Human carrying capacity and
the ecological footprint
In this topic we will § Review the concept of carrying capacity § Describe the concept of an ecological footprint § Calculate ecological footprints for data
And we will discuss several processes § Factors affecting human carrying capacity and limits to growth § The difficulty in applying the concept of human carrying capacity § Affect of reuse, recycling and remanufacture on carrying capacity § Differences between ecological footprints for different regions § The effects of development policies on population growth § The effects of technological development on population growth
IB EVS Ecosystems and Societies Resources 4: Carrying capacity and the ecological footprint
- 1 - DH La Chat 2004 modified JR Oakham 2005
Review of carrying capacity Draw a sigmoid growth curve for an animal population. Label the phases of growth and indicate the carrying capacity.
Carrying capacity is defined as the maximum population of a given species that can be supported indefinitely in a particular habitat without permanently damaging that habitat.
Can the concept of carrying capacity be applied to local human populations? (3.7.1) In 1798, when the human population was about one billion, Thomas Malthus, and economist, wrote, 'The power of the population is infinitely greater than the power of the earth to produce subsistence for man'. In 1976, when the population was 3.5 billion, an environmentalist, Paul Ehrlich warned of 'famines of unbelievable proportions' and that feeding six billion (passed in 1999) would be 'totally impossible in practice'. So far these predictions of disaster have been wrong and human carrying capacity may continue to increase. It may not be possible to extrapolate (predict) any maximum human population.
Read the following paragraph and highlight the various ways in which local human populations can exceed the natural carrying capacity of the area in which they live.
By examining carefully the requirements of a given species and the resources available, it might be possible to estimate the carrying capacity of that environment for the species. This is problematic in the case of human populations for a number of reasons. The range of resources used by humans is usually much greater than for any other species e.g. fossil fuels and minerals. Furthermore, when one resource becomes limiting, humans show great ingenuity in substituting one resource for another e.g. replenishables for nonrenewables or substituting manufactured capital for some form of natural capital that might run out e.g. textiles. Resource requirements vary according to lifestyles, which differ from time to time e.g. pre- and postindustrial and from population to population e.g. housing in a tropical region compared to Europe. Technological developments give rise to continual changes in the resources required...