Population growth coupled with consumption lies at the center of any discussion of creating a sustainable world. It is true that Malthus predicted that the geometric growth of population would be stabilized by starvation war and disease back in 1798, and it has not happened yet. But before we pat ourselves on the back and say it will not happen we should consider the cost of postponement. Perhaps the results we are seeing today are in fact far worse than Malthus imagined. In order to increase food and energy production we are extracting fossil fuels at a rate more than a million times faster than they were formed, and depleting the other 10 million or so species that share the earth at an unprecedented rate. In other words we have survived, by using up resources that took hundreds of millions of years to form or evolve in just a few centuries.
The population has more than doubled since 1950 when it reached 2.5 billion. While birth rates are falling in developed countries, the actual growth of population expected in the next 50 years, 2.8 billion, is only slightly fewer than the 3.5 billion in the preceding 50 years. What will life be like with 50% more people on the planet than are here today? Consider that the growth of human population is now, and in the future will be almost entirely determined in the worlds less developed countries (LDCs). Ninety-nine percent of global increase now occurs in the developing regions of Africa, Asia and Latin America with several countries on a growth curve that will lead to doubling (Nigeria) or even tripling (Ethiopia) in population by 2050. These are precisely the areas that can least afford the increase in population. Not only are they already overcrowded, but they lack the resources, such as water, arable land, infrastructure, and money to increase food production. While it is true that the developed nations consume a disproportionate share of the world's energy and raw materials, the populations of less developed countries do significant damage to the biological resources in their efforts to survive.A recent report on the condition of Guatamala's National Parks exemplifies the problem. The population of the area has grown from 20,000 in 1960 to nearly 500,000 today, contributing to countless slash-and-burn fires to clear land for farming and to increased levels of poaching and illegal logging.
Simultaneously we are increasing our per capita use of raw materials and energy. It is abundantly clear with the U. S. using 25 % of the worlds energy, 30% of the worlds paper, and a like portion of other resources with only 5% of the population, that it will not be possible for the LDCs to rise to our level of consumption. In effect, just as the consumption of resources on a global scale is impoverishing our planet for future generations, the wealth of the developed nations demands that the rest of the world remain in poverty.
From a different perspective, David Hacket Fisher in The Great Wave, correlates population growth to the great waves of inflation that were followed by severe hardship during the plagues and famines of the middle ages, the end of the Renaissance, and the late18th. century (the American Revolution, the French Revolution, and numerous rebellions). His analysis makes it clear that population pressure has been the the trigger for for much of the social and political disruption since the 12th. century, though the mechanism has been prices fluctuations, not outright starvation as Malthus predicted.
Those who propose that population growth is not a major problem, point to the technological fix of new varieties of higher yielding crops, of reducing the consumer excess in the west and sharing the wealth with the LDCs. They talk of the amount of land not yet used for growing crops, and they talk of reviving nuclear power industry and finding new energy sources. First, they are not seeing that every technological advance in one area merely shifts the burden of over consumption to a different aspect of the environment. Higher yielding crops require more inputs of energy (fertilizer), and water. To increase energy production requires some combination of water, land and capital. and will add some form of waste products to the system. It is a fruitless cycle, and in the long run, no matter how well the new technologies are managed, uncontrolled population growth will overwhelm all technological solutions.
Population control is central to any strategy to create a sustainable world. There are many opinions as to what a sustainable population is, but several writers have come up with a figure between 1.5 and 2 billion in order to allow everyone the possibility of a life above the subsistence level.* As the Ehrichs say in The Stork and The Plow, "To our minds, society that is on the margin, whose resources are stretched almost to the limit and that has little scope for supporting more people without sacrificing the well-being of much of the present population or of future generations, has little choice but to exercise stringent population control. Failure to do so amounts to a policy of blind and insensitive promotion of misery." We are all living on the margin.
*Optimum human Population Size; G, Daily, Ann Ehrlich, P. Ehrlich; Population and the Environment, 1994, 15(6) 469-475