To be read in conjunction with the One Planet Equation page
The One Planet Equation is not to be interpreted as an exact mathematical formula but a mind model that relates the availability of resources and their consumption. It is only valid if a resource is constrained.
When a resource is constrained then both sides of the equal sign must remain equal to one, and as total resource use is equal to the number of people consuming them and the amount of the constrained resource in each unit of consumption, P*C. At the choke point of resource availability we have 1 total population and 1 total resource use so P*C=1 but as they grow, they grow just like money in a bank, at a compound, or exponential rate.
To keep P*C=1 as they grow then we have to introduce a factor 1/P*C, the resource intensity, to keep the total equal to one. It is essential to realise that this is only a mind model and in the real world different people are consuming at different rates and P*C is an aggragated total.
The implication is clear though that if we want populations to have an increasing access to goods and services, the amount of resource per unit of consumption, resource intensity must be continually reduced and leads to the first law of sustainability – that in a resource constrained environment, goods and services can only grow at the rate at which they can be dematerialised. e.g. CD’s to music downloads, physical mobility to tele and video-conferencing.
This leads to the first thought when attemping to reduce resource intensity – can a product be transformed into a service?
Note – the above arument masks the inequity in per capita consumption between people and societies.
To be continued