As we begin to address global challenges such as climate change, peak oil and over-population it is becoming apparent that we must re-orientate our society towards lower energy availability. This means that in the future, we will need to live in a world where our resources are produced and accounted for much closer to home. We will need to begin to live within the long term carrying capacity of our landscapes.

A prototype Carrying Capacity Dashboard has been developed to estimate the productive capacity of the Australian landscape at various scales: national, state and regional.

The Dashboard allows you to test how many people the resources of a certain area may support as well as determining how various lifestyle choices can influence land-use requirements. You can assess options such as a population’s diet, agricultural techniques, energy usage and recycling practices to gain real-time results. This form of modelling can help determine optimal placement, size and configuration of future human settlement as well as promoting societal behaviour consistent with the limits imposed by the natural environment.

The Carrying Capacity Dashboard is a prototype only and is currently being developed by Murray Lane as part of his PhD at Queensland University of Technology. We value your feedback on the Dashboard, and also your contribution to the Carrying Capacity Blog below.

Global Models - Limits to Growth

Carrying capacity assessment estimates the maximum number of people that an area of land can support. A satisfactory carrying capacity model would thus need to encapsulate sufficient aspects of land-usage that impinge on population maximums. This section looks at various carrying capacity assessment models and considers their scale of analysis as well as the insights that they have provided.

Within carrying capacity literature, minor variations exist in the manner to best arrange the physical and sociological components of a carrying capacity model, but generally, they encapsulate similar fundamentals. For example, Fearnside[5] cites population, a particular area, environmental degradation plus a combination of technology and consumptive habits; House and Williams[6] propose resource production, environmental assimilation, infrastructure delivery and quality of life concerns; Thurow[7] profers production, consumption, egalitarianism and social discipline; while Hardin[8] reduces resources and lifestyle to a concept of cultural carrying capacity. Despite these differences, most authors define the limits to population by either their required inputs or subsequent outputs. Whether these inputs and outputs are culturally, technologically, economically or physically determined, they still form the basic determinants of carrying capacity. So, in essence, resources form the limiting factor on the input or supply side of the equation while environmental impacts form the opposing carrying capacity barrier on the output side. The population is wedged between these barriers but can alter the demands of each by collectively altering its behaviour.

An assessment of current carrying capacity literature suggests that methodologies can be categorised into approaches that focus more or less on the various components of a basic carrying capacity model (Figure 11). These elements include global boundaries, local boundaries, resources, population and impacts. Ultimately global limits form the outermost boundary for humanity’s carrying capacity. However, this level of analysis may not be the most appropriate scale for measuring population carrying capacity. Many authors subscribe to more localised boundary delineation within which to define smaller populations.
Figure 11. Carrying capacity modelling can be encapsulated in a simple input-output diagram. Resource inputs and impact outputs are positioned both within local and global boundaries as they can potentially occur at both scales. As Durham[10] points out, “[l]imits exist in both the resource and sink functions of the environment.”