Introduction | Energy | Water | Atmosphere | Ocean | Carbon | Nitrogen | Rock

The Ocean in Motion

The ocean water is in motion because of differences in temperature and saltiness. Water that is warmed at the sea surface near the equator moves toward the chilly poles. Cold, salty currents flow into the deepest parts of the sea.

Oceans can hold a large amount of heat energy – much more than the atmosphere. In the past few decades, Earth’s oceans have become warmer. Even as far as 2 miles (3.2 kilometers) below the surface of the sea, the ocean water has been warmed. Scientists estimate the oceans may have absorbed up to half of the energy trapped by greenhouse gases over the last century.