Rotating globe showing sea-surface temperature for 1996 as a colour-coded time sequence with grey terrain-shaded land. The ocean and atmosphere act to reduce temperature differences by transporting heat from the Equator to the poles. Without these heat engines, equatorial regions would be 10degC warmer, and the poles would be 20degC cooler than they are today. At low latitudes it is estimated that up to 74% of poleward heat transport is due to ocean currents.

Data source: NOAA/AHVRR GAC sea surface temperature data processed by NASA Jet Propulsion Laboratory (NASA/JPL)

Credit : Deutsche Forschunzentrum fur Luft- und Raumfahrt