Major ocean current?

Question

What are major ocean current?

Which oceans are cold and which coeans are warm and why Are these oceans cold or warm?

Do Currents affect weather?

Why these oceans and ocean current are important?

Answer 1

Major ocean currents of the world include (please see illustration for a more complete listing):

North & South Equatorial Current

Equatorial Counter Current

North Atlantic Drift

Gulf Stream

Kuroshio Current (off of Japan)

Antarctic Circumpolar Current

East Australian current

There are two main sections of ocean water: the surface layer and the the deep waters. The surface layer is the layer at the top of the ocean that is well mixed by waves, tides, and weather events like rain or a hurricane. The surface layer sits on top of the deep water because the surface layer is less dense. The depth of the surface layer varies depending on location and season, but the depth is typically a couple hundred meters. There is a boundary layer between the surface layer and the deep waters that is called the the pycnocline (meaning rapid change of density). The pycnocline is caused by rapid changes of temperature and salinity.

Surface water movement takes place in the form of currents. Currents move ocean water horizontally at the ocean's surface. Surface currents are driven mainly by the wind. Other forces such as the Coriolis effect and the location of land masses do affect surface current patterns. In fact, huge circular patterns called current gyres can be seen when looking at the world's ocean currents. From the equator to middle latitudes, the circular motion is clockwise in the Northern Hemisphere and counterclockwise in the Southern hemisphere. Near the poles of the Earth, there is a tendency for the gyres to flow in the opposite direction. This circulation of water helps spread energy from the Sun. The Sun warms water at the equator and then water and heat are transported to higher latitudes.

Ocean currents do affect the weather.  One of the most important to the USA and western Europe is the Gulf Stream.  

The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates in the Gulf of Mexico, exits through the Strait of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean. At about 30°W, 40°N, it splits in two, with the northern stream crossing to northern Europe and the southern stream recirculating off West Africa. The Gulf Stream influences the climate of the east coast of North America from Florida to Newfoundland, and the west coast of Europe. It is part of the North Atlantic Subtropical Gyre.

Computer climate models show that if fresh water is added to sensitive locales in the North Atlantic Ocean, it would increase surface water buoyancy enough to brake the overturning circulation, and less warm water and heat would flow northward. Nothing like the changes predicted by computer models has ever been seen during the brief interval of modern studies of the sea. So to evaluate the possibilities, scientists must extend oceanography back in time, long before recorded human history, to reveal the full range of possible ocean circulation changes and their impacts on climate.

The ice caps and glaciers are melting at a rate unprecedented in modern times.  This fresh water diluting the Gulf Stream may cause it to shut down.  This will result in most of the USA and Europe being too cold to be habitable or to grow crops in.  That will leave us no place to go but south.  How is Mexico going to react to that considering that we are persecuting illegal aliens from Mexico and building the new "Berlin Wall".