Glaciers in Antarctica steal ice from each other at a surprising rate

Scientists from the University of Leeds (United Kingdom) have documented an unusual phenomenon among glaciers in Antarctica. Using high-resolution satellite data, they observed that one glacier can capture ice from its neighbor – a phenomenon described by researchers as ice piracy. Although the migration of ice masses between neighboring streams is not new, this process has been recorded for the first time on such a short timescale – under two decades.

Dynamic glaciers in Antarctica

Previously, it was believed that such interactions required hundreds or even thousands of years. However, research showed that one of the glaciers in West Antarctica moved in a way that suggested continuous pilfering of ice from its slower neighbor. According to the research team’s estimates, the annual balance of this transfer could exceed 700 meters, which is equivalent to the length of seven football fields.
The most significant speed changes were observed in the Kohler East and Smith West ice streams, which accelerated, while Kohler West, contrary to the regional trend, slowed down by about 10%. Researchers suspect that this slowdown may be a result of a change in the glacier’s surface slope, caused by uneven melting rates of neighboring ice masses.

This phenomenon is crucial for modeling ice sheet dynamics and forecasting the rate of sea-level rise. Glaciers that lose mass to their neighbors may play a lesser role in delivering ice to the ocean in the future, while their faster-moving counterparts may do the opposite. Observations by the scientists from Leeds, published in specialized glaciological journals, confirm how complex and dynamic Antarctica’s glacier system is. New satellite tools now allow researchers to capture phenomena that were previously considered impossible to observe within a single generation

Scientists express surprise

According to the research team from the University of Leeds, identifying such rapid ice flow between neighboring glaciers is a significant step toward better understanding the dynamics of the Antarctic ice sheet and its potential impact on global sea-level rise. The study’s lead author, Dr. Heather Selley, who conducted these analyses during her doctoral studies at the School of Earth and Environment, did not hide her surprise.

We didn’t know that ice streams could intercept masses from each other in such a short time. It’s a truly fascinating discovery, she admitted. She added that until now, such processes were considered to span hundreds or thousands of years. Here, we observe real changes in less than 18 years, recorded thanks to precise satellite data. It’s an unprecedented situation, the study’s author emphasized.

Causes of glacier movement speed

The team of scientists used a method of tracking ice surface movement, analyzing changes in the position of characteristic structures such as crevasses, fractures, or other permanent elements visible in satellite images. Data from the CryoSat mission, conducted by the European Space Agency (ESA), was also used to assess the rate of ice mass loss, enabling precise measurements of ice sheet thinning. As Pierre Dutrieux, co-author of the study and a specialist in polar oceanography, explained, it was this data that allowed researchers to capture the phenomenon described as ice piracy.

The ice flow that previously fed one glacier gradually starts moving towards its neighbor because the warming ocean melts the grounding zone and changes the configuration of the entire flow system,” he explained.

The study aimed to identify the mechanisms influencing glacier dynamics variability. Scientists took into account factors such as rising ocean and air temperatures, changes in water circulation, and snowfall variability. Ultimately, it was shown that the observed redirection of ice mass flow significantly affects the amount of ice delivered to ice shelves – vast, floating structures that play an important role in stabilizing the Antarctic ice sheet.

Understanding these processes is crucial for sea-level rise predictions. It is currently estimated that by the end of the 21st century, over 410 million people worldwide could be in zones at risk of flooding due to continued glacier melting and rising sea levels. In just the last decade, the global sea level has risen by more than 10 cm, and data from polar regions indicate that this trend may accelerate.