What Does “Sustainable” Mean?

It’s the new talisman of the 21st century. Every architect, every beverage bottler, every timber grower, every strip miner, wants you to believe that he, she, or it is “sustainable” or using “sustainable practices.” What do they mean, and what are we entitled to expect when someone uses the term?

Our dictionary defines “sustainable” as “capable of being sustained” or “capable of being continued with minimal long-term effect on the environment:” For how long? Well, one would think, indefinitely.

So if I wish to defend my practice as “sustainable,” I should be willing to show you how it can continue indefinitely with little or no impact on the earth’s environment. I should be able to show you how I can keep doing what I’m doing, growing at the same rate I’m now growing, for some meaningful period of time, say 500 years, with little or no effect on the environment. If I can’t, then you have a right to question whether I should be calling what I do “sustainable.”

And this calls into question the whole question of economic growth. Is economic growth ever sustainable?

According to Richard Heinberg’s Oil Depletion Protocol, any practice, any process, that we call sustainable on a global scale (which, after all, is the only scale that really matters), should pass two litmus tests, one with respect to its use of renewable resources, and the other with respect to its use of nonrenewable resources.

  1. We should be using renewable resources (things like fresh water, fish in the sea, wood from forests, and topsoil) at a rate that is lower than or equal to the rate at which those resources are naturally replenished. So we should be harvesting fish from the ocean no faster than those fish spawn and mature in the ocean. We could verify this easily by random sampling techniques. We are using those techniques now to disclose that we are far from sustainability.
  2. We should be using nonrenewable resources (things like metals, coal, petroleum, and uranium) at a rate that declines faster than the rate of depletion. That is, we measure and publish the total global supply of a resource, like petroleum, for example. Then we measure our annual extraction as a percentage of that total supply. That is our rate of depletion. So let’s say we determine that we are using 4% of the world’s supply annually. Then to be sustainable, our use of that resource should be declining each year by at least 4%.

Finally, beware of a recent trend toward confusing the term “renewable” with “sustainable.” They’re not the same, but you are surrounded by those who want you to merge them in your mind.