New climate modelling shows that a collapse of the Atlantic Meridional Overturning Circulation could release up to six hundred and forty billion metric tons of carbon dioxide from the Southern Ocean near Antarctica. This would add around zero point two degrees Celsius of extra warming to global temperatures. The Atlantic Meridional Overturning Circulation, which includes the Gulf Stream, is already at its weakest level in over one thousand years. Scientists warn the finding strengthens the urgent case for deep, rapid cuts in global carbon emissions.