Final (read: terminal) exam
- You have $100 in a bank account that pays 1% interest per year. In year 0, you withdraw $1. In year 1, you withdraw $1.02, and increase the withdrawals by 2% (compounding) every year thereafter. In what year do you run out of money? How much are you withdrawing in the year before your account is cleaned out? How does that change if the account has 10x more capital, but pays 10x less interest? 1/10x?
The earth exceeded capacity in about 1983 according to the Ecological Footprint method of accounting (could have been late 70’s, too – the data is a bit grainy). Each biome would have a different ‘interest rate’, of natural interest/natural capital. For fisheries, that could be as high as 10%. For soils, that may be as low as 0.1%, forests may be about 1%. Each biome would have a different rate of return, and a different rate of increase in consumption over time, but the moment that the withdrawals exceed interest, the natural capital begins to decline. 21 years from first exceedance to collapse for the 10% interest, 159 years for the 0.1%, 71 years for 1%.
On a planetary basis, the rate of increase of consumption measured by Ecological Footprint is approximately 2% per year. The expectation would be that the biomes with the highest natural rate of return would have the fastest rate of decline. Thus it causes us no surprise to hear from the UN FAO that there is no expectation of an open-ocean fishery by 2017. It is of some surprise to note that soil loss will lead to a failure in conventional agriculture by about 2020, until one thinks that soil productivity is defined by the carbon content in the top few inches of soil – until the last of the topsoil washes away, the productivity is unchanged, and we cleared the forests for farming a long time ago.
Using this bank account model of collapse, we would have to assume that we have no foresight at all, and that we are prepared to walk with the lemmings over the cliff. Continuous growth in Ecological Footprint (the rate we’re increasing resource consumption and polluting the ecosystems) will lead to an abrupt end. No amount of technology can change this – in fact, technology that would increase energy or resource use would only accelerate the crash.
This isn’t the only alternative, although it is the only option available on a ‘pure growth’ model.