The Atlantic Meridional Overturning Circulation, or AMOC for short, is the large-scale flow of water -- driven by temperature and salinity gradients -- specific to the Atlantic Ocean. Researchers say they've located signs that it and other portions of Earth's oceanic conveyor belt are slowing.

The global conveyor belt doesn't just move water, it moves heat too -- delivering it (in the case of the AMOC) from the tropics and the Southern Hemisphere to the North Atlantic. It is a vital component of climate as we know it. Should it continue to slow and become disrupted, it could spell drastic and abrupt climate change.

New climate models developed by scientists at the University of Exeter, in England, suggest a major disruption of the AOMC could present warning signs as many as 250 year prior; and now researchers say they're seeing those warning signs in real life.

"We found that natural fluctuations in the circulation were getting longer-lived as the collapse was approached, a phenomenon known as critical slowing down," lead author Chris Boulton, a geography professor at Exeter, said in a press release.

Boulton and his colleagues say the continued influx of freshwater, driven by global warming and the melting polar ice caps, could be enough to slow AMOC to a halt. A collapse of the ocean conveyor belt would mean drastic cooling in northern climes, rising sea levels, and prolonged drought conditions in some areas.

"We don't know how close we are to a collapse of the circulation, but a real world early warning could help us prevent it, or at least prepare for the consequences," co-author Professor Tim Lenton said.

The research was published this week in the journal Nature Communications.