A Science-Based Definition of Sustainability

The Framework For Strategic Sustainable Development revolves around a robust, science-based definition of sustainability. “Robust” means that the principles contained in this definition are both necessary and enough to achieve sustainability. They are also applicable to any activity at any scale and they don’t overlap (each principle covers its own domain).


Context:  If Earth is a system, we’d better understand the conditions it needs to keep running the way we like it

Left to its own devices, the earth is a sustainable system. As we continue to learn, however, over the past two centuries the accumulated impacts of one group of actors in that system (humans) are now threatening the stability of the whole thing. That affects our continued well-being. In fact, it is exactly like sawing off the tree branch on which we sit.

An international network of scientists have unanimously and publically concluded that human society is altering life-supporting natural structures and functions in three fundamental ways. Consequently, they were able to define three basic “system conditions” that must be met if we want to maintain the essential environmental services that sustain human society.

Further, because human action is the primary cause of the rapid change we see in the natural environment today, they included a fourth system condition that focuses on the social and economic considerations that drive those actions–recognizing that human beings will always prioritize the meeting of their basic needs (just like every other creature on the planet).

Together, these form the “trunk and branches” of our approach to strategic sustainable innovation and development.

While written to be clear scientifically, the specific wording of the four system conditions can be confusing to non-scientists. However, the system conditions can be reworded as basic sustainability principles that provide explicit guidance for any individual or any organization interested in moving towards sustainability. In most instances, we refer to the basic sustainability principles.

In a sustainable society, nature is not subject to systematically increasing …

  1. … concentrations of substances from the earth’s crust (such as fossil CO2 and heavy metals),
  2. … concentrations of substances produced by society (such as antibiotics and endocrine disruptors),
  3. … degradation by physical means (such as deforestation and draining of groundwater tables),

…and in that society …

  1. … there are no structural obstacles to people’s health, influence, competence, impartiality and meaning.

What Does This Mean for Us?

At first reading, the system conditions and sustainability principles might seem to imply that we must stop extracting all materials from the earth and stop producing all human-made substances and that, further, we must never disturb a natural landscape. But that’s not what they mean. The problem is not that we mine and use heavy metals, or use chemicals and compounds produced by society, or disrupt natural processes. It is, rather, that our industrial and economic systems have developed so that environmentally damaging practices like these will continue to grow indefinitely, having greater and greater impacts over time. As long as our impacts were small relative to the capacity of the planet to handle them, the big picture wasn’t so scary. But because we are systematically increasing these impacts, they are now large and getting larger. As a result, we are at the point where there really aren’t “plenty of fish in the sea”. This is the trouble. These systematic increases cannot be sustained on a finite planet.

With respect to the fourth sustainability principle, as long as people’s basic needs go unmet, we will cut the last tree, dam the last river and pull the last fish from the sea in our efforts to survive. So we can’t have environmental sustainability without social sustainability. Besides, it’s no use building a world where our own well-being isn’t included in our definition of success!

What Can We Do About It?

To learn more about The Natural Step’s approach to dealing with the challenges of implementing this necessary shift in how we design, build and do things, have a look at the following pages.