ISSUES OF SUSTAINABILITY

Revised 1 March 2025

"The point is not to see who may be the more correct, but to see the areas which will be particularly vital in the future and also to note some of the profound moral, ethical, and human questions which will be raised" - Sir George Thomson

Energy, production, and consumption are inextricably connected. Although the human constructs of money and debt have facilitated transactions and purchase of both energy and materials used in the production of goods and services (Graeber 2014), it is ultimately energy, the prime mover, which enables and drives production which provides our goods and services for consumption (Smil, 2017). Energy is subject to the Laws of Thermodynamics, and it is these laws and not theories of economics which dictate the limits of production and consumption and subsequent viable pathways in a transition from fossil fuels to sustainable energy sources and infrastructure. 

Although the future is unpredictable, there are nonetheless some aspects of the future we can be assured of with a degree of certainty. These include constraints on fossil fuels and solar based energy, mined minerals, and resources provided by ecosystems. We are able to make reasonable estimates now of what these constraints will be in the future. Any future scenario that we visualise should take these constraints into account. We should not extrapolate future scenarios based on technology that is currently feasible, but not necessarily viable when applied at a global scale without hidden subsidies of fossil fuels. Backcasting is a process which visualises future scenarios we would like to have after taking into account resource constraints. Backcasting then reverse engineers the possible pathways to the future back to the present. By reverse engineering viable future scenarios, necessary policies and actions which are common to all pathways become patently obvious. There are many pathways to the future and not all pathways are desirable. Backcasting, as opposed to forecasting, avoids dead end pathways. 

Figure 1 below maps growth in our human population and use of resources, including energy, from the past to the present and projects alternative pathways into the future. 

Figure 1: Alterative pathways into the future (Johnstone 1978)

Pathway A shows continuing growth into the distant future. This pathway is an impossibility. Non-renewable energy sources such as oil, coal, gas, and shale are finite and the surface area of our planet Earth is also finite. Our human population and economy simply cannot continue to grow forever, and because humankind is totally dependent on using energy for survival, our species will either eventually become dependent on using renewable energy resources or face extinction. At some stage in the future there will be a transition from growth to either a steady state or a decline and eventual collapse to extinction. Possible future paths include Pathway B which transitions smoothly from growth to steady state without any decline, Pathway C which declines from growth to a lower level of steady state, and Pathway D which collapses from growth to extinction. 

The actual level of steady state that is possible as depicted by Pathways B and C depends on the availability of renewable energy and mineral resources, the level of human population, and the carrying capacity of our ecosystems on Earth. There would be fluctuations in the level of steady state because regardless of whether future society is based on a market or planned economy or a mixture of both, there are likely to be periodic runs on the use of resources which need to be curbed and reeled back in. 

Whatever the overall level of steady state might be, there will be a gradual and inevitable decline in that level because it is physically impossible to 100% recycle the mineral resources that we are currently reliant on using in a technological society. As time progresses, it will become increasingly energy expensive to extract mineral resources from the ground. The peak production process that applies to extracting oil and other non-renewable energy sources from the ground also applies to mineral resources used in a technological society. 100% recycling is possible in natural ecosystems, so an inevitable decline of a technological society might ultimately result in a return to a hunter-gatherer society with a much-reduced population in the far distant future. As Nicholas Georgescu-Roegen (1971, p. 304) has put it, every additional Cadillac today represents a reduction in the life support system of distant future generations. Ultimately Earth will face a fiery death when in a few billion years’ time the Sun will expand into a Red Giant. We need not dwell on the far distant future. Our immediate challenge is to confront a transition from fossil fuels to renewable energy in the here and now.  

Pathway C, a decline over a hump down to a lower level of steady state, is more likely than a gentle transition from growth to steady state as shown in Pathway B for the following reasons. Humankind currently faces a double whammy. To avoid severe consequences of climate change, we need to curb our use of fossil fuels which adds greenhouse gases to the atmosphere. In our current industrial society we are reliant on using high-grade energy, so we need to transition to renewable energy sources. Setting up alternative infrastructure that provides and supports renewable energy will require additional use of fossil fuels at the very same time that we need to curb our use of those fossil fuels. In the long run, viable renewable energy source systems need to be able to maintain and replace themselves in order to be truly sustainable, but renewable energy systems are initially unable to bootstrap themselves through a transition without assistance of fossil fuels in the short-term. 

There are already indications that we have reached the stage of peak conventional oil where the rate of conventional oil production has started to decline. Ideally, humankind needs to divert the use of fossil fuels from unnecessary consumption to that of investment in renewable energy. However, regardless of voluntary curbing of the use of fossil fuel on consumption, peaking of all forms of fossil fuels will increasingly limit the rate of supply of fossil fuels in the future. Delays in enabling a transition from fossil fuels to renewable energy can only but exacerbate the difficulties of transition over time. 

A critical question is whether we can simultaneously curb our generation of greenhouse gases and transition to non-renewable energy. Given our response over the last 50 years to early warnings of climate change and the consequences of peak oil, there are good reasons for limited confidence that both targets will be met. Given the multiplicity of information and data from diverse and reliable sources of information, there is a high possibility that the future before 2100 will be strife for millions around the globe. Society has ignored warning signals about both climate change and peak oil over the past 50 years and tends to respond only to emergencies. It is likely that insufficient action will be taken to fully address the issues of climate change, peak oil, and the need for zero population growth. 

The elephant in the room is population growth. The need to curb population growth has been ignored and shelved. Steady state for humankind requires zero population growth (ZPG). If all countries were to immediately adopt a policy of ZPG, then the global population would continue to grow for a number of decades despite the low growth and even declines in the natural population of several developed countries. Continued increases in population during a transition from fossil fuels to renewable energy can only but result in a Sisyphus-like undermining of any efforts for a smooth transition. 

Continuing with a focus on Pathway C, renewable energy currently includes hydro-electricity, phytomass (plant material), wind power, solar energy concentrators, photovoltaic cells, geothermal power, and tidal waves. The scale and extent that each of these energy systems can be used by future human settlements depends on the availability of mineral resources needed to create these energy systems, the resulting net energy produced by these energy systems, and the convenience of the form of energy that is generated. For example, hydrogen is a convenient concentrated form of energy suitable for transport, but the production of hydrogen does not result in net energy because it takes more energy to produce than the energy content available in the hydrogen. Hydrogen is a convenient carrier of energy, but is not an additional energy source independent of the energy required to produce it. 

Nuclear fission as an energy source involves ethical issues. We bear a responsibility to future generations of humankind and other species not to endanger their existence and leave them a heritage of nuclear waste that will have to be guarded for centuries. Some energy researchers advise against ruling out nuclear energy. New Zealand is fortunate in that the use of nuclear energy is unnecessary because New Zealand already has a high level per capita of hydro-electricity, high potential for wind power, and potential to expand its current generation of geothermal electricity. Should our current level of technology improve in the future to include nuclear fusion, then the carrying capacity and the consumer level of life could both increase, but within limits.  

Humankind continually comes across limits in every sphere of life. The ultimate peaking and decline of easily accessible high-grade energy fossil fuels and mining of minerals are but some of many limits. A crisis can develop when humankind does not accept there are limits. Humankind induced climate change is an example. Limits exist and we need to accept them and act accordingly for humankind to continue to survive in future millennia. A growth philosophy has enabled development of civilisation in the past. Further development does not require further growth. We now need to cast aside a growth philosophy which ignores the consequences of limits.  

We, our children, and our grandchildren are privileged to be living in a period of transition that is unparalleled in the entire history of humankind. The decisions and actions that we have made in the past and the decisions and actions that we will make over the next number of decades have and will limit the options of current and future generations. We need clear visions of pathways in a transition from growth to steady state. We must plan for a sustainable future that we are able to have in the long term rather than continue on our current growth pathway which is no longer viable. Hartmut Bossel in his 1998 book Earth at a Crossroads: Paths to a Sustainable Future makes the following comment: 

"The many alternative visions of sustainable futures that have been published in the past three decades all agree - with minor variations - on the fundamental principles and processes … This is a remarkable result, and it is all the more remarkable as the different authors have arrived at these alternative visions independently of each other - in different countries, at different times, under different circumstances, in different languages. It can only mean that there is a common body of facts, knowledge, and ethical principles from which consistently the same conclusions can be drawn. "

A vision of a society that we are able to have in the long term can be gained by compiling and comparing the characteristics or attributes of a growth society versus a viable sustainable society which is subject to energy and material constraints. In 1979, my compilation of the attributes of a growth versus a sustainable society was published in the international journal Urban Ecology. I have compiled an update in Table 1 below: 

Table 1: Attributes of Growth versus Steady State Settlements (Johnstone 2025)

The economic philosophy of a sustainable society will be very different from that of a growth society. A sustainable society will accept limits and the purpose and emphasis of production will be on the maintenance and wellbeing of everyone in society with equitable distribution of production. 

A sustainable society will allow development without physical growth of material and energy flows and population. All energy must be renewable and all materials must be recyclable. The per-capita use of energy and materials will be less than what it is now consumed in the developed countries. 

A sustainable society will need to be more self-sufficient and its technology will be more appropriate according to the level of energy and materials per-capita available for production. Technology will need to be more benign with less pollution which can be assimilated by the environment. Mass production will be replaced by artisanship. Food production using permaculture methods will involve everyone and will replace industrialised monoculture. A sustainable society would be more community oriented. 

In 1968, Constantinos Doxiadis published his book Ekistics: An Introduction to the Science of Human Settlements. In any highly complex field of study there needs to be a systematic form of classification. Ekistics provides a full and complete taxonomic system which facilitates the study of the physical, social, and organic nature of human settlements. I have modified Doxiadis’ Ekistics Relationship Matrix to incorporate the attributes of a steady state settlement. The modified matrix can be used as a check list and catalyst for identifying and developing objectives, proposals, and policies required to ensure long-term sustainability of human settlements. All policies would need to be mutually supportive without conflict. 

Table 2: Ekistics Relationship Matrix (Doxiadis 1968 modified by Johnstone 2025)