There’s a hidden, global network of recycling and reclamation sites that processes the waste we produce.

Most of us recycle. We separate our bottles from our cans, paper from cardboard, and we set it out on the curb to be collected.

But this is just one small step in the recycling process. The role we play in the recycling industry is small at best.

In fact, the recycling industry is dependent on a chain of actors, both large and small, who collect, sort and sell scrap and trash to each other.

The bottom rung is the individual scavenger, such as the panhandler who collects Coke cans from public bins. The products of this labor are then sold, for a profit, to processing and packing institutions such as junkyards and recycling plants. These then sell the bulk objects to companies that melt and transform scrap into new metal, paper and plastic.

The volume of accumulated material increases at each stage in the process – from the panhandler’s few cans to the millions of them sold to manufacturers.

In recent decades, this chain of supply has expanded beyond national borders to the point that, today, waste management takes place within a global logistical network that rivals that of the manufacturing industry: there are scrap metal processors in Southern China that specialize in extracting copper from American Christmas tree lights; there are entire towns in India that manufacture belt buckles from European scrap brass; and there are Chinese scrap dealers who spend half the year touring junkyards in the American South.

But what caused this shift? On the one hand, the migration of manufacturing from the main centers of consumption and, on the other, the advent of cheap transportation options.

Just look at the way in which the waste management industry took advantage of the trade imbalance between China and the United States. Because the US imports more from China than it exports, shipping companies began offering discounts to dealers wanting to ship scrap back to China on container ships that would have otherwise been empty.