The team has been using remotely-operated gliders to confirm previous research which pointed to warm sea currents, rather than warmer air temperatures, being responsible for melting the ice. Scientists have been working in the Weddell Sea in West Antarctica.
“What we’re looking at is delivery of heat right up to the ice shelf, where the ocean touches up against the ice,” said lead scientist Andrew Thompson, a physical oceanographer at Caltech. “It’s almost like a blob of warm water, a little ocean storm.”
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Robot gliders confirming previous suspicions
According to a report in the journal Nature Geoscience, the robot gliders have discovered swirling eddies which push warm water right up to the floating platforms of ice where glaciers enter the sea. Previous studies of the West Antarctic have shown evidence that melting of the ice sheet may be irreversible, and if it were to completely melt then sea levels could rise by up to 10 feet.
The gliders do not use propellers, but rather use a pump to fill a bladder with water to change their buoyancy, surfacing to upload collected data via a satellite phone network. They collected temperature and salinity data from the upper 0.6 miles of the ocean over the course of two months.
Further research necessary
The latest report marks the first time that scientists have explained how warm water rises from the depths to reach the ice. Further research is needed to work out the effects of this heat reaching the grounding line, where glaciers meet the ocean, which is where most melting takes place.
Antarctica is surrounded by layers of cold and warm water, with a differentiation of just a few degrees enough to melt a glacier. Warmer water sits in the middle layer of the ocean after being carried from the north by a current known as the global conveyor belt. It sits below a layer of colder surface water formed by cold winds blowing over the ocean.
Research into the effects of currents on these layers is crucial to improving our understanding of melting ice shelves, and hopefully arresting the process before a catastrophic rise in sea levels.