The Atlantic Meridional Overturning Circulation (AMOC) is a deep sea system that circulates warm water and helps to regulate Earth’s climate. New studies have concluded that the system is far less stable than scientists once thought.

Under climate change pressures, such as the dramatic increases in atmospheric carbon dioxide (CO2), the AMOC could even collapse entirely, resulting in a much colder Northern Hemisphere and a wetter tropical Atlantic region.

However, computer models used to predict Earth’s climate future, typically represent AMOC as relatively stable. An unstable AMOC as described in the study changes the equation in which the current weakens and ultimately fails to recover from repeated disruption with dire consequences for the global climate.

AMOC operates like a gigantic conveyor belt in the depths of the Atlantic Ocean, with cold dense waters carried southward towards the equator. At the same time closer to the surface, the current transports heat (in the form of less warm dense water) from the tropics to the North, where it gets transferred into the atmosphere and warms the air.

According to the National Ocean and Atmospheric Administration (NOAA), this heat exchange is what drives and maintains global climate patterns.

Though the study used only one computer model and one global warming scenario, its findings suggest that allowing for an unstable ocean current produces vastly different outcomes, presenting “enormous implications” for climate change on a regional and global level.

NOAA / Crickey Conservation Society.

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