1. Defining “Sustainability”
Danny Harvey
Department of Geography
University of Toronto

2. Four Principles of Sustainability (HOK Guidebook to Sustainable Design)
Substances from the Earth’s crust must not systematically increase in the ecosphere
Substances produced by society (man-made materials) must not systematically increase in the ecosphere
The productivity and diversity of nature must not be systematically diminished
There must be fair and efficient use of resources to meet human needs (basic needs for all take precedence over providing luxuries for the few)

3. I would add a 5th and 6th principle of sustainability:
Human energy needs must be met entirely from renewable energy sources, without degrading the longterm capacity of nature to supply energy renewably
The local rate of consumption of freshwater must not exceed the rate at which freshwater is supplied through the hydrological cycle in excess of ecological needs

4. There are both resource and environmental constraints on sustainability
Resource constraints – resources eventually become prohibitively expensive
Environmental constraints – environmental consequences undermine basic life-support systems or create societal instabilities

8. Stabilization of Climate at (hopefully) non-catastrophic levels (CO2 peaking at 450 ppmv), and Sustainable Development (requiring, among other things, a Sustainable Energy System (one based on Renewable energy)) are Flip Sides of the Same Coin (there is no conflict between the too): Both require completely phasing out the use of fossil fuels (the former before 2100 AD).

9. The longterm per capita energy use consistent with sustainability depends on the human population. For populations peaking at 8-9 billion, per capita energy use in OECD countries needs to fall by at least a factor of 4 (and renewable sources of energy rapidly ramped up)

12. Energy and the New Reality:   Facing up to Climatic Change   Island Press, Washington   Late 2008 Publication

13. A Sourcebook on Low-Energy Buildings and District Energy Systems: Fundamentals, Techniques, and Examples    James & James / Earthscan (London)   Published July 2006