I merged my two leading models of the relationship between resource consumption and population into one combined population model, which shows better than ever the constraints on future growth. The new model uses a generic definition of “resources,” measured in units of mass, and incorporates access to the resources and response to perceived depletion of resources into the mathematical description of consumption. Renewable resources (“capacity”) are counted as non-renewable resources which don’t begin to be depleted unless consumption exceeds the amount that is replaced.
We have several options:
(1) We can continue business-as-usual, which will result in a catastrophic depletion of resources associated with a population crash. The timing is the same as before, beginning with a population peak about 30 years from now.
(2) If we want to continue the growth in consumption and population we’re currently enjoying, we must access new resources by about 10% per year if we start in 2010. This growth can be sustained for a maximum of another 200 years, when we will be unable to move resources fast enough and be faced with the same prospect we have now – population collapse.
(3) We could stop growth in overall consumption. Beginning in 2010, this would buy us another 30 years or so.
(4) If we could somehow decrease our consumption without adversely impacting population (for instance, by distributing resources to poor people so the reduction doesn’t kill them), then we could stretch our resources longer. If the minimum per capita consumption is what the average was in 0 A.D., then we could stretch our resources no more than about another 1,400 years if we start in 2010 (less if we start later).
(5) We can attempt to increase the amount of renewable resources to a level just above the consumption that could sustain a preferred population size and keep our consumption constant. We would use non-renewable resources only as necessary to adjust to changes in renewable resources (and help make those changes). Starting in 2010, I estimate that to avoid the impending population crash, we would need to increase renewable resources by at least 16% per year while keeping consumption constant. While theoretically we could do this indefinitely, we would only have two years' worth of non-renewable resources to handle contingencies.
(6) We could use a mixed strategy of growth and sustainability. This would involve simultaneously increasing our access to both renewable and non-renewable resources while restricting growth in consumption. I estimate that in the best case (keeping consumption constant) we could extend resources more than 1.6 million years.