Sustainability or sustainable development has been described in terms of three dimensions or pillars, i.e. the environment, the economy and society. The three-dimension framework was initially proposed by the economist René Passet in 1979. It has also been described as “environmental, economic and social” or “ecology, economy and equity.” Some authors expanded three-dimensions by including a fourth pillar of culture, institutions or governance.

The principle of the three pillars of sustainability says that for the complete sustainability problem to be solved all three pillars of sustainability environmental sustainability, economic sustainability and social sustainability must be sustainable.

Most common known definition of sustainability is that from the Brundtland Report of 1987, which said: Sustainable development is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs. It contains within it two key concepts:

The drawback to the Brundtland definition is it’s more inspirational than practical. It’s not precise and measurable, so no one can agree on what it means. This caused the definition to be plagued by controversy from the day it was published. The definition has also fallen into the trap of scope creep by including solving the global poverty problem.

Meanwhile, “development” means economic growth to most nations, especially the developing ones. But that just makes the sustainability problem worse, since the economic system is already unsustainable. In theory, as Hermann Daly and others have suggested, “development” should mean both qualitative and quantitative growth. Qualitative growth (an increase in quality of life) can be very sustainable. But quantitative growth (economic growth) cannot be sustainable once it passes its limit, which it already has.

So, the more sustainable definition of sustainability is: Sustainability is the ability to continue a defined behaviour indefinitely.

The most important of the three pillars is environmental sustainability. If this is not solved, then no matter how hard we try the other pillars cannot be made strong because they are dependent on the greater system they live within, the environment.

A diagram indicating the relationship between the “three pillars of sustainability”, in which both economy and society are constrained by environmental limits