Heat, Oceans, and Climate

Ocean currents move in response to global wind patterns and Earth's rotation. Uneven heating of Earth creates global winds that form three separate bands in each of the northern and southern hemispheres. Earth receives more solar radiation at the equator than it does at the poles, and this uneven distribution of heat creates pressure differences, which in turn cause the movement of air, or wind. Earth's rotation causes fluids — both air and water — to be deflected as they move across our planet's surface. This is known as the Coriolis effect. The Coriolis effect causes winds to move in an eastward or westward direction in addition to their northward or southward flow.

One important ocean current in terms of climate is the Gulf Stream. Without the Gulf Stream, Londoners might expect their winters to resemble those in Calgary, Alberta. At 60 degrees north latitude, the west coast of Norway should look very much like Siberia in January. Instead, the Gulf Stream delivers a steady flow of heat to the atmosphere near the North Atlantic. As a result, London sees plenty of rain but very little snow. And the west coast of Norway remains ice-free all winter, not at all like Northern Saskatchewan or Siberia. The following video explains how the Gulf Stream is created and its role in global climate.



Source: Teachers' Domain, What Causes the Gulf Stream?, published December 17, 2005, retrieved on February 11, 2010, http://www.teachersdomain.org/resource/ess05.sci.ess.watcyc.gulfstream/