Climatology

North Atlantic Deep Water

Ocean current

Thermohaline circulation

Shutdown of thermohaline circulation

Computer science

Circulation (fluid dynamics)

Geology

Current (fluid)

Oceanography

Thermodynamics

Physics

Proxy (statistics)

Mechanics

Machine learning

Zonal and meridional

Nature Geoscience

The Atlantic Meridional Overturning Circulation (AMOC)—one of Earth’s major ocean circulation systems—redistributes heat on our planet and has a major impact on climate. Here, we compare a variety of published proxy records to reconstruct the evolution of the AMOC since about ad 400. A fairly consistent picture of the AMOC emerges: after a long and relatively stable period, there was an initial weakening starting in the nineteenth century, followed by a second, more rapid, decline in the mid-twentieth century, leading to the weakest state of the AMOC occurring in recent decades. The Atlantic Meridional Overturning Circulation (AMOC) is currently distinctly weaker than it has been for the last millennium, according to a synthesis of proxy records derived from a range of techniques.

Current Atlantic Meridional Overturning Circulation weakest in last millennium