Surface warming-induced global acceleration of upper ocean currents

How the ocean circulation changes in a warming climate is an important but poorly understood problem. Using a global ocean model, we decompose the problem into distinct responses to changes in sea surface temperature, salinity, and wind. Our results show that the surface warming effect, a robust feature of anthropogenic climate change, dominates and accelerates the upper ocean currents in 77% of the global ocean. Specifically, the increased vertical stratification intensifies the upper subtropical gyres and equatorial currents by shoaling these systems, while the differential warming between the Southern Ocean upwelling zone and the region to the north accelerates surface zonal currents in the Southern Ocean. In comparison, the wind stress and surface salinity changes affect regional current systems. Our study points a way forward for investigating ocean circulation change and evaluating the uncertainty.

Automated summary

The changes in ocean circulation in a warming climate are poorly understood but important. Using a global ocean model, this study explores the distinct responses of ocean circulation to changes in sea surface temperature, salinity, and wind. The results reveal that the surface warming effect dominates and accelerates upper ocean currents globally, while wind stress and surface salinity changes affect regional current systems.