The ocean and atmosphere are constantly trading heat, and that exchange isn't random, it's structured by currents, wind patterns, and geography. This animation shows the 1979-2025 mean net heat flux at the ocean surface (ORAS5 reanalysis), in W/m². Red means the ocean is gaining heat from the atmosphere; blue means it's losing heat to it. Land is shown in flat gray.

For this globe, the deformation direction is reversed from the earlier ones in this series: the surface sinks where the ocean absorbs heat, and rises where it releases it, gaining pictured as an inward pull, releasing as an outward push. As always, this is a stylistic choice, not a physical measurement.

The clearest features are the western boundary currents: the Gulf Stream and the Kuroshio stand out as sharp blue ridges, the ocean's biggest engines for dumping heat back into the atmosphere, warm water pulled from the tropics and cooled rapidly as it meets colder air at mid-latitudes. By contrast, most of the tropical ocean is a broad red band, patiently absorbing solar heat, which currents like these then export toward the poles.

Data: ORAS5 (ECMWF ocean reanalysis)