Why we need to assess our carrying capacity

There are clear signs that society is threatening the biophysical limits of our shared environment and that the size, distribution and behaviour of the population is to blame. The seven billion-strong global human throng is exerting such pressure on our existing societal and environmental systems as to suggest a re-evaluation of existing approaches to the way in which land and resources are managed and to the very structures that allow these problems to escalate. We need to fundamentally reshape our land-use planning practices to align with the biophysical constraints of the landscape. To this end, we need the tools to quantify these constraints, analyse them collectively, and then make predictions about their behaviour to inform planning decisions. This practice defines the process of carrying capacity assessment. 

The question of global overpopulation has challenged the world’s sociologists since Thomas Malthus raised the prospect over 200 years ago. Malthus [i] argued that while human population potentially grows exponentially, the resources required for human survival remain relatively finite. To date, society has largely managed to produce the resources necessary to feed, house and clothe the majority of the earth’s inhabitants, though in vastly differing degrees of comfort, and Malthusian sceptics[ii] argue that his predictions of over-population have not eventuated because advanced technology and the use of high-energy fossil fuels have allowed for a significantly expanded resource-base. However, this mode of industrialised production and consumption has proven costly, with world-wide environmental degradation, resource depletion and social inequities escalating, and an ever-increasing global population serving to magnify the problem.

A revision of current energy-intensive consumption patterns is essential if society is to address the global problems we now face. For instance, in order to accommodate the likelihood of a lower energy-intensive future, it is becoming apparent that society’s resources will increasingly need to be produced and accounted for, much closer to where they are to be used. New land-use strategies need to be developed in order to cope with the challenges ahead and a re-localised system of resource usage is one potential systemic change that may facilitate more sustainable future lifestyles. For instance, Vail[iii] argues that local production and consumption of resources engenders greater environmental and ethical responsibility in local populations because impacts are often more immediately obvious and behavioural correctives, more willingly undertaken. Accordingly, in order to ensure more equitable and sustainable future land-use patterns we must endeavour to directly link and limit populations to the regions which sustain them. It is envisaged that such an approach to population management would not only fundamentally question existing approaches to land-use planning, but to the very systems that define our society such as economics, governance and eduction. To this end, carrying capacity assessment methods that accord with whole-system and regionally-based design approaches need to be developed to inform planners, stakeholders and local inhabitants of sustainable land-use options.

Despite widespread awareness of worsening global environmental indicators such as species extinction and climate change, our current societal systems appear to conspire against taking meaningful corrective action. The dominant global economic paradigm is one of infinite growth, despite its implausibility on a finite planet with finite resources. At the heart of this problem is the widespread misapprehension of system divisibility; that our economy can act independently from the physical environment (figure 1a); despite the fact that all resources, all people and all of society is set within a physical system. The environment is thus the biophysical context that encapsulates and supports all other systems. Nested inside the physical sphere are society’s socio-cultural systems, of which the economy, being a subset of the society, is but one part amongst a number of other systems including education, health and governance (figure 1b).


Figure 1a. (left): Intersecting environmental-societal systems - an unrealistic representation of the whole. An example of its use is in the Australian Government’s recent population strategy. [iv]
Figure 1b (right): Nested systems - a more accurate illustration of the relationship between economic, societal and environmental systems. An example of this model can be found in the Sunshine Coast Regional Council’s Sustainability Advisory Panel report. [v]
 
Given the dependence of societal systems on biophysical health, it is incumbent on land-use planning practice to more clearly define the extent to which society is able to encroach into the biophysical sphere. However, at present, most local regions possess neither the tools nor the know-how to assess the productive capacity of their own precincts. To this end, carrying capacity assessment offers a way to assess our resource needs and also determine how best to meet these needs in the future. This process establishes direct causal relationships between a specific landscape, timeframe and people, and inherently links these aspects to systems of land usage and social function.
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[i] MALTHUS, T. R. (1959) Population: The First Essay, Michigan, University of Michigan Press.
[ii] LOMBORG, B. (2001) The Skeptical Environmentalist: Measuring the Real State of the World, Cambridge, Cambridge University Press.
[iii] VAIL, J. (2006) Envisioning a Hamlet Economy: Topology of Sustainability and Fulfilled Ontogeny
[iv] This AUSTRALIAN GOVERNMENT (2011) Sustainable Australia - Sustainable Communities. A sustainable population strategy for Australia. Barton, Department of Sustainability, Environment, Water, Population and Communities.
[v] SUNSHINE COAST REGIONAL COUNCIL (2009) Sustainability Advisory Panel Minutes. Nambour.