A new study published in the journal Science Advances warns that a critical system of Atlantic Ocean currents is “on course” to a tipping point that would dramatically impact global temperatures and sea levels.
The Atlantic meridional overturning circulation (AMOC) effectively transports heat and salt through the global ocean and strongly modulates regional and global climate, the study explains.
It is part of the thermohaline circulation, otherwise known as the “great ocean conveyor belt,” a system of currents that circulate throughout the oceans and is driven by temperature and salinity. It plays a key role in distributing heat and energy.
Further, from proxy records, it is suggested that the AMOC is currently in its weakest state in over a millennium.
The study used a supercomputer to run climate models, whereby scientists simulated the gradual increase of freshwater to the AMOC over a period of years, a simulation that has not been conducted before with a complex global climate model (GCM).
It found that the gradual increase of freshwater, for example, from river runoff from swelling, increased rainfall or ice melt, could result in an abrupt AMOC collapse.
The researchers said that this provided a “clear answer” that an abrupt shift is possible.
“This is bad news for the climate system and humanity as up till now one could think that Amoc tipping was only a theoretical concept and tipping would disappear as soon as the full climate system, with all its additional feedbacks, was considered,” the study said.
The tipping point, it was shared, could result in extreme weather in the Northern Hemisphere and significantly disrupt rainfall, with the southern hemisphere witnessing accelerated warming. There could also be a 100cm rise in European sea levels.
Read the full study here.