Will we be able to feed the world’s burgeoning population? The heated debate about whether we will be able to grow enough food to feed the world’s ever-growing population has raged for centuries. There is a large literature on the debate over world agricultural futures, and projections differ broadly based on assumptions of yield growth. Expert opinion is divided into two camps. The survivalists believe the Earth has limits that we are fast approaching. The Prometheans, on the other hand, believe we can produce more than enough food due to technological innovation and continued investment of human capital (Dryzek, 1998).
Environmental problems have famously been cast in terms of the capacity of Earth to support life, human life in particular. In 1798, Thomas Malthus wrote an ‘Essay on the Principle of Population’, stating that the population was held in check by ‘misery, vice and moral restraint’. He maintained that ‘population when unchecked increased in a geometrical ratio, and subsistence for man in an arithmetical ratio’ (Malthus, 1798).
This argument received fresh stimulus in the 1960’s, when the earth was viewed from space for the first time. This image of ‘spaceship Earth’ stressed the finiteness of the planet and our resources (Jacobs, 1991). This image coincided with Ehlrich’s warning of the ‘population bomb’ (1968) that was going to exhaust natural capital stocks. Hardin’s influential essay on ‘The Tragedy of the Commons’ was published in the same year. Both stressed that the growing population and environmental degradation due to rapid economic growth meant that we were going to exceed the global ecosystem’s boundaries. In 1972, ‘Limits to Growth’ which contained a computer generated projections of the global future was published, that projected that we were very close to overshooting these limits. Simply put, this camp argues that exponential growth cannot go on forever in a finite system. This argument rests on the concept of carrying capacity.
In ecology, ‘carrying capacity’ is defined as ‘the maximum number of individuals of a species that an ecosystem can sustain’ (Beeby, 1993). Carrying capacity can also be defined as ‘the maximum population of a given species that can be supported indefinitely in a defined habitat without permanently impairing the productivity of that habitat’ (Rees, 1991). This concept suggests that no living populating can grow forever. The competition between species for space, food and other resources impose a natural limit on the number of individuals of a population that any ecosystem can support. When population biologists turn to human affairs they see identical possibilities (Catton, 1980). According to Hardin (1993; 207), the ecologist’s Eleventh Commandment is ‘though shalt not transgress the carrying capacity’.
It has been argued that the concept of carrying capacity make sense at a global level but not at a regional level, Even if cities vastly exceeded carrying capacity of their local ecosystems they can exploit distant resources and sinks for their pollutants in order to support large and sometimes growing populations (Rees, 1992). According to Rees (1996) ‘ecological locations of human settlements no linger coincide with their geographic location. Since for every material flow there must be a corresponding ecosystem source or sink, the total area of land/water required to sustain these flows of a continuous basis is the true ‘ecological footprint’ of the referent population on earth’. But it has been noted that the supposed increase in carrying capacity as a result of trade is illusory. ‘Trade may release a local population from carrying capacity constraints in its own home territory, but this merely displaces some fraction of that population’s environmental load to distant export regions. The net effect is to create unsustainable dependences on enhanced material flows while reducing long term carrying capacity’ (Rees, 1996). In fact, this may even result in reduced global carrying capacity if access to cheaper food lowers the incentive for people to conserve their own agricultural land, and this leads to the accelerated depletion of natural capital in distinct export regions. Current prices are also not an adequate measure of the value of future shortages of resources and of current and future harm, as we do not know the ecological value of exports and imports. Unfortunately, prevailing economic models of growth and sustainability ‘lack any representation of the materials, energy sources, physical structures and time dependent processes basic to an ecological approach’ (Christensen, 1991). Ecological economists reason that neoclassic economic models cannot properly address this question as they do not take into account ecological structure and function (Costanza, 1994).
As Dryzek (1997) notes, we still do not have a consensus as to how seriously impaired the world ecosystems are, or what the potential for continued development for the growing population is. The good news seems to be that we can feed more than 6.5 billion people. The bad news, however, is that we seriously compromising our life support systems to accomplish this. Feeding a growing world population may be feasible technologically but the economic and environmental costs may prove too great for poor countries. Additionally, a more troublesome question is, is this technological enhancement at acceptable environmental costs? For example, the green revolution during the first 35 years doubled grain production but at a high environmental cost. While the revolution increased per capita food production, increasing the yield per hectare requires abundant quantities of fertilizer and water, and thus this increase was achieved at reasonable cost (Tilman, 1998). Ecologists have warned us that the imprudent of natural resources may irreversibly reduce the carrying capacity of the planet for in the future (Harris, 1994).
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