Ancient seafloor sediments have revealed a surprising twist in how the Atlantic’s massive circulation system works. During a cold period about 3.4 million years ago, the flow of warm, salty water from the Indian Ocean into the Atlantic nearly shut down—but the AMOC did not weaken as expected. Parts of the overturning circulation actually grew stronger.

Ancient seafloor sediments have revealed a surprising twist in how the Atlantic’s massive circulation system works. During a cold period about 3.4 million years ago, the flow of…

Scientists have found that the AMOC may be far more vulnerable to rapid warming than to temperature alone. When warming happens slowly, the ocean can adapt, but at faster rates…