question: is there such thing as a human carrying capacity?

We are all living together here on this big beautiful green and blue rock we like to call Earth.  She provides us with so many wonderful things – most importantly the raw materials and environmental services that keep us alive.  Despite being so lucky as to have these gifts from nature, we as humans seem to continuously want more and more and more.  Now we have what is known as an ecological overshoot.  This means that there is an excess annual demand for the resources the earth can provide.

ecological overshoot

Normally, the overall population of humans should start to decrease because of a lack of resources needed to sustain the 7.5+ billion people.  This phenomenon refers to carrying capacity or the population size at which the population growth rate is zero. Population growth rate is affected by food availability, competition for resources and the impact of predators and disease. When the population size is smaller than the carrying capacity, the population will grow. If the population is greater than that of the carrying capacity, the population will decrease. Eventually, equilibrium will be reached and the population will stabilize. This occurs because birth and death rates are density dependent (as a result of competition for resources).

carrying capacity
source: scanlin350.wikispaces.com

When discussing humans, carrying capacity takes on a slightly different meaning. In terms of humans, it means the number of individuals that would be able to live at a certain standard of living and level of resource consumption. If everyone were to live at the standard of living like in the United States, the carrying capacity would be much lower than if everyone lived with lower standards.

Carrying capacity is difficult to address when dealing with humans because humans can remove or adjust many of the environmental constraints that would normally control a population’s size. This has enabled humans to expand to a population larger than that of what the world can sustain – without dramatic lifestyle changes in the western world and/or dramatic decreases in populations in developing worlds.

To find out about how your ecological impacts of your lifestyle, test your ecological footprint with an  Ecological Footprint Analysis.