A study published Friday warned that a systemic collapse of the Atlantic Ocean currents driving warm water from the tropics toward Europe could be more likely than researchers previously estimated — an event that would send temperatures plummeting in much of the continent.

The Atlantic Meridional Overturning Circulation (AMOC), which includes the Gulf Stream, could be headed for a relatively sudden shutdown that René Van Western, who led the Dutch study published in Science Advances, called “cliff-like.”

For many millennia, the Gulf Stream has carried warm waters from the Gulf of Mexico northward along the eastern North American seaboard and across the Atlantic to Europe. As human-caused global heating melts the Greenland ice sheet, massive quantities of fresh water are released into the North Atlantic, cooling the AMOC — which delivers the bulk of the Gulf Stream’s heat — toward a “tipping point” that could stop the current in its tracks.

An AMOC shutdown would cause temperatures to rise in the Southern Hemisphere […]