The waters surrounding Antarctica have stayed at roughly the same temperatures while the seas in other parts of the world have been slowly warming.
Science has a new solution to the question of why these southern waters may be one of the last places to be affected by climate change.
Research from the University of Washington and the Massachusetts Institute of Technology shows that currents around Antarctica continually pull deep, centuries-old water to the surface.
This seawater last touched Earth’s atmosphere before the machine age and has never experienced fossil fuel-related climate change.
“With rising carbon dioxide you would expect more warming at both poles, but we only see it at one of the poles, so something else must be going on,” says Kyle Armour, a University of Washington assistant professor of oceanography and atmospheric sciences.
“We show that it’s for really simple reasons, and ocean currents are the hero here.”
Gale-force westerly winds act to push surface water north from Antarctica, continually drawing up water from below.
The Southern Ocean’s water comes from such great depths, that it will take centuries before the water reaching the surface has experienced modern global warming.
Along the west coast of the Americas and the equator, seawater is drawn up from just a few hundred meters depth.
“The Southern Ocean is unique because it’s bringing water up from several thousand metres,” says Armour. “It’s really deep, old water that’s coming up to the surface, all around the continent. You have a lot of water coming to the surface, and that water hasn’t seen the atmosphere for hundreds of years.”
The research findings are published in the journal Nature Geoscience.
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