The international team, led by Cardiff University researchers, show how southern migration of the westerly winds and the Antarctic Circumpolar Current (ACC) towards the pole during periods of past global warming increased the amount of natural carbon released to the atmosphere by the Southern Ocean.
The team warns that human-induced climate change has brought about a similar process, which is underway today and likely to continue under global warming without appropriate climate action.
Their findings suggest that during particularly warm periods, known as super-interglacials, the mid-latitude ACC slows down, while the flow in the high-latitude Drake Passage, where the Atlantic and Pacific Oceans meet, accelerates.
This indicates a poleward shift in the Southern Hemisphere’s westerly winds, which coincides with a strengthening and similar southward shift of the ACC during warmer climatic conditions.
The team says this southward shift in the ACC and westerly wind systems has massive implications for the way the Southern Ocean absorbs heat and carbon.
Co-author Professor Ian Hall of Cardiff University’s School of Earth and Environmental Sciences, added, “The long-term perspective we gain from paleoclimate data reveals a previously unrecognized connection between the retreat or collapse of the Antarctic Ice Sheet and the reorganization of the ACC.
“This relationship points to important feedback mechanisms that could be activated by the projected retreat of the modern Antarctic Ice Sheet due to human-induced climate change. If the ice sheets continue to recede, we may see further disruptions in ocean circulation, with cascading effects that could impact global climate patterns.”