Australia has a high population growth rate compared with other high-income nations, mainly because of its high level of immigration. Although birth rates are below replacement level, there is also a natural increase in population levels. This is due to the lag effect of increases in population a generation ago, which resulted in increased numbers of women of child-bearing age. There is very little agreement among scientists as to how many people Australia can support, and even less about what environmental impact high levels of population would have. Some biologists, geographers and environmentalists argue that Australia already has more people that the environment can cope with, and that a sustainable population level would be more like ten million people.
Land degradation has sometimes been attributed to population levels. But the NPC’s population issues committee argues that Australian soils are in fact feeding more than fifty-six million people (both within and outside Australia), and that they provide wool and cotton for even more people. Moreover, it argues that the damage done to the soils was done by very small populations: the colonial settlers who cleared the land and the farmers (now less than 5 per cent of the total population) who still clear the land and sometimes cause further soil erosion. Similarly, mining also provides the needs of a wider population. The committee argues that the “environmental impact of any industry which exports a very large proportion of its output is therefore weakly related to domestic population needs and requirements” (pp. 41-2).
It has also been argued by Lyuba Zarsky, an economic consultant, that even coastal tourist development is a result of economic growth in the Asia&endash;Pacific region rather than pressures from population in Australia. “While immigration can exacerbate environmental problems, strong curbs on immigration by themselves will do little to restore Australian farmland, improve forestry practices, or conserve coastline” (1991, p. 125).
Population biologists sometimes talk about the ‘human carrying capacity’ of an area. This refers to the ‘maximum rate of resource consumption and waste discharge that can be sustained indefinitely in a defined region without progressively impairing ecological productivity and integrity’ (French 1991, p. 123). Another term used is ‘cultural carrying capacity’, which recognises that people will not find it desirable to live at the limits of human carrying capacity because the quality of life would be unacceptable. The world could, as indicated above, support many more people living a subsistence lifestyle&emdash;but is that what we want?
The impact that a population has on an area obviously depends on their practices and culture, particularly on how many resources they consume and the volume of wastes they discard. J. H. Cushman and Andrew Beattie, population biologists, point out that the Australian continent ‘could support more Swedes (and far more Ethiopians) than Americans’ (1992) because of the differences in the amounts people from these nations consume (assuming they did not start consuming like Australians when they got here, since Australians consume almost as much per person as North Americans).
Environmental degradation is a product of numbers of people, consumption per person and the environmental impact of each unit of consumption. Increasing numbers of people in Australia will affect Australia’s resource use unless the extra numbers can be compensated for by lower consumption per person or increased resource&endash;use efficiency. In a study for the NPC, G. McGlynn estimated that, in order just to keep resource use constant while population and incomes were increasing at current rates, a 3.11 per cent increase in efficiency of resource use per year would be required. However, another study cited by the NPC showed that increases in efficiency have not exceeded 2.1 per cent since 1965. (Population Issues Committee 1992, p. 44)
Source: Sharon Beder, The Nature of Sustainable Development, 2nd ed. Scribe, Newham, 1996, pp. .