The Great Pacific Garbage Patch is considered by some scientists to be a misnomer for the floating pile of garbage approximately the size of Texas which can be found between Oregon and the Hawaiian Islands, since it suggests that the epic amount of garbage may be manageable. Whatever it is called, the Great Pacific Garbage Patch represents an environmental disaster for the world's oceans, and it is often used to illustrate the need for conservation policies which take the ocean into account. When it was sampled in 2001, the Great Pacific Garbage Patch yielded six pounds (three kilograms) of plastic for every pound (half kilogram) of plankton in the water.

The garbage patch formed and continues to exist because of ocean currents. The patch is not actually static in position, sometimes drifting into landmasses which have begun to resemble landfills. It moves with the North Pacific Subtropical Gyre, a high pressure zone of air which forces ocean surface currents to move in a slowly clockwise pattern, creating a whirlpool which sucks garbage from other parts of the ocean into the gyre. The high pressure zone is extremely stable, as it is caused by hot air from the equator cooling as it moves northwards. There are several such gyres around the world, and they are traditionally avoided by sailors and fishermen because they are devoid of wind and marine organisms.

The traditional avoidance of the North Pacific Subtropical Gyre meant that the garbage slowly collecting there had accumulated immense volume by the time it began to be recognized. Most of the debris in the Great Pacific Garbage Patch is made from plastic, which does not biodegrade. Organic material and debris from other sources will eventually break down, but plastics do not, although they do break into smaller and smaller pieces. Greenpeace estimated that approximately 10% of the plastics manufactured every year ultimately end up in the Great Pacific Garbage Patch.

The environmental risks posed by the Great Pacific Garbage Patch are manifold. To begin with, the area supports minimal marine life, because the garbage patch restricts the limited area of water which photosynthetic organisms can live in. Other marine life including birds, mammals, fish, and jellyfish also suffer because they mistake the garbage for food. The garbage also carries a hidden payload: oily toxins which have accumulated in the plastic floating on the surface of the Great Pacific Garbage Patch. These toxins appear to be absorbed and concentrated by the plastics, which are in turn eaten by unwitting animals.

Public awareness about the Great Pacific Garbage Patch was increased in 2006, when a number of feature news articles on the subject were published. Some scientists fear that increased knowledge about the issue may be coming too late, as cleanup of the Great Pacific Garbage Patch may be impossible. The issue does highlight the growing problem of garbage in the world's oceans, and it is hoped that awareness will drive consumers to reduce the amount of garbage they generate, as well as spurring international cooperation to address the problem.