🌡️ Antarctica has lost 5,000 mi² of anchored ice (13,000 km²)

A vast study spanning thirty years shows that the majority of Antarctica's coastline is not moving, while some areas are undergoing dramatic retreat. How does this general stability coexist with massive ice loss?

To clarify this question, glaciologists have analyzed three decades of satellite observations. They combined data from many space missions, including those from the European Space Agency and commercial satellites. This approach made it possible to create the first continent-wide map of grounding line movement, where the continental ice meets the ocean.


The results, published in Proceedings of the National Academy of Sciences, indicate that 77% of the Antarctic coast has remained stable since 1996. Yet, in the west of the continent, the Antarctic Peninsula, and parts of the east, the ice has retreated significantly. In total, nearly 5,000 square miles (13,000 square kilometers) of anchored ice have disappeared.

The most marked retreat concerns the glaciers of the Amundsen Sea and the Getz region. For example, Pine Island Glacier has retreated by 20 miles (33 kilometers), and Thwaites Glacier by 16 miles (26 kilometers). Scientists generally attribute these changes to warm ocean water infiltrating beneath the ice shelves, thinning them from below.

However, a mystery remains in the northeast of the Antarctic Peninsula. There, glaciers like Edgeworth or Hektoria have retreated several kilometers, without the presence of warm water being confirmed. Researchers admit that another factor is at play, but they have not yet identified it.

This detailed map of grounding line movements now serves as a reference for sea level rise prediction models. Modeling teams must be able to reproduce these thirty years of observations to validate their projections. Otherwise, they will have to revisit their assumptions.

What is the grounding line?

The grounding line is the boundary where Antarctica's continental ice begins to float on the ocean. It marks the transition between ice anchored to the ground and the floating ice shelves. Its position is a key indicator of glacier stability.

When the grounding line retreats, it means the ice is losing its anchor and the glacier becomes more vulnerable. This retreat can lead to an acceleration of ice flow into the ocean, thus contributing to sea level rise.

Scientists measure this line using satellite radars, which penetrate clouds and polar darkness. These instruments detect the subtle movements of the ice over long periods, allowing for precise mapping of changes.