, warm ocean currents could melt the glacier from below and destabilize it, even though evidence for the same was found only in 2020, CNN said in its report.

A study in 2021 showed that the Thwaites Ice Shelf that holds the glacier from flowing off into the ocean was also at risk of shattering in just five years. The Thwaites Glacier has an area of 74,131 sq. miles (192000 sq km), a little more than the state of Florida, and can single-handedly raise sea levels by several feet. This is why it is also called the 'doomsday glacier.'

What did the researchers find?

During an intense 20-hour mission that mapped the underwater area of the Thwaites Glacier, researchers found that the glacier was capable of receding at a much faster pace than previously thought.

The mapping also allowed the researchers to peer into the glacier's recent history in a bid to understand what it might do next. The researchers found that on two separate occasions in the past two centuries, the glacier has dislodged from the seabed and retreated at the rate of 1.3 miles (2.1 km) per year. This is twice the rate researchers have observed in the past decade.

The researchers are of the opinion that the glacier is holding onto the giant sheet of Antarctic ice by "its fingernails," and it could recede rapidly once it is past the seabed ridge that is keeping it in its place. They further warned that these changes could occur very soon and that we need to prepare for big changes in a period of time that is as short as a year or two.

The researchers will attempt to retrieve samples from the sea bed to determine when the previous retreats occurred. The research findings were published in the journal Nature Geoscience.

Abstract

Understanding the recent history of Thwaites Glacier, and the processes controlling its ongoing retreat, is key to projecting Antarctic contributions to future sea-level rise. Of particular concern is how the glacier grounding zone might evolve over coming decades where it is stabilized by sea-floor bathymetric highs. Here we use geophysical data from an autonomous underwater vehicle deployed at the Thwaites Glacier ice front, to document the ocean-floor imprint of past retreat from a sea-bed promontory. We show patterns of back-stepping sedimentary ridges formed daily by a mechanism of tidal lifting and settling at the grounding line at a time when Thwaites Glacier was more advanced than it is today. Over a duration of 5.5 months, Thwaites grounding zone retreated at a rate of >2.1 km per year—twice the rate observed by satellite at the fastest retreating part of the grounding zone between 2011 and 2019. Our results suggest that sustained pulses of rapid retreat have occurred at Thwaites Glacier in the past two centuries. Similar rapid retreat pulses are likely to occur in the near future when the grounding zone migrates back off stabilizing high points on the sea floor.