Antarctic ice shelves break under the weight of meltwater • Earth.com

As the world witnesses the consequences of a warming climate, the Antarctic ice shelves face a precarious future. Recent research led by the Cooperative Institute for Research in Environmental Sciences (CIRES) has uncovered alarming evidence about how these ice structures not only bend under pressure, but also actively fracture.

Ice shelves under pressure

Floating ice shelves in Antarctica act as critical barriers, preventing glacial ice from entering the ocean. However, when air temperatures rise, melting glacial ice forms puddles on these shelves, making them significantly heavier.

This increased weight causes the ice to bend and, as recently observed, break dramatically. Such faults could lead to the eventual collapse of these ice shelves, further exacerbating sea level rise – a worrying prospect for the world’s coastal areas.

Alison Banwell, a CIRES scientist at the Earth Science and Observation Center and lead author of a recent study, highlighted the crucial role of ice shelves in maintaining the stability of the Antarctic ice sheet.

“Ice shelves are extremely important to the overall health of the Antarctic ice sheet because they support or hold back glacial ice on land,” Banwell explains.

This study, which marks the first field observation of its kind, confirms long-standing theoretical models that predicted the susceptibility of ice shelves to fractures due to surface meltwater.

Antarctic ice shelves break

Banwell, along with her team from the University of Cambridge, the University of Oxford and the University of Chicago, conducted field research on the George VI Ice Shelf, located on the Antarctic Peninsula.

In November 2019, the team set up camp around a known depression in the ice, a place where meltwater can accumulate. Equipped with high-precision GPS stations, water pressure sensors and a time-lapse camera system, they meticulously recorded the changes occurring on the ice surface.

Despite the disruptions caused by the COVID-19 pandemic, the team resumed their work in November 2021. They found that the remaining instruments had captured significant ice movement and the formation and drainage of a meltwater lake during the record-high melt season of 2019. 2020.

The data showed that the ice in the center of the lake bent downward about a foot due to the weight of the accumulated meltwater, while the horizontal distance between the edge of the lake and the center also increased, indicating the formation and widening of circular faults on the ice shelves. .

Ice shelves breaking and chain reaction of collapse

These observations provide crucial insights into the mechanisms of ice shelf disintegration. “This is an exciting discovery,” said Banwell. “We believe these types of circular faults were key in the chain reaction-like lake drainage process that helped break up the Larsen B ice shelf.”

Her reference to the abrupt collapse of Larsen B in 2002, which abruptly dried up thousands of meltwater lakes, underlines the potential for similar events if current trends continue.

Practical insights and global implications

The results of this study are not just academic; they have practical implications for improving models that predict the stability of Antarctic ice shelves.

By understanding the specific conditions that lead to the breakage of ice shelves, scientists can better predict which shelves are most vulnerable to collapse. This knowledge is crucial for anticipating the consequences of these collapses for global sea levels.

Furthermore, as evidence accumulates, the urgency to address the root causes of climate change becomes even clearer.

Antarctic ice shelves serve as a stark reminder of the broader environmental challenges that lie ahead, and the need for sustained scientific research and environmental management to mitigate these global threats.

Antarctic ice shelves

Antarctic ice shelves are huge floating ice platforms that form where the continent’s ice sheets meet the sea. These shelves are fed by the slow flow of glaciers and thick ice from Antarctica’s interior. They are crucial components of Earth’s climate system because they act as barriers that regulate the flow of ice into the ocean.

Stability of ice shelves

When ice shelves are stable, they slow the discharge of ice from glaciers. However, if they thin or break up, it could lead to faster ice flow into the ocean, contributing to sea level rise.

The stability of ice shelves is affected by both atmospheric and oceanic temperatures. Warmer air can melt the surface of the shelves, while warmer ocean currents can erode their undersides.

This double attack can leave them vulnerable to disintegration and disintegration. Events such as the dramatic collapse of the Larsen A and B ice shelves in 1995 and 2002, respectively, highlight the sensitivity of ice shelves to changing climate conditions.

Ecological role

Moreover, Antarctic ice shelves are also important for their ecological role. The underside of these ice platforms supports a unique ecosystem that includes algae, krill and several fish species, which in turn are crucial for larger predators such as whales and seals.

Polar research

Scientific studies of these ice shelves are critical to understanding not only the mechanisms of their change, but also the broader implications for global sea levels and climate feedback loops. As such, they are a focal point of polar research, often involving satellite monitoring, field expeditions and advanced climate models.

The research has been published in the Journal of Glaciology.

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