If you were to sail due west from San Francisco, California, after about 2000km you would find yourself in a very strange place. This is an area of the Pacific Ocean technically referred to as the North Pacific Gyre, but a more descriptive term is the Great Pacific Garbage Patch. You heard correct. Decades of constant oceanic currents have resulted in a huge area of the Pacific that has become a veritable black hole of human-produced waste. 

Oceanic currents are largely steady over the period of centuries. Since the days of colonisation, Christopher Columbus and his friends had capitalised on reliable trade winds to propel them to and from the Americas. Within these swirling, connected currents lie a few select dead spots, where the motion of the ocean is effectively nil. There are five of these so-called gyres located throughout the world.

The Floating Island of Garbage was discovered surprisingly recently. The story goes, a sailor named Charles Moore was returning to Los Angles after competing in a race. Normally, seamen avoid the North Parasitic Gyre like the plague. The absence of wind makes sailing impossible, and the dearth of large critters renders the area unprofitable for fishing. 

On this one particular occasion in 1997, Charles Moore had a little extra time, and an outboard motor on his sailboat. He decided to take a shortcut and cross through the normally-avoided area of the sea. What he saw was astounding: plastic, plastic everywhere. Moore would later return to the area to conduct thorough investigations to quantify the extent of the mess. 

The actual size and trash-density of the garbage patch is somewhat debatable. The general consensus is that it is around the size of the continental US and contains floating bits of plastic that are more concentrated than plankton in some areas. While the statistics are staggering, this description may paint an inaccurate picture. The mental image I first saw was a solid layer of bags, a few meters thick, that you could walk across. While I couldn't find a decent picture of it, in reality the garbage patch is not any sort of solid surface. 

Aside from just the mess, more disconcerting is that the plastic is starting to work its way into the food chain. For years, chemists have sought to make increasingly robust plastics, and they have succeeded. If you were to go out and buy a bag of frozen lima beans, it would likely stay fresh for quite a while. 

The downside is after you eat those lima beans, the discarded bag will stay on this planet longer than you will. Polyvinylchloride, polyethylene, etc, cannot be degraded by any normal organism. Sitting out in the Pacific, baking in the sun, these polymers undergo photodegradation instead. Sunlight breaks down polymers into smaller and smaller pieces, until they get to be so small that even microscopic plankton will eat them. When the bottom of the food chain starts to eat our garbage, it's just a matter of time before it works its way into fish, birds, and eventually onto our dinner plates. If the Floating Island of Garbage is left unchecked, eventually those frozen lima beans will contain parts of the bags they come in. 

Because the island was discovered only recently, it has become far too large to even consider cleaning up. Compare and contrast with another environmental disaster: the Exxon Valdez oil spill in 1989. There, the spill covered a mere 28 000km2 of the ocean's surface (about 100 times smaller than the garbage patch), and cost about £1 billion or so to clean up.There has been an interest within the chemical community to make polymers that are at least somewhat biodegradable. There hasn't been a major success so far, one reason being that some of the materials are a little too biodegradable. That is, you don't want a bottle of orange juice to dissolve before you get the chance to drink it. So there's no good solution for what to do about the garbage island, other than trying not to make it worse. I won't even try to evaluate the global political and economic changes that would be needed for that. But I can say for sure that next time I'm at the shop, I'll bring my own canvas bag.