There is probably no word more overused in environmental vocabulary than “sustainability.” Universities have sustainability officers. Fisheries biologists and foresters talk of maximum sustainable yields. Corporations tout sustainable development. Not far beneath the surface, all of these folks are really interested in raising the impact, harvest or profit of their operation, with the best possible public image.

Sustainability became vogue in 1987 with the publication of the Brundtland report—Our Common Future, defining sustainable development as:

“Development that meets the needs of the present without compromising the ability of future  generations to meet their own needs.”

From its inception, sustainability was human-centric, focusing attention on our ability to continue to supply Earth’s resources to humans now and in the future, even though many of those resources are finite and their use thus unsustainable by definition. For instance, groundwater is regenerated only at millennial timescales so its use at any level is unsustainable for the next generation of humans. Does that mean we should not use it? No, but we ought to be realistic about what we are doing and call it unsustainable.

Economists often argue that additional resources come to market as the price rises from current resource depletion. This has happened recurrently with petroleum. But does that mean there is more oil in the Earth’s crust? No, our use is unsustainable if we want these hydrocarbons for future generations. Sustainable growth from a finite resource base is an oxymoron. Let’s call it what it is.

Even for resources such as forest products and fisheries that have some ability to regenerate, the human-centric definition of sustainability ignores impacts on other species of the Earth system that are important to humans. When we harvest forest products at a sustainable yield, the trees are normally planted in monoculture and rows, which severely depletes biodiversity—now known to be important to human health and well being. When stable and putatively sustainable crop yields are maintained by the use of pesticides such as neonicotinoids, they are not sustainable if the future populations of pollinators for those crops are decimated. What might appear sustainable today must consider the impacts on species that determine resource yields tomorrow.

Today’s definitions of sustainable are usually based on today’s estimates of baseline conditions in natural ecosystems, already depleted by centuries of human exploitation. Talk of a sustainable yield of ocean fishes, whose populations are now only 10 percent of historical levels, codifies lower resource availability for future generations. Witness the lack of recovery in North Atlantic cod populations even though the commercial harvest in the Gulf of Maine has been prohibited for some years.

Sustainability science ignores the “flip-side” of resource use: waste product generation. As we watch the atmospheric levels of carbon dioxide rise year by year, it is clear that human use of the atmosphere as a dumping ground for the waste products of an industrial society has exceeded the planet’s ability to cleanse them. Even constant carbon dioxide emissions to the atmosphere would not indicate a transition to sustainability, as a certain fraction will always remain airborne to disrupt the climate for future generations.

Nitrogen fertilizer may ensure stable or growing agricultural yields for the future, but also rising nitrous oxide in the atmosphere, threatening climate change and exposure of each of us to damaging solar ultraviolet light. Rising concentrations of nitrate, mercury and xenobiotic compounds in the environment speak strongly for the unsustainable management of human wastes. Sustainability must look beyond resource availability and consider the impact of the effluents of modern society on human health and climate.

Indeed, I can’t think of any resource use that is sustainable under the pressure of rising human population and the desire of all people to live well, capturing their share of the Earth’s resource bounty. Unfortunately, it is the other species that share the planet with us that will suffer the most. When we harvest the ocean’s fisheries at what might appear to be sustainable yields, seabirds that also depend on those populations suffer. We can fool ourselves about the current fishery, but future generations are not likely to enjoy many seabirds.

In my recent reading of Deborah Cramer’s The Narrow Edge, I found lengthy discussion of the plight of an iconic shorebird—the red knot—from coastal development, the harvest of its preferred food (horseshoe crabs), and climate change. Nowhere does she mention that all of these impacts on the red knot are driven by more people, occupying more land, burning more fossil fuels, and consuming more food. The plight of the red knot is ultimately from an unsustainable rate of human population growth on a finite planet—the horseshoe crab is merely the vector that carries our impact to the birds.

For environmental resources, “reduce, reuse, and recycle” are laudable goals, which should be pursued with vigor. But more people inevitably cause the total resource use and environmental impact to increase. So long as the human population on Earth is growing, nothing we are doing is particularly sustainable if we hope to live above the poverty level. We ought to expunge “sustainable” from the environmentalist’s lexicon.

References:

Brundtland, G.H. 1987. Our Common Future. World Commission on Environment and Development. Oxford University Press.

Burger, J.R., C.D. Allen, J.H. Brown et al. 2012. The macroecology of sustainability. PLoS Biology 10: e1001345

Civitello, D.J. et al. 2015. Biodiversity inhibits parasites: Broad evidence for the dilution effect. Proceedings of the National Academy of Sciences US 112: 86677-8671.

Cramer, D. 2015. The Narrow Edge—a tiny bird, an ancient crab and an epic journey. Yale University Press, New Haven.

Cury, P.M., I.L. Boyd et al. 2011. Global seabird response to forage fish depletion—one-third for the birds. Science 334: 1703-1706.

Myers, R.A. and B. Worm. 2003. Rapid worldwide depletion of predatory fish communities. Nature 423: 280-283.

Wackernagel, M., N.B. Schulz et al. 2002. Tracking the ecological overshoot of the human economy. Proceedings of the National Academy of Sciences, US. 99: 9266-9271.