Towering ice falls from Argentina’s Perito Moreno glacier

A dramatic spectacle unfolded at the Perito Moreno glacier in Argentina as it released a towering block of ice, measuring 70 metres tall, into the vibrant aquamarine waters below. 

Visitors flocked to the site, eagerly waiting on viewing platforms for the next heart-stopping moment of calving, a process where massive ice chunks break off the glacier. 

However, local guides and glaciologists are growing increasingly concerned about the size of these ice collapses. 

Once a resilient giant, Perito Moreno has started showing signs of retreat, raising alarms amid a backdrop of global glacial melting driven by climate change. 

This shift marks a significant change for a glacier that had defied typical trends, leaving experts and onlookers worried about its future in an era of warming temperatures.

“Ice-calving events of this size haven’t been very common at the Perito Moreno glacier over the past 20 years,” said Pablo Quinteros, an official tourist guide at Los Glaciares National Park in the southern province of Santa Cruz.

“It’s only in the last four to six years that we’ve started to see icebergs this big,” he told Reuters during a visit in April.

The glacier’s face, which flows down from Andean peaks to end in the waters of Lake Argentina, had for decades held more or less steady, some years advancing and others retreating. But in the last five years, there’s been a firmer retreat.

“It had been in more or less the same position for the past 80 years. And that’s unusual,” said Argentine glaciologist Lucas Ruiz with state science body CONICET, whose research focus is the future of Patagonian glaciers in the face of climate change.

“However, since 2020, signs of retreat have begun to be seen in some parts of the Perito Moreno glacier’s face.”

He said that the glacier could rebound as it has done before, but that for the moment it was losing between one and two meters of water equivalent per year, which, if not reversed, could lead to a situation where the loss accelerates.

A 2024 report, co-authored by Ruiz and presented to Argentina’s Congress, showed that while Perito Moreno’s mass has been overall stable for half a century, the period since 2015 has seen the fastest and most prolonged loss of mass in 47 years, on average losing 0.85 meters per year.

Glaciers worldwide are disappearing faster than ever, with the last three years seeing the largest glacial mass loss on record, according to a March UNESCO report.

‘You can’t grasp at the immensity of it’

Ruiz said the instruments his research team used to monitor the glacier had shown an increase in air temperature in the area of around 0.06 degrees Celsius per decade and precipitation decreasing, meaning less accumulation of snow and ice.

“The thing with Perito Moreno is that it took a while, so to speak, to feel the effects of climate change,” Ruiz said. Now, however, the accumulation of ice at the top of the glacier was being outpaced by melting and calving at the bottom.

“The changes we are seeing today clearly show that this balance of forces… has been disrupted, and today the glacier is losing both in thickness and area.”

For now, the glacier remains an awe-inspiring attraction for travellers, who board boats to see the calving and the huge icebergs floating around the lake up close.

“It’s insane. The most incredible thing I’ve ever seen,” said Brazilian tourist Giovanna Machado on the deck of one of the boats, which have to be careful of sudden ice falls.

“Even in photos, you just can’t grasp the immensity of it, and it’s perfect. It’s amazing. I think everyone should come here at least once in their lifetime.”