What Is Sustainability All About?


There are many definitions of sustainability, nearly all derived from the Brundtland report definition “meeting the needs of the present without compromising the ability of future generations to meet their own needs”. Despite what many mistakenly think, this is a social rather than environmental objective.

Here I avoid the definition debate and propose a simple sustainability goal statement of enduring wellbeing. This goal describes a societal condition, which is a system state. All system states are transient, they change over time. Accordingly, the study of sustainability needs to be a study of behaviour over time. Because human societies are complex systems that are part of even more complex natural systems, this study can only be meaningfully undertaken using systems thinking and systems analysis. This site uses these approaches to understand where we are and where we are going.

There are two dimensions to the sustainability problem:

·       The purely social interactions that affect human wellbeing; and

·       The interactions between the human world and the biosphere which we inhabit with all other life on earth, and which provides our material necessities.

Together these interactions form a global socio-ecological system.

The dynamics (meaning simply the behaviour over time) of this system will determine whether humanity achieves the sustainability goal of enduring human wellbeing or not. 

This figure is a causal loop diagram which illustrates cause and effect in a system. It is to be read as follows. Each arrow illustrates either a positive or negative causality between the variables, i.e an increase over time in variable X leads to an increase (+) / decrease (-) in variable Y.

The system in question is the global socio-ecological system, shown here in a highly simplified way as three interconnected subsystems: Society, Economy and Environment.

The well known Brundtland definition of sustainability is:
“meeting the needs of the present without compromising the ability of future generations to meet their own needs”. Here I adopt a briefer description that amounts to the same thing: “Enduring human wellbeing”. Thus, human wellbeing is the objective variable in the system map. It should be read as follows, from the left.

Human wellbeing is a function of living standards, the nature of the society in which a person lives (social quality) and an individual’s ability to have a level of control over their life (empowerment). The empowerment of women in particular is critical to promoting the demographic transition that is necessary to stabilise the global population. Living standards and the level of collective wellbeing combine to determine the basic level of functionality in the society, which is a pre-requisite to improved social quality (cohesion, inclusion, economic security and empowerment). Hence there is reinforcing feedback between human wellbeing and social quality – as one improves (or deteriorates) so does the other (Loop R1).

The basic material standard of living is a function of the economy – more and better jobs and income improve living standards. As the standard of living increases (or decreases) the economy produces more (or fewer) goods and services. Traditionally, higher living standards have also led to population  increases. There is also reinforcing feedback in this loop (Loops  R2 and R3) – higher living standards lead to more population and more economic production – although in modern times this is offset by the demographic transition, i.e. the tendency for fertility rates to decrease with increasing living standards (Loop B1). People of course, are both creators of economic demand, and of economic production. These reinforcing tendencies result in exponential growth, which is what we have seen in the population and economic data over centuries. What is not well understood is that reinforcing  eedback can also lead to exponential decline.

So, we have so far shown that enduring human wellbeing is dependent on interactions within the social sub-system and between the social and economic sub-systems. But of course, the economy sub-system is totally dependent on the non-human biotic and abiotic world. Economic production simultaneously uses and depletes natural resources (Loop B2). This is balancing feedback, meaning that continuing natural resource depletion will eventually dampen economic production. While renewable resources (e.g. timber) can be regenerated, non-renewable natural resources (e.g. fossil fuels) cannot. The combination of rising population and economic production converts natural habitat to (predominantly) human use, having an adverse effect on  iodiversity
(Loops B3 and B4), and therefore the natural resources available for economic production. Economic production also produces pollution and waste which impacts biodiversity (Loop B5). All of these economy-environment interactions involve balancing feedback, i.e. there are limits to both population growth and economic production that will arise from continuing exploitation of environmental resources.

We live in a complex global socio-ecological system, made up of a myriad of geographically separate but interconnected sub-systems, all of which exhibit feedback. The variable that is most problematical at present is carbon pollution, which through the feedbacks illustrated here, affects the entire world. However, population growth, natural resource depletion, loss of biodiversity and pollution also cannot continue forever without adversely affecting living standards and wellbeing, i.e. they are unsustainable. These are the key dependencies that underpin society, and they remain inadequately managed by humanity some 35 years after the warnings in the Brundtland report.

Sustainability is a quest for equilibrium in the global socio-ecological system, which requires (as the economist Herman Daly told us forty years ago): population to stabilise, natural resources to be used at a rate that is replenishable (or substituted with renewable ones), pollution to be limited to rates that can be assimilated by nature, and biodiversity to be conserved. The society-economy sub-system on which we focus is completely dependent on natural resources. Humanity will either grasp this reality, or suffer the consequences

In these pages I seek to reflect on each of the elements in the system diagram above. These reflections emerge from my professional experience, research, the literature, collaboration with colleagues, and (of course) endless debate and discussion with friends and family.

Some of the common sustainability jargon

Complex systems

“Complex systems are composed of a large number of active elements whose rich patterns of interactions produce emergent properties that are not easy to predict by analysing the separate parts of the system.” (Elinor Ostrim 1999).

Further reading here

Socio-ecological systems

C.S (Buzz) Holling pioneered the work that forms the basis of the present day research into socio-ecological systems (SESs), i.e. “linked systems of people and nature”. His initial work on non-linear dynamics in ecosystems led to the seminal 1973 paper “Resilience and stability of ecological systems” Holling was the founder of the Resilience Alliance in 1999, a research collaboration focussing on the dynamics of social-ecological systems. Further reading here

Ecosystem Services

Excerpt from the Millenium Ecosystem Assessment

“Ecosystem services are the benefits peopleobtain from ecosystems. These include provisioning services such as food, water, timber, and fiber; regulating services that affect climate, floods, disease, wastes, and water quality; cultural services that provide recreational, aesthetic, and spiritual benefits; and supporting services such as soil formation, photosynthesis, and nutrient cycling. (See Figure A.) The human species, while buffered against environmental changes by culture and technology, is fundamentally dependent on the flow of ecosystem services.”

Systems Thinking

“A system is an interconnected set of elements that is coherently organised in a way that achieves something. If you look at that definition closely for a minute, you can see that a system must consist of three kinds of things: elements, interconnections, and a function or purpose.”

Donella Meadows

Systems thinking reflects the fundamental understanding that systems exhibit complex behaviour and feedback, potentially giving rise to counterintuitive outcomes from any specific policy action.

Further reading here

Causal loop diagrams

A causal loop diagram is a graphical depiction of cause and effect that identifies the dependencies and feedback in a system.

For more on causal loop diagrams go here

Millennium Ecosystem Assessment

The Millennium Ecosystem Assessment (MA) assessed the consequences of ecosystem change for human well-being and the scientific basis for action needed to enhance the conservation and sustainable use of those systems and their contribution to human well-being.

The MA involved the work of more than 1,360 experts worldwide. Their findings, contained in five technical volumes and six synthesis reports, provide a state-of-the-art scientific appraisal of the condition and trends in the world’s ecosystems and the services they provide (such as clean water, food, forest products, flood control, and natural resources) and the options to restore, conserve or enhance the sustainable use of ecosystems.

For more on the MA go here

Ecological Footprint

The ecological footprint is a measure of human demand on the Earth’s ecosystems. It is a standardized measure of demand for natural capital that may be contrasted with the planet’s ecological capacity to regenerate. The ecological footprint concept and calculation method was developed as the PhD dissertation of Mathis Wackernagel, under supervision of William Rees at the University of British Columbia in Vancouver, Canada.

The ecological footprint process is now maintained by the Global Footprint Network, a non-profit organisation.

For more on the ecological footprint go here.

Demographic transition

The demographic transition denotes the change from high to low birth and death rates as nations develop to modern industrialised economies.

For more on the demographic transition go here