“Everything that we need for our survival and well-being depends either directly or indirectly on our natural environment. Sustainability creates and maintains the conditions under which humans and nature can exist in productive harmony, [conditions] that permit fulfilling the social, economic and other requirements of present and future generations.” – EPA, 2013 

Sustainability is not just about renewable energy and energy efficiency. Realizing true sustainability requires an understanding of the connections between the environment, society and the economy. We must strive to achieve a sustainability state of mind that permeates all aspects of our day-to-day lives in local, national, and international domains.

Check out this video to learn more about the definition of Sustainability.

A popular method of considering the sustainability state of mind is the triple bottom line approach. The three bottom lines, or pillars, are:

1) Environmental Sustainability

Our most basic requirements: unpolluted air, clean water and fresh food, all come from our environment, as does the energy and raw materials we need for construction and transportation. Environmental sustainability is essential if we wish to have and continue to have the resources to meet our needs. In the broadest sense of the definition, environmental sustainability involves the entire global ecosystem (oceans, freshwater systems, land and atmosphere). However, environmental sustainability principles can equally be applied to ecosystems of any size, even down to the scale of a small home garden.

2) Social Sustainability

A socially sustainable society is one in which all members have equal rights, all share equitably in societal benefits, and all participate equally in the decision-making process. Additionally, a society is unsustainable if it consumes resources faster than they can be renewed naturally, discharges more waste than natural systems can assimilate without degrading, or depends upon distant sources for its most basic requirements. As with environmental sustainability, social sustainability principles can be applied to societies of any size. For example, one of sustainability’s grand challenges is to simultaneously reduce consumption in the developed world while raising the standard of living of the developing world – we need to be responsible global citizens by making informed choices every day within our homes and communities.

3) Economic Sustainability

Economic sustainability is about much more than the sustained growth of resources and profit margins. Economic sustainability takes into account the social and ecological consequences of economic activity. We need to carefully consider the full life-cycle of our goods, from extraction of raw materials, through processing, manufacture, distribution, use, maintenance, repair, and eventual recycling or disposal (the cradle-to-grave paradigm).


A common method of visualizing the pillars of sustainability is a Venn diagram, with each circle representing one of the three primary pillars. However, a more-accurate depiction of sustainability is achieved by using concentric circles to symbolize the pillars, with the most important aspect, the Environment, represented by the outer circle.

The Environment is of primary importance because a healthy ecosystem is required to nourish a robust society. Consequently, Society and Social Responsibility are of secondary importance. Economic Sustainability is third because a prosperous Economy cannot exist without a healthy and just society.

Two different visualizations of sustainability

In reality there are many pillars required to support true global sustainability. Some of these include: the Institutional Capacity for systemic change; the Organizational Capacity for enacting change whilst preserving cultural values; and our own Personal Values – do we possess the moral intelligence to recognize when things are unsustainable and also have the resolve to change them?

We try very hard to define what sustainability is, but often we don’t go far enough. Many aspects of sustainability remain vague. Moral intelligence therefore dictates that we ask difficult ethical questions, such as: What do we mean by “healthy environment”? What does a “robust society” look like? How do we differentiate needs from desires? Is indefinite economic growth plausible? Is sustainability just for the benefit of human life? Is society doing enough? Am I doing enough?

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Office of Sustainability
312-314 Corbett Hall
Orono, Maine 04469-5774
Tel: 207.581.1571