What is “Sustainability”?

Posted by Don Fullerton on May 4, 2012

Filed Under (Environmental Policy, Finance, Retirement Policy, U.S. Fiscal Policy)

My own research area is environmental and natural resource economics, which others often call “sustainability”.  That’s actually embarrassing, because I don’t know what it means.  For a renewable resource like timber, it seems pretty easy:  you just plant trees, let them grow, cut them down, and then plant trees again.  For a nonrenewable resource like oil, it’s impossible: once a barrel of oil is consumed, it’s gone forever.  The only way to make oil “sustainable” is not to use it, which does not make any sense, because oil has no value at all if it can’t be used.

So, sustainability is either obvious or impossible.  The concept seems to be of no use whatever.  So I turn to people smarter than me, to get some answers.  By “smarter than me”, in this case, I mean (1.) Nobel-Prize winning economist Robert Solow, and (2.) whoever writes for Wikipedia.

Way back in 1991, Robert Solow wrote “Sustainability: An Economist’s Perspective”, in which he says:  “It is very hard to be against sustainability. In fact, the less you know about it, the better it sounds.”   He says he has seen various definitions, but they all turn out to be vague.  So his essay is an attempt to make it more precise.  “Pretty clearly the notion of sustainability is about … a moral obligation that we are supposed to have for future generations.”   But you can’t be morally obligated to do something that is not feasible!  He notes UNESCO’s definition:  “… every generation should leave water, air, and soil resources as pure and unpolluted as when it came on earth.”   But taken literally, that injunction “would mean to make no use of mineral resources; it would mean to do no permanent construction, … build no roads, build no dams, build no piers.”  That is neither feasible nor desirable!

Instead, he suggests that sustainability might be both feasible and desirable if it is defined as “an obligation to conduct ourselves so that we leave to the future the option or the capacity to be as well off as we are.”   In the final analysis, what that means is that we don’t necessarily have to leave all the oil in the ground, if we leave something else of equal or greater value, some other investment that can be used by future generations to produce and consume as we do, and which they can leave to other generations after them.  It is a holistic concept, both simple and operational.  We only need to add the value of all assets, subtract all liabilities, and make sure that the net wealth we bequeath is not less than we inherited. 

We can use oil, but we should not simultaneously be running huge government budget deficits that reduce the net wealth left to our children and their children.  The measure of “net wealth” should include the value of ecosystems, fresh water supplies, biodiversity, and oil, as well as productive farmland, infrastructure, machinery, and other productive assets.   All those values are extremely difficult to measure, but at least the concept is clear.

Has that message been adopted since 1991?  It certainly does not seem to be part of the thinking of the U.S. Congress and the rest of our political system.   What are they using for guidance?

Wikipedia says  “Sustainability is the capacity to endure. For humans, sustainability is the long-term maintenance of responsibility, which has environmental, economic, and social dimensions, and encompasses the concept of stewardship, the responsible management of resource use.”  Okay, well, that’s still pretty vague, by Solow’s standards.  Let’s see if they make it more specific: “In ecology, sustainability describes how biological systems remain diverse and productive over time, a necessary precondition for the well-being of humans and other organisms. Long-lived and healthy wetlands and forests are examples of sustainable biological systems.”

I’m sorry, that kind of specificity does not make it more operational.   They haven’t read Solow.  In fact, the whole entry seems to read like it is intended to maximize the number of times it can link to other Wikipedia entries!

“Moving towards sustainability is also a social challenge that entails, among other factors, international and national law, urban planning and transport, local and individual lifestyles and ethical consumerism. Ways of living more sustainably can take many forms from controlling living conditions (e.g., ecovillages, eco-municipalities and sustainable cities), to reappraising work practices (e.g., using permaculture, green building, sustainable agriculture), or developing new technologies that reduce the consumption of resources.”

Actually, the only phrase in the whole entry that really struck me was “more sustainably.”  Now, I REALLY do not know that THAT means.  Our current trajectory is either sustainable, or it’s not!  If future generations can live forever, how can they live longer than that?  And if not, well, …