Climate change may be slowing down deep ocean currents

Deep ocean currents act as conveyer belts, channeling heat, carbon, oxygen and nutrients around the globe.

A new study by the University of Pennsylvania's Irina Marinov and Raffaele Bernardello and colleagues from McGill University has found that recent climate change may be acting to slow down one of these conveyer belts, with potentially serious consequences for the future of the planet's climate.

"Our observations are showing us that there is less formation of these deep waters near Antarctica," Marinov said.

"This is worrisome because, if this is the case, we're likely going to see less uptake of human produced, or anthropogenic, heat and carbon dioxide by the ocean, making this a positive feedback loop for climate change," she said.

Oceanographers have noticed that Antarctic Bottom Waters, a massive current of cold, salty and dense water that flows 2,000 meters under the ocean's surface from near the Antarctic coast toward the equator has been shrinking in recent decades.

This is cause for concern, as the current is believed to "hide" heat and carbon from the atmosphere. The Southern Ocean takes up approximately 60 percent of the anthropogenic heat produced on Earth and 40 to 50 percent of the anthropogenic carbon dioxide.

Along with colleagues, Marinov used models to discern whether the shrinking of the Antarctic Bottom Waters could be attributed to anthropogenic climate change.

The study is published in Nature Climate Change.