And so it was that I went from poking in bags of garbage to examining the global systems of production and consumption of manufactured goods, or what academics call the materials economy. That means I cross back and forth between two disciplines that the modern world usually sees as not only sharply divided but at total odds with each other: the environment (or ecology) and the economy. But guess what? Not only are these two systems connected, one is actually a subsystem of the other, the same way that earth's ecosystem is a subsystem of the solar system.
Now, a lot of environmentalists don't really want to deal with the economy. Traditional environmentalists focus on that cuddly endangered bear or the majestic groves of redwoods or the nature preserves where they go to forget all about ugly things like the stock market. Endangered species and pristine places have nothing to do with pricing structures or government subsidies for mining or international trade agreements, do they? (Uh, actually, yes, they do.) Meanwhile, classical economists have acknowledged the environment only as an unlimited and cheap or free set of raw resources to fuel the growth of the economy. Oh, and the arena from which pesky activists sometimes pop up to challenge a new factory site based on protecting the habitat of the woodland shrew.
Yet in fact, the economy is a subsystem of the earth's ecosystem, its biosphere. You see, any economic system—like barter, slavery, feudalism, socialism, or capitalism—is a human invention. Since humans are just one of the earth's many species (albeit a powerful species, what with our written words and our weapons), any invention of ours is a subsystem of the earth's ecosystem. Once we understand that (which is not my opinion, but plain fact), it leads to other insights.
The most important of these further insights is about limits. For one system to exist inside of another, the subsystem needs to fit inside the constraints of the parent system. You've seen those pictures of our pretty blue planet from space, right? The surface area on this hunk of rock that we call home is 197 million square miles (roughly a third of that is land).3 To wrap a (long) piece of string around the middle of the planet at the equator you would need 24,901.55 miles (40,075.16 kilometers) of it.4 The total water supply— in all its states—measures about 326 million cubic miles.5 That's what we've got. The earth's dimensions and capacity remain stable. That means there is a limit to the amount of land, water, air, minerals, and other resources provided by the earth. That's just a fact.
Believe me, I know that can be easy to forget, given the way most of us here in the United States or in other rich nations live. How would we know that the soil is degrading or the oceans are being emptied of fish? Few of us get to see our food growing or the nets pulling our fish out of the water. Let alone where and how our T-shirts, laptops, books, and other Stuff is made, halfway across the planet. From where I sit in my cozy Berkeley bungalow, the world looks pretty good: the weather's nice, the vast selection in the grocery store is undiminished by the fact that my state of California is in a multiyear drought. If our fruit harvest is low this year, apples still arrive from Chile. Don't worry, be happy.