The Thwaites Glacierknown as “glacier of the Apocalypse”, in West Antarcticait’s becoming increasingly unstable. Its ice shelf floating on the ocean is fracturing and its anchor point to land is weakening. If the glacier were to disintegrate and melt completely, the sea level could rise by more than 1 metre. The mechanism by which Thwaites is losing ice could also be common to other Antarctic platforms, with even more serious consequences. Thwaites’ alarming changes have been documented in a new study, published in the journal Journal of Geophysical Researchby an international team led by the Center for Earth Observation Science at the University of Manitoba in Canada.
The study of the fractures of the Thwaites glacier, the largest on Earth
The Thwaites glacier owes its nickname “glacier of the Apocalypse” precisely to the danger posed by its instability, since it is the widest glacier on Earth (about 120 km), up to 1200 m deep and with aextension of approximately 192,000 km², almost as much as Great Britain (209,000 km2). The glacier was examined by researchers through twenty years of satellite observationsice flow velocity measurements, and GPS data.
Thanks to this information, researchers were able to document the presence and evolution over time of multiple fractures in the ice. Fractures particularly affect the Eastern Thwaites Ice Shelf. First long fractures were generated parallel to the direction of the ice flow and then shorter transverse fractures. The study shows that their gradual development has weakened the anchoring point of the platform with the land. This way it is support also decreased that the shelf represents compared to the ice found upstream on the mainland. The inland ice thus began to slide faster towards the seafurther reducing the stability of the platform. These vicious circles are called “feedback mechanisms” and in the case of the Thwaites Glacier they amplified the collapse of the shelf.
The role of warm waters beneath the Thwaites shelf
Recent studies have highlighted their role in the destruction of Antarctic ice shelves such as Thwaites I warm, deep water flows of the circumpolar current. These waters reach the base of the shelf and erode it, weakening it and favoring the sliding of continental ice into the sea. This supply of fresh water in turn changes the vertical layering of the ocean favoring the circulation of warm, deep water. The phenomenon could also affect other Antarctic platforms, making the situation even more serious: with their merger, the global sea level is destined to increase considerably and ocean circulation to undergo significant alterations.
