Sustainability is the practice of maintaining processes of productivity indefinitely—natural or human made—by replacing resources used with resources of equal or greater value without degrading or endangering natural biotic systems. Sustainable development binds together concern for the natural systems with the social, political, and economic challenges faced by humanity.
The three pillars of sustainable development are the economy, energy and the environment. Interaction between these three pillars sustains a growing global economy which provides employment for millions of people and a decent standard of living in a healthy environment and the energy means that help enhance the quality of our life and mobility. The global economy has to be in a continuous state of healthy growth if it is to be able to feed 7.5 billion of people.