Currents

Without currents the world’s oceans would become stagnant and less conducive to life. Ocean levels would rise, the planet would become less oxygenated and produce more CO ₂ . The world’s climate would become more extreme between the equator and the poles. In fact the world would resemble what it would have been like during the Ice Age.

There are several reasons why currents occur, the main one being the the Coriolis effect.   Also referred to as the Coriolis force, this phenomenon can be observed in the deviation of such objects as aeroplanes, wind or ocean currents moving on a straight course relative to the earth's surface. The strength of the Corilolis effect   is relative to the speed of the earth's rotation at different latitudes and influences moving objects across the globe. Without the Coriolis effect currents would gravitate towards the equator. Up-welling and down-welling of the ocean affects the temperature and density of sea water thus affecting water movement and in effect, the currents.