This research aims to identify, examine and compare
existing approaches to carrying capacity assessment and consider their
relevance to future spatial and infrastructure planning. It raises the
following questions: Which carrying capacity assessment models are best suited
for determining future sustainable land-use and community infrastructure? What
gaps in existing research need to be addressed? Is it possible to achieve a
practical model for assessing regional human carrying capacity?
This research aims to add practical application to what are
currently well-intentioned but untested emerging societal aspirations
concerning carrying capacity assessment. Basic questions such as, “How much
land does a population require for its minimum resource requirements?” are
currently not easily measurable. It is anticipated that the carrying capacity
model developed through this research, can more accurately define the variables
inherent in this question, and more clearly articulate possible outcomes. For
example, the model might suggest that a certain region’s population may
currently be within the carrying capacity of its landscape for one year of
average production given existing consumption patterns, but perhaps it may be
over-capacity if longer timeframes or different consumption patterns are
applied. Carrying capacity assessment thus offers a dynamic tool for
ascertaining population thresholds and potential future population distributions,
as well as providing important guidelines for living within these physical
limits. As such, it has the potential to influence urban and rural planning
policy at all levels of government. It can also be useful for researchers and
educators in highlighting system boundaries and physical limits to design
proposals. Perhaps above all else, it can help individuals and local
communities to more clearly define lifestyle changes necessary to ensure more
resilient and sustainable societies in the future.
One productive outcome of this research is to develop an
easily accessible carrying capacity model, the Carrying Capacity Dashboard, in
order to better define and publicise how the process of carrying capacity
modelling can operate and to give users a real experience of testing various
carrying capacity parameters. Carrying capacity analyses, by definition, are
reflective of a particular piece of land at a particular time, which invariably
possesses its own unique physical characteristics, resources and environmental
responsiveness. Consequently, the model generated as part of this research aims
to estimate maximum population thresholds based on the unique biophysical
characteristics of specific geographical regions within Australia.
The model may account for various societal and agricultural systems, environmental
protection processes and a range of lifestyle choices such as energy, water and
food consumption. Given the complexity of the input data, a definitive carrying
capacity population number is never likely to be achievable. However, it is
possible to offer an approximate figure or range of figures as long as the
variables are clearly articulated at the same time. For example, it may be
possible to state that the Southeast Queensland region
has a carrying capacity of say, two hundred thousand people, assuming that they
ate a certain diet and farmed a certain way. The advantage of this approach is
that these variables can also be dynamically altered and the impacts on
carrying capacity observed.
This research primarily aims to explore quantitative
approaches to carrying capacity assessment, using mathematical formulae to
generate a numeric result.[iii] Given
the difficulties of incorporating wide ranging and ever-changing variables, it
is acknowledged that the measurement of carrying capacity is a complex task. In
fact Livi-Bacci[iv] argues
that, “the identification of carrying capacity presents so many conceptual
difficulties as to be virtually useless for practical purposes.” However, there
already exist several workable examples of carrying capacity assessment models so
in disproving Livi-Bacci’s assertions, the objective of this research is to
synthesise and refine these methodologies into an approach suitable for practical
purposes. In summary, the processes proposed for this research involve
refining existing carrying capacity assessment methodologies, compiling
existing data, constructing the model, testing it and publicising it.
There are two key steps that populations must take in order
to live within their long-term bio-regional limits - carrying capacity
assessment and maintenance. It thus follows that the scope of this research is
bound by these twin aspects. From an assessment perspective, populations need
to make ongoing assessments of both their landscapes capabilities and societal
needs; and a fair and sustainable balance must be struck. Secondly, populations
need to maintain a size which is far enough below the carrying capacity of regional
biophysical limits to allow for productive variability from year to year. The
implications for carrying capacity maintenance range from migration to birth
control to re-localisation.
From a land-use planning perspective, the scope of this
research includes all the systems involved in the way we interact with our
environment. As such, it comprises a range of settings such as urban, rural and
environmental planning; as well as societal systems that underpin our society
such as governance and the economy. While the relationship between the land and
its people already forms the basis for existing land-use planning, a carrying
capacity focus also offers a way to better measure the relationships between
these aspects. In fact, it is suggested that the assessment of these
biophysical constraints should form the first step in future land-use planning
practice. The practical steps involved in this process of carrying capacity
assessment involve quantifying these constraints, analysing them collectively,
and then making predictions about their behaviour.
The success and validity of future land-use planning
necessitates the inclusion of whole systems carrying capacity assessment models
estimating the ability of a landscape to produce the resources necessary for a
certain population as well as its capacity to assimilate any subsequent waste.
However, a thorough incorporation of these dual components is ultimately beyond
the scope of this research. The focus, therefore, has been largely on the first
stage of a society’s resource utilisation, its resource production. This
research argues that in a closed system (which carrying capacity assessment
implies) there is a linear progression from resource production to resource
usage (consumption) to resource assimilation (waste) so notwithstanding extreme
environmentally destructive behaviour, the amount of resource assimilation is
dictated by the amount of resources produced. Dilworth[v] explains
this predicament another way by pointing out that society’s, “quantity of waste
cannot be reduced without reducing the quantity of materials used.” This is not
to suggest that the assimilation of waste is unlikely to have an impact on the
carrying capacity of a given landscape; and it also does not mean to imply that
a circular pattern of resource utilisation, where waste is recycled back into
resource productivity, is not preferable to an entirely linear one. Rather, it
merely observes that in a closed system, the degree of resource wastage, destined
for environmental assimilation, is largely dependant on the degree of resource
production, so is deemed to be of secondary importance.
[i] REDLAND CITY COUNCIL (2010)
Redlands 2030 Community Plan.
[ii] GARDINER, P. (2009) Both
sides say use it or lose it. Noosa News.
Noosa News.
[iii]
Quantitative assessment involves numeric calculations whereas qualitative
analysis relies on theoretical formula (such as I=PAT) to illustrate carrying
capacity concepts.
[iv] LIVI-BACCI, M. (1992) A Concise History of World Population, Oxford,
Blackwell.
[v] DILWORTH, C. (2010) Too smart for our own good: the ecological
predicament of humankind, Cambridge, Cambridge University Press.
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