The SiD Definition of Sustainability

Sustainability is the state of a complex, dynamic system. In this state, a system can continue to flourish resiliently, in harmony, without requiring inputs from outside its system boundaries.

Applied to our civilization, this state is consistent with societies powered by renewable energy and closed-loop material systems, inhabiting thriving ecosystems, on a biodiverse planet, with healthy and happy individuals living in just, tolerant, and diverse cultures, supported by open and transparent economies.

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The first two sentences define what sustainability is in an actionable and testable way. The second part exemplifies what the definition means when applied to our civilization.

The next activities and steps will unravel the first two sentences, discussing the definitions of ‘systems’, ‘state’, what we mean by ‘complex’ and ‘dynamic’, and how do we tell a sustainable system from an unsustainable one.

If you understand why the definition is formulated this way, you’ll grasp the most important lesson in this course.