What is Sustainability?
Contrary to popular belief, sustainability is not solely about maintaining environmental quality. Rather, it is a systems way of thinking that emphasizes the need to focus on interactions between humans and their environments. "Environments" does not mean only the physical natural world around them, but also includes societal position, economic ability, living conditions, etc. In practice, sustainability is encompassed by three E's (or three P's), where all three areas must be achieved to be truly sustainable.
Environment (Planet) focuses on ensuring a healthy natural world that is able to maintain its natural processes without much intervention by humans.
Equity (People) refers to a society in which individuals are given relatively equal opportunities such that they can meet their needs and live a healthy lifestyle, both physically and mentally.
Economy (Prosperity) is centered around providing all individuals with economic opportunity so that they have a good quality of life and can maintain that quality over a long period.
To pursue sustainability is to create and maintain the conditions under which humans and nature can exist in productive harmony to support present and future generations. - US Environmental Protection Agency
Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. - UN World Commission on Environment and Development
An inclusive way, encompassing human and ecological health, social justice, secure livelihoods and a better world for all generations. - Association for the Advacement of Sustainability in Higher Education
The need to ensure a better quality of life for all, now and into the future, in a just and equitable manner, whilst living within the limits of supporting ecosystems. - Julian Agyeman, Robert Bullard, and Bob Evans