Sustainability is difficult to define, but essential to understand and try to implement. My first memory of the concept (but not the term) was the photo of Earth taken from the Apollo spacecraft. That image etched the idea of “limits” into my consciousness, and limits or ­system boundaries are key aspects of sustainability. One of the best-known definitions is from the United Nation’s Brundtland Commission: Sustainability is meeting the needs of today without compromising the ability of future generations to meet their needs. This has to do with balancing economics, environment, and people. It is not a new concept. Romans […]