New research exposes melt of West Antarctic Ice Sheet

This new insight from the University of Southampton into the dynamics of under-water ice shelves comes from a recently published study in Science Advances.

The West Antarctic Ice Sheet, which has been dropping mass over the recent decades, could potentially cause a five-metre rise in global sea levels if entirely melted. The melting primarily occurs beneath the floating ice sheet due to the intrusion of the warm Circumpolar Deep Water (CDW), which flows below these ice shelves.

Since a majority of the West Antarctic Ice Sheet exists below sea level, it is highly susceptible to this warm water intrusion.

Professor Alberto Naveira Garabato, from the University of Southampton, a co-author of the paper, says: “Our findings suggest a positive feedback loop: as the ice shelf melts more rapidly, more freshwater is produced, leading to a stronger undercurrent and more heat being transported toward the ice shelves.

“This cycle could speed up the melting of ice shelves, potentially making the West Antarctic Ice Sheet less stable in the future."

This study also highlights the in-depth analysis of eastward undercurrents, which transport the warm water to cavities beneath the ice shelves.

Researchers from the University of California Los Angeles, MIT and the University of Southampton used high-resolution simulations to investigate the unknown mechanism driving this undercurrent.

It has been observed that the warm CDW, upon interaction with the ice shelf, melts the ice and mixes with the lighter, melted freshwater. This new water mixture rises and stretches the layer of CDW vertically, in turn creating a swirling water motion.

If a trough (underwater valley) is present near the coast, this swirling motion is driven from the ice shelf cavity towards the shelf edge due to the water's internal pressure movement.

This culmination of events can lead to the formation of a current along the seafloor slope that directs more warm water towards the ice shelf.