A new report warns that rapidly melting Antarctic ice is causing a dramatic slowdown in deep ocean currents and could have a disastrous effect on the climate, according to a team of Australian scientists.
The currents, which carry vital heat, oxygen, carbon, and nutrients around the globe, could decline by 40% by 2050.
Previous research suggests that a slowdown in the North Atlantic current could cause Europe to become colder.
The study, which the journal Nature published, also warns that the slowdown could reduce the ocean’s ability to absorb carbon dioxide from the atmosphere. The report outlines how the downwards movement of cold, dense saltwater towards the sea bed near Antarctica drives the Earth’s network of ocean currents. However, as fresh water from the ice cap melts, sea water becomes less salty and dense, causing the downwards movement to slow.
The effect of “Climate change”
Scientists say that the deep ocean currents, or “overturnings,” in the northern and southern hemispheres have been relatively stable for thousands of years, but the warming climate is now disrupting them.
Study lead Professor Matthew England said, “Our modelling shows that if global carbon emissions continue at the current rate, then the Antarctic overturning will slow by more than 40 per cent in the next 30 years – and on a trajectory that looks headed towards collapse.”
“If the oceans had lungs, this would be one of them,” Prof England, an oceanographer at Sydney’s University of New South Wales, told a news briefing.
Dr Adele Morrison, who contributed to the report, explained that as ocean circulation slows down, water on the surface quickly reaches its carbon-absorbing capacity and is then not replaced by non carbon-saturated water from greater depths.