How did this happen?

An image of the North Pacific Gyre and the currents that created "The Garbage Patch"

Urban and industrial runoff is a main source of marine pollution. Here a factory disposes of its wastes in a local body of water

Shipping pollution is a point source that usually is directly disposed into ocean waters as shown above.

The ocean, a world of beauty and mystery, has become very tainted by the actions of mankind. All over the world people have grown into habits that have been discovered to have severe consequences on the ocean. In a world dominated by money and making profit, people have seemed to always try to find the easy way of doing things, particularly disposing of their wastes. In some cases, marine pollution occurs by chance, but in most cases it is the result of laziness and an overall lack of consideration.

Marine pollution comes from multiple sources. The sources are usually separated into two different categories, point sources and non-point sources. Point source pollution occurs when there is a single, identifiable source of the pollution. Examples of this would be the direct discharge of sewage, shipping and  industrial waste or even polluted storm drains which is often the case in urban areas. Non-point source pollution occurs when the pollution is diffused or the location of the pollution entry is unidentifiable. Prime examples of this would be agricultural runoff and wind blown debris.

Once the pollution has been exposed to the ocean it enters oceanic currents known as "horse latitudes." These currents move in a rotational pattern in the North Pacific Ocean known as the North Pacific Gyre. As the polluted currents rotate, wind-driven surface currents push this debris towards the stagnant waters in the center of the gyre where it remains trapped creating "The Garbage Patch."