The “Doomsday Glacier” the Size of Florida Could Destroy Coastal Cities

Deep in West Antarctica sits a massive glacier roughly the size of Florida, and scientists are increasingly concerned about its stability. Known as the "Doomsday Glacier," it has become a focal point in discussions about rising sea levels and global climate risk.

Recent research shows that parts of the glacier are melting faster than expected, raising the possibility of significant changes to coastlines around the world. If large sections were to collapse, the impact could be felt far beyond Antarctica. Here's what scientists know so far and why this glacier matters.

The Thwaites Glacier is held to the greater continent of Antarctica by an ice shelf on its ocean-facing border. This massive, frozen shelf prevents the Thwaites Glacier from breaking off the mainland. Recent scientific studies have all reached the same conclusion. Although the ice at the bottom of this shelf is melting more slowly than they had predicted, the Thwaites Glacier is melting much faster at crucial cracks, fissures and formations known as staircases.

Because climate change is accelerating, the Doomsday Glacier releases more of its ice into the ocean annually. Already today, it sheds billions of tons of ice per year. That makes up as much as 4% of the rise in sea levels every year. Since the turn of the millennium, the glacier has retreated from the seafloor on which it rests by almost nine miles. With every incursion, warmer sea water has greater access to the main body of the glacier.

Should the Thwaites Glacier collapse, sea levels will rise more than two feet in a single event. People living on the coasts of every continent would feel this impact. These communities would essentially be wiped out, and new coastlines drawn further inland. Until, of course, the next catastrophic event raised the sea level even further, as climate change snowballs onward.

In fact, the Doomsday Glacier's collapse would indeed likely cause a domino effect. Other glaciers bounded by Thwaites would collapse, releasing just about all of the ice in West Antarctica. The destruction of Thwaites itself could raise sea levels two feet. But its knock-on effects could ultimately cause them to rise more than ten feet.

Imagine trying to defuse a time bomb, but you don't even know how long the countdown is. This is the conundrum faced by climate scientists examining Thwaites Glacier. Possibly, the ice shelf could hang on, even while eroding, for hundreds of years longer. Or it could happen tomorrow. Once the "glacier bomb" goes off, the effects will be both difficult to predict and impossible to reverse.

These are the difficulties faced by the scientists attempting to learn all they can about the Thwaites Glacier. They seek this knowledge in part to try to predict, or even prevent, the day of Thwaites' doom.

In 2019, the Thwaites Glacier Collaboration was created, sending British and American scientists to study the Doomsday Glacier. Trying to learn more about the effects of global warming on the ice shelf, they took an ice sample from 2,000 feet inside the glacier. They sent a number of gauges and instruments deep within the hole they had bored. They were also able to deploy Icefin, a remotely controlled drone that could travel to waters human life couldn't possibly tolerate. This torpedo-shaped robot took photos, video and gauged the traits of the environment such as salinity, temperature and current strength. Icefin was able to collect this abundance of data over a vast area, from the sea floor to the ice.

We'll start with the only good news. Beneath the receding glacier, the rate of melt is lower than earlier models showed. The recession is still meaningful, however, at 2 to 5.4 meters annually. The Thwaites Glacier Collaboration were able to learn the reason for the slower-than-predicted melt. Beneath the shelf, there is a layer of water which is colder and more frequently refreshed by the currents. This layer lives between the bottom of the ice shelf and the Antarctic Ocean.

Now for the bad news, and there's plenty of it. First off, although the glacier is melting more slowly than expected, it is still retreating more rapidly than anticipated.

(Let's unpack that a little: Even the healthiest glaciers are in a constant state of melting. It's just that the healthiest glaciers are also constantly being replenished by the addition of new ice. You can think of it like the coldest end of the precipitation cycle covered in most Earth Science classes: evaporation, precipitation and accumulation all occur in Antarctica. It's just very, very cold when they do!)

Back to the problem with the Doomsday Glacier: even though it's melting at a slower-than-expected rate, the size of the glacier is still receding over time. Relatedly, here's a good-news/bad-news finding: with Icefin's help, the expedition discovered that the underwater landscape of this glacier was far more topographically rich than they had predicted. Where they expected a similar topography to the parts of glaciers that are above water, these scientists instead found a world of terraces they say resemble staircases. They also found crevasses — narrow canyons where the ice shelf has cracked, going as deep as the shelf itself.

The Thwaites Collaboration also found that the Doomsday Glacier was melting most rapidly in these crevasses. These huge cracks were natural funnels for warmer and saltier water to find its way deep into the core of the glacier. Here, it can accelerate the melt rate even further, burrowing a deeper furrow at Thwaites' most vulnerable potential breaking points. The scientists studying Thwaites have stated that this process is the most likely trigger for the total collapse of the ice shelf protecting the glacier.

We have to take a moment to point up that these discoveries were groundbreaking. The Thwaites Collaboration provided more knowledge than we have ever had before about exactly which parts of the Doomsday Glacier are melting, at what rate, and what form the glacier's destruction will ultimately take. This is, in a sense, grim work — but we are better off for having this data.

Alarmingly, this is only the latest study of the Thwaites Glacier evidencing its swift decline. A 2021 study's findings matched the Thwaites Collaboration's, predicting Thwaites' ice shelf would shatter within the next five years — and that was two years ago.

The only bright side is that the future remains unwritten, and that with more knowledge of the dire impacts the death of the Doomsday Glacier will have, the greater the chance that the general public will demand that their leaders take global boiling seriously, and fight it with the urgency required. And though there may be no saving the Thwaites Glacier, a blueprint for responding to its collapse will ultimately save lives and property in coastal communities throughout the world.

A big ice cube as far as from civilization as possible breaks apart, and the whole world suffers. We guess it goes to show we really are interconnected.

The image featured at the top of this post is ©NNER / Shutterstock.com.