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[ Definitions ] Sustainable Development ] Indicators of Sustainable Development ] Sustainable Agriculture ] Integrated Systems ]

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Petronas Twin Towers, Kuala Lumper


O'Riorden (1985) commented on the difficulty of  defining sustainability, describing its definition as an:

'Exploration into a tangled conceptual jungle where watchful eyes lurk at every bend'

Spedding (1996) commented that perhaps this was the reason for:

'The remarkable number of books, chapters and papers, that even use 'sustainable' or 'sustainability' in the title but do not define either term'

Wilson (1992) stated:

'The raging monster upon the land is population growth, in its presence, sustainability is but a fragile theoretical construct'

Definitions of sustainability

The definitions given below encompass all aspects of this subject. The areas of sustainable agriculture and sustainable development are dealt with in more detail later in the subject:

1.   Brundtland (1987): This is the most commonly quoted definition and it aims to be more comprehensive than most:

Sustainable development is development that meets the needs of the present without compromising the needs of future generations to meet their own needs.

It contains within it two key concepts:

The concepts of needs, in particular the essential needs of the worlds poor, to which overriding priority should be given, and:

The idea of limitations imposed by the state of technology and social organization on the environments ability to meet present and future needs.

2.   Harwood (1990):

Sustainable agriculture is a system that can evolve indefinitely toward greater human utility, greater efficiency of resource use and a balance with the environment which is which is favourable to humans and most other species.

3.   Pearce, Makandia & Barbier (1989)

Sustainable development involves devising a social and economic system, which ensures that these goals are sustained, i.e. that real incomes rise, that educational standards increase, that the health of the nation improves, that the general quality of life is advanced.

4.   Conway & Barbier (1990) from 1,2 & 3:

We thus define agricultural sustainability as  the ability to maintain productivity, whether as a field  or farm or nation. Where productivity is the output of valued product per unit of resource input.

5.   Daly (1991) then argued that:

Lack of a precise definition of the term 'sustainable development' is not all bad. It has allowed a considerable consensus to evolve in support of the idea that it is both morally and economically wrong to treat the world as a business in liquidation. 

Pause for thought....... The world, a business in liquidation, would you consider this a sensible way for international powers to approach the concept of sustainability (at any level), what are the reasons for your answer?

6.   Heinen (1994)

No single approach to 'sustainable development' or framework is consistently useful, given the variety of scales inherent in different conservation programmes and different types of societies and institutional structures

7.   IUCN, UNEP, WWF (1991):

Sustainable development, sustainable growth, and sustainable use have been used interchangeably, as if their meanings were the same. They are not. Sustainable growth is a contradiction in terms: nothing physical can grow indefinitely. Sustainable use, is only applicable to renewable resources. Sustainable development is used in this strategy to mean: improving the quality of human life whilst living within the carrying capacity of the ecosystems.

8.   Holdgate (1993):

Development is about realising resource potential, Sustainable development of renewable natural resources implies respecting limits to the development process, even though these limits are adjustable by technology. The sustainability of technology may be judged by whether it increases production, but retains it other environmental and other limits.

9.   Pearce (1993):

Sustainable development is concerned with the development of a society where the costs of development are not transferred to future generations, or at least an attempt is made to compensate for such costs.

Pause for thought.......List 3 historical events or actions where the costs have been transferred to future generations

10.   HMSO (1994):

Most societies want to achieve economic development to secure higher standards of living, now and for future generations. They also seek to protect and enhance their environment, now and for their children. Sustainable development tries to reconcile these two objectives.

Analysis of sustainability

Riley (1992) pointed out that the level of analysis of sustainability is important and quoted the following table:

Analysis of sustainability
Level of analysis Typical characteristics of sustainability (cumulative) Typical determinants of sustainability
Field/production unit Productive crops & animals; Conservation of soil & water; low levels of crop pests & animal diseases Soil & water management; biological control of pests; use of organic manure; fertilizers; crop varieties & animal breeds
Farm  Awareness by farmers; economic & social needs satisfied; viable production systems Access to knowledge, external inputs and markets
Country Public awareness; sound development of agro-ecological potential; conservation of resources Policies for agricultural development; population pressure; agricultural education, research & extension
Region/continent/world Quality of the natural environment; human welfare & equity mechanisms; international agricultural research & development Control of pollution; terms of trade; distribution

Pause for thought......Before moving on to the next section, see if you can categorize different levels or types of sustainability

Types of Sustainability

There are two commonsense propositions that would probably command general support, before categorizing the different types of sustainability:

  1. A sustainable system or process must be based on resources that will not be exhausted over a reasonable period (sometimes expressed as the 'long term')

  2. A sustainable system or process must not generate unacceptable pollution externally or internally

Biological sustainability

No individual life form can be sustainable indefinitely, since all must die at some point in time. Therefore:


Preservation of individual life is only possible for limited periods (limited sustainability)


Individual species, ecosystems and habitats can be sustained as they involve reproductive and other essential processes - without which they would cease to exist


However, many of these entities change and evolve as a result of such processes therefore:


Sustainable processes does not necessarily lead to sustainable entities (i.e. precisely as they were originally)


Most biological systems have physical components, therefore there is considerable overlap between the use of biological and physical resources 

Pause for thought........List 5 points in an agricultural system where the actions of the farmer directly effects  biological sustainability. 

Sustainable resource use

Newly manufactured fence posts, but are they from a sustainable wood supply?

Resources such as water and energy can be used up, but never destroyed. They may be changed in form, be recyclable or difficult to recapture. There is a difference between using a resource and using it up. For example, the countryside. Viewing the hills in the Lake District is not using up the resource, walking in the hills may (eventually) destroy them. The diagram below illustrate the flow of resources through a 'typical' rural community.


Source: Pretty, J. N. The Living Land (1998)

Pause for thought............The arrows in the  flow chart above, outline the flows of money through the rural sector, can you suggest any free resources the farmer receives, and of what use are they?

Non living resources

Some resources are limited, other resources if not used now, will not  remain. The most obvious example being sunlight. If the solar radiation received today is not trapped and utilized, it will not be available tomorrow . Nor will the rate that it is used today effect the amount that can be used tomorrow. The sun however is not an infinite resource and is slowly (albeit very slowly) running down. Non-living resources may largely remain intact, though they may change greatly in form (consider soil erosion, radiation loss and weathering of rock).  Resources such as fossil fuels are totally changed when used and cannot be recreated on any reasonable time scale. But they serve no purpose if left unused. The use of fossil fuels is entirely necessary to discover and exploit other resources for energy production. They make possible the construction of dams for hydropower and windmills for wind power. In other words, we are using the limited resource to find the means not to use, or at least limit its rate of use in the future.

CLICK HERE for an American view on renewables

Pause for thought.......If a resource is limited, is there any benefit of leaving it totally unused?

Gas and petrol are both derived from unsustainable resources

Living resources

Living resources do not remain static. A dairy cow which is not milked may not provide any milk in the future and may eventually die and be unavailable for any purpose.

The use of living resources may have to be considered over a relatively short period or be related to populations (plant and animal) capable of reproduction. This has given rise to the concept of sustainable harvesting, taking only such proportion of the population as can be continued over time, depending on reproductive rates in animals and seed numbers in plants

Pause for thought.....List 2 industries that claim to practice sustainable harvesting

Consider the fact.........All living things must eventually die: thus, a tree not used as a resource  will eventually die and decay - liberating the same amount of CO2 as if it had been burnt.

Economic and social sustainability

Economics is about the efficient use of resources, usually expressed in monetary terms. In this sense, the theories regarding sustainable use of resources can be applied to economic sustainability, except that, in monetary terms, one resource can generally substitute for another. The concept of economic sustainability is subject, on all levels, to different inputs and outputs. The economic sustainability of a farm is subject to the viability of, and markets for, an enterprise or product. The economic sustainability of a nation is subject to the whole economy on local, national and international level. 

It is often argued that something is not sustainable if it depends on unacceptable practices, for instance, in the 18th  Century it was acceptable to send small boys up chimneys, cheap but morally wrong and socially unacceptable. 

The subject of economic and social sustainability is alluded to in great detail in the outside links in the sustainable development section.

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[ Definitions ] Sustainable Development ] Indicators of Sustainable Development ] Sustainable Agriculture ] Integrated Systems ]

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