Thoughts on Plastic
Here is Africa, as in many parts of the world, most trash is just thrown out onto the road, the street, or wherever. My neighborhood is no exception, but most people here actually carry their garbage around the block and dump it in the ditch in front of a vacant lot (conveniently located across from a primary school). There are a lot of animals wandering around, so goats, chickens, dogs, cats, pigs, guinea fowl, and all manner of lizards and insects eat the organic material. However, the rest of the garbage either gets burned periodically or just sits there. Paper and metal will decompose within a few years here, but plastics last a long time.
Fortunately, people here are big on reusing things. For example, yesterday I bought baking soda packaged in cardboard boxes originally used to sell lantern wicks. So the relatively few glass and plastic bottles tend to get reused over and over. Of course you still have to be careful that you are not buying cooking supplies out of a container recently used to hold insecticide or drain cleaner. Beer and soda in bottles are much cheaper, because the bottles are used over and over. For example, the contents of a glass bottle of soda is 250F, but a smaller plastic bottle is 450F.
Unfortunately, one of the most ubiquitous and obnoxious forms of trash here is the black plastic sachet (bag). Everyone uses these, and it is hard to go the market without using at least half a dozen of them (I bring mine with me to reuse, but most people do not). The owner will then (usually the same day) jeter the sachet which will be blown away, dumped in a ditch, filled with something gross, or swept into a pile of other trash. There may be many kinds of trash in the trash pile, but the things that accumulate are plastic bags.
As I puttered around this morning, I wondered what will happen to all this material as it eventually photo-degrades. Plastic bags exposed to sun and wind will eventually turn into smaller and smaller pieces of plastic. In many respects this stuff resembles some perverse kind of man-made sand—another ubiquitous biologically inert material.
What would an alien geologist think of the current period of Earth history in a few million years? Maybe the geologist will treat the disposable use of plastics over 100 years or 500 years as a pseudo-geologic event, like a volcanic eruption or a tsunami. It distributes a layer of this stuff all over the world, much like a layer of ash, but more permanently.
