Scientists are sounding the alarm that a crucial component of the planet’s climate system is in gradual decline and could one day reach a tipping point that would radically alter global weather patterns.

The Atlantic Meridional Overturning Circulation, or AMOC, is a system of ocean currents that circulate water in the Atlantic Ocean like a conveyor belt, helping to redistribute heat and regulate global and regional climates. New research, however, warns that the AMOC is weakening under a warming climate, and could potentially suffer a dangerous and abrupt collapse with worldwide consequences.

“This is bad news for the climate system and humanity,” researchers from Utrecht University’s Institute for Marine and Atmospheric Research wrote in a new study published in the journal Science Advances.