What is sustainability? Ask 10 people and you well may get 10 different answers. Most people will mention at least one of the following components: economic, social, or environmental. One of the most common comes from a 1987 United Nations commission. It states “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” However, sustainability also has varying levels. Referred to as weak, strong, and super strong, these three distinctions have specific distinctions separating them from one another.

In a 2004 article titled “The diverse and contested meanings of sustainable development” by Colin Williams and Andrew Millington in The Geographic Journal, the authors define weak sustainability by the following factors:

• a human-centered worldview is adopted;
• there is an emphasis on a growth-oriented approach to economic development;
• there is a relative lack of consideration given to the need for radical change in people’s demands on the earth and
• there is a perpetuation of the view that nature is merely a collection of natural resources that can be subdued by the human race.

Weak sustainability is the prevailing approach to sustainability in the western, industrialized world. It allows for the continuation of current trends by placing growth ahead of development. Capitalist systems have traditionally equated sustainable development with sustained growth. In their article, Williams and Millington point out that a central tenet of weak sustainability requires “Technological progress [to] enable people to manipulate the Earth to meet their enormous demands on it. [In other words,] Any problems that arise will thus be solved through technological development.”

As a counter to weak sustainability, strong sustainability advocates argue, we need “a more small-scale decentralized way of life based upon greater self-reliance, so as to create a social and economic system less destructive towards nature.” Strong sustainability does not make allowances for the substitution of human and human-made capital for natural capital. The products created by mankind cannot replace the natural capital found in ecosystems.

Robert Goodland, formerly of the World Bank, defines weak environmental sustainability as “maintaining total capital intact without regard to the partitioning of that capital among the four kinds,” namely natural, social, human, and human made capital. He states that strong environmental sustainability “requires maintaining separate kinds of capital. . . . This assumes that natural and human-made capital are not perfect substitutes.” Lastly, he refers to “Absurdly strong [or 'superstrong'] environmental sustainability,” which would “never deplete anything.” In essence, there would be no use of non-renewable resources (including energy and minerals), and renewable products would only be harvested “in the form of overmature portion[s] of the stock.”

The current course of humanity falls short of even weak sustainability, although the tenets (as posited by Williams and Millington) fit our current approach. While strong and super strong sustainability may be out of reach, and threaten our economic position, mankind must strive toward some of these goals, specifically self-reliance and sustainable harvesting of renewable goods.

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