Antarctic Ice Shelf Decay Threatens Catastrophic Sea Level Rise

Scientists have observed the escalating decay of Antarctic ice shelves due to rising air temperatures, causing meltwater to pool on the surface and strain the structure, potentially leading to catastrophic fractures and sea level rise. The study, led by glaciologist Alison Banwell, monitored the George VI Ice Shelf and found that repetitive flexing of the ice caused by meltwater pooling can lead to widening depressions and increased risk of collapse, with significant implications for global coastal communities and ecosystems. This description focuses on the primary topic of Antarctic ice shelf decay, the main entity of the George VI Ice Shelf, and the context of rising air temperatures and climate change. It also highlights the significant actions and consequences of the study, including the potential for catastrophic fractures and sea level rise. The description provides objective and relevant details that will help an AI generate an accurate visual representation of the article's content, such as the formation of meltwater pools, the buckling of ice, and the widening of depressions.

Bijay Laxmi

15 May 2024 00:10 EST

New Update

Antarctic Ice Shelf Decay Threatens Catastrophic Sea Level Rise

Scientists have observed the escalating decay of Antarctic ice shelves, which could lead to unprecedented fractures due to rising air temperatures. The increased global temperatures, caused by human-induced carbon emissions, are causing ice to thaw, resulting in water pooling on the ice surface. This, in turn, strains the structure below, causing it to buckle and potentially split apart.

Why this matters: The potential collapse of Antarctic ice shelves poses a significant threat to global coastal communities and ecosystems, with far-reaching consequences for human settlements, agriculture, and biodiversity. As the planet continues to warm, understanding the mechanisms behind ice shelf decay is crucial for predicting and mitigating the impacts of sea level rise.

In 2019, a team of UK and US researchers, led by glaciologist Alison Banwell, travelled to the George VI Ice Shelf to study the effect of meltwater on ice shelves. They set up time-lapse cameras, water pressure, and GPS sensors to monitor changes in a depression along the ice surface. During a record season for Antarctic ice melt and sea ice decline, they observed the formation of a meltwater pool, which caused the ice beneath the centre of the pool to buckle around 30cm. The repetitive flexing of the ice caused the depression to widen by about 30cm.

Fractured ice shelves pose a critical threat to rising sea levels. If all of Earth's ice sheets and glaciers were to melt, sea levels would rise by at least 60m . The study's findings could help explain ice shelf collapses, such as the sudden split of the Larsen B Ice Shelf in 2002.

Alison Banwell, the lead researcher, emphasized the significance of their observations: "Scientists have predicted and modelled that surface meltwater loading could cause ice shelves to fracture, but no one had observed the process in the field, until now." She added, "We believe these types of circular fractures were key in the chain reaction style lake drainage process that helped to break up the Larsen B Ice Shelf."

The George VI Ice Shelf, one of the largest ice streams of the late Pleistocene Laurentide Ice Sheet, has a long record of glacigenic debris flows and mass transport events. These have been documented through sediment cores, high-resolution seismic profiles, and multibeam swath bathymetry. The study links the records of the Hatton Slope and Fan to the changing glaciological history in Hudson Strait.

The study found that the ice shelf was grounded in Hatton Basin and on the upper slope to 700 m water depth during the last glacial cycle. The central slope sector shows the greatest shelf break progradation by till deposition, with kilometre-spaced gullies heading at 700-730 mbsl from the last major grounding of the ice stream during Heinrich event 3 (H3). The gullies pass downslope into 5 km wide valleys, which have been sites of sediment bypass since widespread meltwater flow in MIS 6.

Banwell stressed the importance of these observations, stating, "These observations are important because they can be used to improve models to better predict which Antarctic ice shelves are more vulnerable and most susceptible to collapse in the future." The study, published in the Journal of Glaciology, sheds light on the precarious state of Antarctic ice shelves in the face of climate change. As air temperatures continue to rise, the risk of catastrophic ice shelf collapse and the resulting sea level rise becomes increasingly pressing. The potential 60-meter sea level rise that could result from the complete melting of Earth's ice sheets and glaciers underscores the urgency of addressing climate change and its far-reaching consequences.

Key Takeaways

Rising air temperatures cause Antarctic ice shelves to decay, leading to potential fractures.
Meltwater pooling on ice surfaces strains the structure, causing it to buckle and potentially split.
Ice shelf collapse poses a significant threat to global coastal communities and ecosystems.
Complete melting of Earth's ice sheets and glaciers could raise sea levels by at least 60m.
Understanding ice shelf decay is crucial for predicting and mitigating sea level rise impacts.