Humans have accelerated the melting of one of Antarctica’s most important glaciers

The Pine Island Glacier is situated in West Antarctica and flows into the Amundsen Sea. It is considered one of the major sources of ice loss in the region and an important factor in future sea-level rise.

The study has been published in the journal *The Cryosphere*.

Details

The research was carried out by scientists from King’s College London, the British Antarctic Survey and other scientific organisations. They compared two scenarios: how the glacier would evolve given anthropogenic warming, and how it might retreat in the absence of human influence on the climate.

According to the calculations, by 2015, in the scenario without human influence, the glacier’s grounding line would have retreated by approximately 4 km less. This is the point where the glacier ceases to rest on a rocky bed and begins to float as ice shelf. It is the movement of this line that indicates how far the glacier is ‘retreating’ inland.

The authors believe that greenhouse gas emissions have accelerated the retreat of Pine Island by approximately 18–20 per cent since the 1940s. This has added several kilometres to its movement inland.

Why this glacier is so important

Pine Island is not just one of Antarctica’s many glaciers. It drains much of the West Antarctic Ice Sheet and is one of the major contributors to global sea-level rise.

The problem is that the glacier is in contact with the ocean. Warm water can seep beneath its ice shelf, erode the ice from below and accelerate its retreat. Geological data show that the glacier’s rapid retreat began as early as the 1940s, probably due to increased infiltration of warm ocean water beneath the ice shelf. Since then, anthropogenic ocean warming has intensified the process.

In other words, the glacier is losing stability not only because the air is getting warmer. The ocean is particularly important for Antarctica: it can erode the ice from below.

What exactly did the scientists do?

This study falls under the field of climate attribution. This approach is often used when scientists are trying to understand to what extent a specific event — a heatwave, a flood or a drought — has become more likely or more severe as a result of climate change.

This is more difficult to do with Antarctic glaciers. They have a long memory: their current state may be influenced not only by the climate of recent decades, but also by how the glacier changed thousands of years ago. The authors explicitly note that the glacier’s long-term history over the past 10,000 years may also be significant for its current retreat.

Nevertheless, the researchers have, for the first time, provided a quantitative assessment of the role of human activity in the case of a major Antarctic outlet glacier. According to *The Cryosphere*, the retreat observed during the industrial era would be unlikely to have occurred on such a scale without anthropogenic climate change.

In simple terms

A glacier can be thought of as a huge river of ice that flows slowly towards the ocean. Where the ice no longer rests on the seabed but begins to float, there is an important boundary — the grounding line.

As warm water erodes the ice from below, this boundary retreats further inland. The further it retreats, the more ice can begin to flow into the ocean at a faster rate.

New research suggests that, even without human-induced warming, Pine Island Glacier might still be retreating. But not by nearly as much. By 2015, human activity had contributed to the retreat of this boundary by approximately 4 km.

Why this matters beyond Antarctica

Antarctic glaciers affect sea levels worldwide. If they lose more ice, the water in the oceans rises. This is important for coastal cities, ports, islands and low-lying areas.

Pine Island is particularly important because it is connected to the West Antarctic Ice Sheet. This region has long been a cause for concern among climate scientists: part of its ice lies on a bed below sea level, making it vulnerable to warm ocean water.

This does not mean that sea levels will rise sharply tomorrow. Ice sheets react slowly. But that is precisely the problem: the consequences of the current warming could last for centuries.

What lies ahead

Models suggest that later this century, the Pine Island Glacier may temporarily stabilise if its retreat reaches an underwater ridge. Such a feature could temporarily slow the movement of the ice.

But this does not necessarily mark a reversal. If warming continues, the pause may prove to be temporary. The authors estimate that human influence could once again become the dominant factor driving retreat as early as the 22nd century.

As the study’s lead author, Alex Bradley, said, ice sheets react slowly, and the consequences of today’s emissions will continue to influence ice loss in Antarctica for centuries to come.

Background

Pine Island has long been considered one of Antarctica’s most vulnerable glaciers. It is rapidly losing ice, retreating and affecting the balance of the West Antarctic Ice Sheet.

The novelty of this work lies in the fact that the scientists did not merely describe the retreat, but attempted to quantitatively separate the contribution of human-induced climate change from other factors. *The Cryosphere* describes the article as one of the first formal assessments of the link between anthropogenic warming and the retreat of the Pine Island Glacier.

Source

Study: Alexander T. Bradley, David T. Bett, C. Rosie Williams, Robert J. Arthern, Paul R. Holland, James Byrne, Tamsin L. Edwards, Mira Adhikari — “Detection and attribution of the role of anthropogenic climate change in the industrial-era retreat of the Pine Island Glacier”, The Cryosphere, 2026.