What do we do with old tires?

You are in charge of recommending to the Environmental Protection Agency how best to recycle old tires. Tire piles like this one these can put enormous stresses on the environment. New uses for scrap tires ease demand for Earth's natural resources and save energy.

How many tires do you think get thrown away every year world wide? A million? 5 million? 10 million?

Why do you think tires piles like this are bad for the environment?