RICHARD HEINBERG is widely regarded as one of the world's most effective communicators of the urgent need to transition away from fossil fuels. He is the author of nine books, including The Party's Over: Oil, War and the Fate of Industrial Societies (2003), Powerdown: Options and Actions for a Post-Carbon World (2004), and Blackout: Coal, Climate and the Last Energy Crisis (2009). He has authored scores of essays and articles, is featured in many documentaries, and has appeared on numerous television and radio programs. Heinberg is Senior Fellow-in-Residence at Post Carbon Institute.
The essence of the term sustainable is “that which can be maintained over time.” By implication, this means that any society that is unsustainable cannot be maintained for long and will cease to function at some point.
Unfortunately, in recent years the word sustainable has become widely used to refer merely to practices that are reputed to be more environmentally sound than others. Often the word is used so carelessly as to lead some environmentalists to advise abandoning its use. Nevertheless, the concept is indispensable and should be the cornerstone for all long-range planning.
It is probably safe to assume that no human living arrangement can be maintained forever. Astronomers assure us that in several billion years the Sun will have heated to the point that Earth's oceans will boil away. Thus sustainability is a relative term. It seems reasonable to use as a frame of reference for the durations of prior civilizations, ranging from hundreds to thousands of years. A sustainable society, then, would be able to maintain itself for many centuries at least.