To this day, nature hasn’t come up with a microbe that eats it [a tire], either. Goodyear’s process, called vulcanization, ties long rubber polymer chains together with short strands of sulfur atoms, actually transforming them into a single giant molecule. Once rubber is vulcanized — meaning it’s heated, spiled with sulfur, and poured into a mold, such as one shaped like a truck tire — the resulting huge molecule takes that form and never relinquishes it.
Being a single molecule, a tire can’t be melted down or turned into something else. Unless physically shredded or worn down by 60,000 miles of friction, both entailing significant energy, it remains round. Tires drive landfill operators crazy, because when buried, they encircle a doughnut-shaped air bubble that wants to rise. Most garbage dumps no longer accept them, but for hundreds of years into the future, old tires will inexorably work their way to the surface of forgotten landfills, fill with rainwater, and begin breeding mosquitoes again.
In the United Sates, an average of one tire per citizen is discarded annually — that’s a third of a billion, just in one year.