3.7 Limits to Growth

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3.7.1: Explain difficulties in applying the concept of carrying capacity to local human populations.

  • Wide range of resource used
  • Lifestyle effect resource requirement
  • Technological development changes resources required and available for consumption
  • Resources can be imported or recycled

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. Furthermore, when one resource becomes limiting, humans show great ingenuity in substituting one resource for another. Resource requirements vary according to lifestyles, which differ from time to time and from population to population. Technological developments give rise to continual changes in the resources required and available for consumption.
Human populations also regularly import resources from outside their immediate environment, which enables them to grow beyond the boundaries set by their local resources and increases their carrying capacity. While importing resources in this way increases the carrying capacity for the local population, it has no influence on global carrying capacity. All these variables make it practically impossible to make reliable estimates of carrying capacities for human populations.


3.7.2: Explain how absolute reductions in energy and material use, reuse and recycling can affect human carrying capacity.

Human carrying capacity is determine the rate of energy and material consumption, the level of pollution and the extent of human interference in global life-support systems. While reuse and recycling reduce these impacts, they can also increase human carrying capacity

  • Recycle: when a household or industrial waste is reused and made into another product, like plastic, metals and paper.
  • Re-use: when a product is used more than once by returning it to the manufacturer or processor each time. This is very energy efficient and more efficient than recycling.
  • Reduce: this is when energy use is decrease for example turning off the lights when not needed or using the amount of water needed in a kettle.
  • Substitution: when using one resource over the other, the use of renewable source over a non-renewable source is a major benefit to the environment.