Carrying Capacity and Singapore

I remember reading with great interest some forum with regards to population size, and carrying capacity with regards to Singapore.

For the technically uninclined, here's the definitions for the key word.
Carrying capacity: The maximum population size that can be supported by the available resources, symbolised as K. (Campbell and Reece, 2005)


The forum page had someone try to calculate the carrying capacity of Singapore using area size (680 sq kilometres or 168,032 acres roughly) and the average area of land required to feed an average American (something like 1.5 acres). So that gives a figure of K=112,021 people that Singapore can support. Given that the Singapore Government is targetting 6 million to sustain long-term economic growth, the post then asserts that the population of Singapore will plunge by more than 90%. This is very alarmist. The problem is far more complex than the writer thinks. Global carryng capacity for humans lies around 10-15 billion (depending on who's calculation you look at). And given the way we import our food, effective land use in this aspect for Singapore is actually far bigger than the actual land area of Singapore itself. However, all these calculations should not be taken too seriously.

Carrying capacity is a snapshot number. It is dependent upon many factors, like technology and efficiency, production and consumption, and the interactions between the biotic and abiotic factors in the environment (Arrow et al., 1995). A single technological innovation in primary production may significantly raise carrying capacity, just as a single comet hitting the Earth will significantly reduce carrying capacity.

The example of the collapse of the Roman population in the ancient times was also cited, but these were self-sustaining, agricultural populations, a period of time which technology very much infantile, way before innovations like the Haber process.

Perhaps we should look at other indicators. How much of global terrestrial primary production is taken by humans. It's actually around 40% (Vitousek et al.), and probably rising due to forest and arable land loss due to poor farming practices, and an exponentially increasing human population and the accompanying increase in consumption. Now that statistic makes more sense, and should make people sit up and take notice.

How do we relate the 10-15 billion carrying capacity and the disproportionate amount of primary production we consume given we're only halfway, or less to the limit? I think here, perhaps it is useful to recall again that the carrying capacity number is a snapshot number, done using curves and models of the current situation (or the situation as of the calculation). One thing that mathematical models cannot predict is preference, and the human desire for excess. People are not content with enough. They want 'more than enough'. Everyone wants to consume at the rate of Bill Gates and Hollywood celebrities. That is one of the main problems. As the human population increases, and the corresponding number of people having such desires, and a good number of them working towards and 'achieving' these targets, the scenarios start to change. Mathematical parameters change, and the carrying capacity is slashed because what society deems as enough is actually ecologically excessive. Couple that with the exponential increase in human population, then it might seem that the two limits are racing towards each other.

At this point in time, it's not the end of the world. A 90% drop in population for Singapore is way off the target for now, while the current estimates of carrying capacity remain relatively high up. However, we should not try to meet carrying capacity. In fact, the further away we are from carrying capacity the better. There must be a significant buffer between the two points. We could go about it by working on both points. Raise the carrying capacity, and reduce the rate of human population increase. People should control and bring down the upper limits of consumption, so more resources are freed up and this can actually increase carrying capacity. Nations with disproportionate increase in populations should also watch their birth rates. If not for ecological reasons, then for humanitarian reasons, as often, these are areas where poverty levels are relatively high.

So how does Singapore fit in all this? 6 million people seems a lot for an island nation like ours, especially during rush hour in the MRT trains, but the effective terrestrial land use area for things like food production and energy resource extend the area far beyond her sovereign boundaries. Singapore is technologically advanced, with a top notch sanitary infrastructure (I know coffee shops leave a lot to be desired but at least the flushing works and it's not a hole in the ground). As such, carry capacity for Singapore in effect could be very high indeed. HOWEVER, that said, our problem, like much of humanity, is that we still require a massive shift in mindset in terms of our consumption and our attitudes towards nature, biodiversity, conservation and their balance against economic growth and well-being.

References:
Campbell, N.A and Reece, J.B. (2005) Biology. 7th Edn. Pearson Education Inc.

Arrow, K., Bolin, B., Costanza, R., Dasgupta, P., Folke, C., Holling, C.S., Bengt-Jansson, B-O., Levin, S., Maler, K.G., Perrings, C., and Pimentel, D. (1995) Economic Growth, Carrying Capacity and the Environment. Science 268: 520-521

Vitousek, P.M., Ehrlich, P.R., Ehrlich, A.H., and Matson, P.A. (1986) Human Appropriation of the Products of Photosynthesis. BioScience 36: 368-380