Well there are a lot of things that are encompassed by the word Sustainability. I would start explaining with the "3Rs - Reduce, Reuse, Recycle" which is pertinent to our daily usage of material resources. Then you can explain the concept of "embodied energy", how everything that surrounds us is an embodiment of the energy spent on it. We can also talk about energy sustainability, water sustainability, carbon footprint etc. 

All of human history had the concept of sustainability. All the ancients believed in it. Only in the recent times that we are distancing ourselves from the concept of sustainability when it is needed most than any other time in human history. Although, the word sustainability might be new, the concept itself is not! Whether the Japanese said: "Mottainai" or the Native Americans said: "We do not inherit the Earth from our ancestors, we borrow it from our children", they all are referring to sustainable living.

Hi Srikanth,

Thanks for your answer. It makes lots of sense and introduces the idea that sustainability is not a new idea; quite the contrary, it looks like going back into the classics. When looking at the Oxford Dictionnary there are at least two possible interpretations of sustainable/sustenable. One involves the idea of maintenance without any external investment or drain of resources; this seems to revolve around the idea of a 'close' system. Another might be about the issue of doing something that can be defended as valid or correct; in this sense involving an ethical stance.