Human civilisation today faces two unprecedented challenges: the threat of climate change and the peaking of global oil supply. Energy supply has been one of the strongest factors in determining human history, and there are strong signs that we are now in the early stages of an energy transition that will shake our economy to its core. At the same time, the accelerating evidence of climate change has made this environmental crisis a top international priority.

Rarely are these two issues considered in combination, but each affects the way we can respond to the other. The possibilities for our future range from "techno-explosion" to civilisation collapse; but another possibility is energy descent, where available energy and organisational complexity progressively decline. Many sustainability strategists believe that energy descent may be inevitable.

There is a desperate need to recast energy descent as a positive process that can free people from the dysfunctions of growth economics. Future Scenarios uses a planning model incorporating the spectrums of climate change and peak oil to generate four "energy descent" scenarios – "brown tech", "green tech", "lifeboats" and "Earth steward" – representing various future pathways. It uses the principles of permaculture – a design system founded on reduced resource availability – to show how we can deal with energy descent in the most graceful way possible.

The Author: David Holmgren is a futurist and the co-originator of the permaculture concept with Bill Mollison. He lives with his partner and their son at Melliodora, a one-hectare permaculture demonstration site at Hepburn Springs, Central Victoria, Australia. David's website can be found at www.holmgren.com.au.