By Neal Lineback and Mandy Lineback Gritzner, Geography in the NewsTM
The Great Swirling Pacific Garbage Patch
Ocean pollution is growing at an astonishing rate.
On June 1, 2008, two scientists and a photographer/blogger sailed from Long Beach, California, and headed westward across the Pacific Ocean to Hawaii. The two men and a woman were not traveling on any luxury cruise liner. They were sailing on the JUNK, a boat created from 15,000 plastic bottles and the fuselage of a Cessna 310 airplane. The group successfully raised awareness about plastics that are fouling the world’s oceans.
As the JUNK sailed across the ocean, it ventured into the “Great Pacific Garbage Patch,” areas of the Pacific that are continent-sized vortexes of swirling garbage, mostly plastics. This “plastic soup” has been growing recently at an alarming rate and scientists now estimate that it covers an area more than twice the size of the continental United States. The plastics and other trash are up to 33 feet (10 m) thick in some areas.
The “soup” stretches from about 500 nautical miles off the coast of California, across the northern Pacific, past Hawaii and almost as far as Japan. The clockwise swirling ocean currents in the Pacific subtropical gyre tend to hold the garbage together, sometimes in one or two dense concentrations depending on the changing seasonal wind patterns and storms.
An ocean current is a horizontal movement of seawater at the ocean’s surface. Circulating winds above surface waters drive ocean currents. Friction, which occurs at the interface between the ocean and the wind, moves the water in the direction of the wind. Some currents are fleeting features affecting only a small area. Other ocean currents are more permanent and extend over vast distances.
Globally, the continental landmasses surrounding the three major oceanic basins constrain the large ocean currents of the world. These continental borders cause these currents to develop large circular patterns of flow called a gyres.
All of Earth’s major oceans contain subtropical gyres located at approximately 30 degrees north and south latitude. The subtropical high-pressure systems operating in these regions drive the currents in these gyres. These circulations rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
Researchers estimate that the Pacific gyre contains at least 100 million tons of garbage. According to a newspaper article in London’s The Independent, the garbage includes everything from footballs and kayaks to Lego blocks and plastic grocery bags. An estimated one-fifth of the junk comes from ships or oil platforms. The rest comes from land, carried by rivers or sewage systems and storm drains that have overflowed.
The problem in the “Great Pacific Garbage Patch” is that historically the rubbish that made it out to sea would biodegrade. However, modern-day plastics are so durable that the gyres contain some 50-year old plastics—the plastics do not break down for years. Because the plastics are mostly translucent, satellite photos are unable to record the vortex of the garbage islands. They can be seen clearly, however, from the bow of a ship.
The United Nations Environment Programme says that plastic debris causes the deaths of more than a million seabirds every year, as well as perhaps 100,000 marine mammals. The animals mistake the plastics for food and die trying to digest them. All manners of plastics are found inside the carcasses of dead and dying marine birds. Other marine scientists say that the evidence is not complete.
According to Dr. Marcus Eriksen, one of the researchers who sailed on the JUNK, the rubbish also poses a risk to humans. Tiny plastic pellets, or nurdles, the raw materials comprising plastics, are lost or spilled each year. Many of these make their way into the oceans. These pollutants behave as chemical sponges, attracting synthetic chemicals like hydrocarbons and the pesticide DDT. As fish ingest the tiny polluted particles, they become contaminated. When humans eat the fish, they also ingest the chemicals.
Scientists believe that 90 percent of all trash floating in the oceans is plastic. The U.N. Environment Programme estimated in 2006 that every square mile (1.6 km) of ocean contains 46,000 pieces of floating plastic.
With 40 percent of the world’s oceans as subtropical gyres, plastics may already cover almost a quarter of the oceans’ surface area. This is a huge environmental issue with major geographic implications and no permanent solutions in sight.
And that is Geography in the News.
Sources: GITN 950 “The Great Pacific Garbage Patch,” Maps.com, Aug. 20, 2008; http://www.independent.co.uk/environment/the-worlds-rubbish-dump-a-garbage-tip-that-stretches-from-hawaii-to-japan-778016.html; http://www.mindfully.org/Plastic/Ocean/Moore-Trashed-PacificNov03.htm; and http://www.nytimes.com/2008/06/22/magazine/22Plastics-t.html?_r=1&partner=rssnyt&emc=rss&oref=slogin
Co-authors are Neal Lineback, Appalachian State University Professor Emeritus of Geography, and Geographer Mandy Lineback Gritzner. University News Director Jane Nicholson serves as technical editor. Geography in the NewsTM is solely owned and operated by Neal Lineback for the purpose of providing geographic education to readers worldwide.