A glacier the size of Philadelphia just did something scientists have never seen. They're alarmed.

Evan Porter
Tue, 11 Nov 2025 17:53:42 +0000
Global warming, Glaciers, Glacier, Antarctica, Arctic, Arctic ice, Environment, Conservation, Earth, Nature, Science, Climate change

Signs of climate change are all around us, from rising sea levels, to more frequent wildfires, to something as subtle as the warm breeze that seems to last longer and longer into winter every year.

But scientists have been keeping an especially close eye on Earth's glaciers, giant mountains of ice that have been observed steadily melting since the 1970s. Tracking the size and movement of glaciers gives us a good idea as to how rising temperatures may be affecting the global habitat, and of course, the more they melt, the more sea levels rise all over the world.

Recently, though, researchers have become alarmed that a slow, steady melt may be the least of our problems.

A glacier the size of Philadelphia recently "retreated"—or shrank—by about half its size in just two months. That's the fastest pace on record.

Hektoria is a fascinating case study in climate change. Photo by Torsten Dederichs on Unsplash

Hektoria is a glacier in Antarctica that was, not too long ago, about 115 square miles in size. That makes it about the size of a city like Philadelphia or Baltimore. That is, until 2022, when the front face of the glacier retreated about five miles in just two months. By March of 2023, the glacier had retreated a total of 16 miles.

Not only was this the fastest glacier collapse scientists have ever seen, but it wasn't even a close competition. What happened to Hektoria is estimated to be about 10 times faster than any other glacier retreat we've witnessed.

A new study claims to have figured out why Hektoria retreated so fast. Essentially, upward forces from ocean water caused huge chunks of ice to break off and float away after the glacier lost its grip on the bedrock below. This sounds like something that would happen all the time, but it's never been recorded at this scale before.

And it definitely has scientists more than a little alarmed.

"What we see at Hektoria is a small glacier, but if something like that were to happen in other areas of Antarctica, it could play a much larger role in the rate of sea-level rise," said Dr. Naomi Ochwat, research affiliate at the University of Colorado Boulder and post-doctoral researcher at the University of Innsbruck—and also one of the lead authors of the study.

"Hektoria’s retreat was heavily influenced by climate change," according to CNN. "The loss of sea ice in the ocean next to Hektoria, believed to have been driven by ocean warmth, allowed wave swells to reach the fast ice and break it up, leaving the glacier exposed to ocean forces."

The animation below explains what happened to Hektoria:

- YouTube www.youtube.com

Though Hektoria was a unique and record-setting event, it's not the first instance we've seen of massive ice loss.

Over a decade ago, filmmakers captured the largest glacier calving ever recorded when the Ilulissat Glacier broke apart. A three-mile by one-mile chunk broke off right in front of their eyes.

That's a segment the size of Lower Manhattan. But the walls of ice were up to three times as tall as New York's tallest skyscraper.

It was truly a monumental and frightening sight to behold.

- YouTube www.youtube.com

As harrowing as it all seems, scientists and engineers are cooking up some pretty bold ideas to save the glaciers.

For decades, some of the world's brightest minds have been brainstorming ways to slow down glacial melt and calving. One wild idea involves building a barrier across the Bering Strait that would reduce powerful ocean currents that might break apart glaciers.

Another idea proposed in the 1980s suggests pumping seawater onto the floating front ends of glaciers, where it would freeze and thicken the glacier's protective outer shelf.

A more recent concept would drill holes in glaciers so that engineers could pump out the layer of water that rests beneath them, creating room for the ice to freeze and settle directly on the bedrock, anchoring the glaciers in place.

These ideas, for the most part, are ambitious, complex, and a bit of a Hail Mary. They also don't solve the root causes of climate change or address any symptoms other than rising sea levels.

But there's good news on that front, too. In recent years, through an unprecedented campaign of international cooperation, we've all but healed the ozone layer. Clean, renewable energy sources like wind and solar are rapidly overtaking fossil fuels, and the Paris Agreement and Green Deal have made incredible strides in reducing greenhouse gas emissions in Europe.

There is plenty of good news to be found, but maintaining a sense of urgency is key, and our efforts need to speed up, ASAP. Hektoria was a fascinating warning sign of what might happen to much larger glaciers if we can't get rising ocean temperatures under control, and fast.