How Argentina’s most famous glacier, once unusually stable, is now crumbling

However, in recent years, the size of the ice chunks breaking off has raised concern among scientists and experts. The latest ice calving event has further heightened this concern. Note that for several decades the Perito Moreno glacier was unusually stable, unlike other glaciers across the world, amid soaring global temperatures. But this changed around 2020.

Here is a look at the situation.

An iconic site

The Perito Moreno glacier, also called the ‘White Giant’, is located near the city of El Calafate in the Argentine province of Santa Cruz, and comes under the Los Glaciares National Park — a UNESCO World Heritage Site.

It was formed during the last Ice Age, which occurred approximately 18,000 years ago. Estimates suggest that the glacier is 30 km long, and has a towering height of 60 m above the water level. Due to its enormous size, it is a major source of freshwater for Argentina.

Since at least 1917, the glacier has witnessed numerous large-scale ice calving events due to its forward movement. The event creates a thunderous sound as colossal blocks of ice break from the glacier and submerge into the water. The stunning visuals of calving have, over the years, attracted tourists from around the world.

The retreat

Although the calving events at the Perito Moreno glacier are a natural phenomenon, they have been growing in size in recent years.

Speaking about the latest event, which took place on April 21, Pablo Quinteros, an official tourist guide at Los Glaciares National Park, told Reuters, “Ice calving events of this size haven’t been very common at the Perito Moreno glacier over the past 20 years… It’s only in the last four to six years that we’ve started to see icebergs this big.”

The glacier was mostly stable for decades, as in some years it advanced and others retreated. However, in the last five years, the glacier has retreated quite firmly. A 2024 report, backed by the Argentine government, found 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 metres per year, according to a report by Reuters.

In 2023, scientists at the Argentine Institute of Glaciology and Environmental Sciences (IANIGLA) told the media that since 2020, the Perito Moreno glacier had seen a loss of mass consisting of more than 700 m, approximately seven blocks.

The retreat has been triggered by an obvious culprit: global warming. Argentine glaciologist Lucas Ruiz with state science body CONICET told Reuters, “The thing with Perito Moreno is that it took a while, so to speak, to feel the effects of climate change.”

He said that the area around the glacier witnessed an increase in air temperature of around 0.06 degrees Celsius per decade and precipitation, meaning less accumulation of snow and ice.

A global phenomenon

The Perito Moreno glacier is now part of the long list of glaciers around the globe which are disappearing faster than ever due to rising temperatures. Glaciers have been losing 273 billion tonnes of ice each year — equivalent to how much water Earth’s entire population would consume over a period of 30 years — for the last 25 years, according to a research paper published in the journal Nature in February this year.

The paper, ‘Community estimate of global glacier mass changes from 2000 to 2023’, also said that the ice loss had led to the sea level rising by almost 2 cm this century alone. While the 2 cm sea level rise may seem insignificant, it can have disastrous consequences for the world.

In March, a UNESCO report said that since 1975, glaciers, which do not include the Greenland and Antarctica ice sheets, had lost more than 9,000 billion tonnes of mass. “This is equivalent to a huge ice block of the size of Germany with a thickness of 25 metres,” Michael Zemp, director of the Switzerland-based World Glacier Monitoring Service, had said during the release of the report.