"The Atlantic Ocean’s sensitive circulation system has become slower and less resilient, according to a new analysis of 150 years of temperature data — raising the possibility that this crucial element of the climate system could collapse within the next few decades.

Scientists have long seen the Atlantic Meridional Overturning Circulation, or AMOC, as one of the planet’s most vulnerable “tipping elements” — meaning the system could undergo an abrupt and irreversible change, with dramatic consequences for the rest of the globe. Under Earth’s current climate, this aquatic conveyor belt transports warm, salty water from the tropics to the North Atlantic, and then sends colder water back south along the ocean floor. But as rising global temperatures melt Arctic ice, the resulting influx of cold freshwater has thrown a wrench in the system — and could shut it down entirely.

The study published Tuesday in the journal Nature Communications suggests that continued warming will push the AMOC over its “tipping point” around the middle of this century. The shift would be as abrupt and irreversible as turning off a light switch, and it could lead to dramatic changes in weather on either side of the Atlantic."

Sarah Kaplan reports for the Washington Post July 25, 2023. [2]