Eurek Alert July 19, 2018

The collapse of the two ice shelves would add 26 mm to sea levels.

An international team of scientists has shown how much sea level would rise if Larsen C and George VI, two Antarctic ice shelves at risk of collapse, were to break up. While Larsen C has received much attention due to the break-away of a trillion-tonne iceberg from it last summer, its collapse would contribute only a few millimetres to sea-level rise. The break-up of the smaller George VI Ice Shelf would have a much larger impact. The research is published today in the European Geosciences Union journal The Cryosphere.

Recent, rapid warming in the Antarctic Peninsula is a threat to ice shelves in the region, with Larsen C and George VI considered to have the highest risk of collapse. Because these large ice platforms hold back inland glaciers, the ice carried by these glaciers can flow faster into the sea when the ice shelves collapse, which contributes to sea-level rise. The new study shows that a collapse of Larsen C would result in inland ice discharging about 4 mm to sea level, while the response of glaciers to George VI collapse could contribute over five times more to global sea levels, around 22 mm.