sus·tain·a·bil·i·ty   /səˌstānəˈbilədē/noun>avoidance of the depletion of natural resources in order to maintain an ecological balance.……..   In other words, any resource that is used must be renewable (and renewed) in order to be considered sustainable. If you look to UCLA (who has a great reputation for being a thought and action leader in Sustainability and the environment,) they say:  Sustainability is the balance between the environment, equity, and economy   The UN World Commission on Environment and Development: “sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own…