We often think that the oceans are stagnant without strong undercurrents. It is a wrong notion! The water in the oceans does move about and has a regular pattern of movement. The movement of the ocean water in certain directions due to various causes is known as ocean currents.
What moves ocean water? The rotation of the moon around the earth is the major force behind ocean currents. There are circular currents in the north and south of the Pacific and Atlantic oceans. Another key current travels around Antarctica.
Ocean currents affect climate. The oceans have warm and cold surface currents that act like a global heating and air conditioning system. For example, the Gulf Stream in the North Atlantic Ocean carries warm salty water from the equator up to the coast of Greenland in the Arctic. This water travels near the surface of the ocean. As it travels to the Arctic, the warm water heats the countries of the North Atlantic, like Britain. It then cools down, thus increasing the density of water. The dense water sinks to the bottom, where it is carried back to the equator.
Global warming is making the ice caps melt, and they will flow into the ocean, and dilute the salty equatorial water. This will make it less dense, and stop it from sinking. In this way, global warming could stop ocean currents, causing drastic climate changes.
Picture Credit : Google