NBS | Sustainability: Sustainability... more questions than answers?

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Sustainability... more questions than answers?

Often, the arguments for sustainability are presented with a closely focused agenda. Here, NBS Technical Editor, Norman Carless, takes a step back and questions the principles and definitions of this expansive topic.

Not so very long ago, the keyword in the environmentalist's jargon was 'green'. Today, 'green' is old hat; environmental watchdogs have a new, much over-used buzzword – 'sustainable'. But what does it mean? Attempts to bring concepts such as conservation, preservation and recycling under the umbrella of 'sustainable' have led to confusion and misunderstanding. For instance, the term 'sustainable development' should mean development (1) at a continuing steady rate – but is that what users intend it to mean?

"Sustainability means whatever a politician says it means to support their agenda at any time.'"

Without reference to a dictionary, this definition, coined by a colleague, is to my mind the most accurate I have come across while researching this topic. The same line of thought is evident in a poignant lecture given by writer and architectural commentator, Martin Pawley, at the Building Audacity Conference in 2000 (2). Quoting Alastair Sim, 'We are all ruled by dead ideas, but it is only when an idea has become utterly meaningless that it can be used in politics', Pawley cites the rise of 'sustainability' as living proof of this.

However, rather than get bogged down in political argument and debate, let's see if the dictionary (3) can give us a clearer picture of what 'sustainable' means.

Taking one step back, the verb 'sustain' (used transitively) means 'Maintain or keep going continuously (an action or process)', and the adjective 'sustainable' means 'Able to be maintained at a certain rate or level.'

Clearly, extracting materials from the ground for use as fuel (uranium, coal, natural gas, oil, peat, etc.) or in manufacturing processes (e.g. oil, metal ores) is not sustainable because, sooner or later, the materials will run out. Reducing the rate of usage, and hence the rate of extraction, of limited resources will delay the inevitable but not prevent it.

The question is: Does it matter? In one sense, it doesn't. Reserving oil and natural gas supplies for our grandchildren so that they can reserve them for their grandchildren, so that they can reserve them for theirs ... is a futile gesture. What does matter is the effect that using these materials has on the environment. Burning fossil fuels releases carbon dioxide and other 'greenhouse gases', which pollute the atmosphere and contribute towards global warming, and this alone should be sufficient reason to curtail their use and seek alternative sources of energy. Even in cases where the raw material is plentiful, e.g. sand (silica), the consequences of continuous extraction (coastal erosion, landscape disfigurement) cannot be ignored.

Which brings us back to the dictionary and the second part of the definition of 'sustainable' – 'not leading to depletion of resources or degradation of the environment' – which relates specifically to development, agriculture, etc. This definition brings to mind another term frequently regarded as interchangeable with 'sustainable' – 'renewable'. This is hardly surprising when the dictionary defines 'renewable' as 'Of a source of material or energy: not depleted [exhausted] by utilization.' Perhaps the most frequently cited example of a renewable material is timber. A tree is cut from the forest and converted into useable forms, such as constructional timber and wood pulp for paper making. Once the tree is used, it is used – it cannot be replanted; so individual trees are not renewable. But, a new sapling can be planted to take its place and will, in time, provide a source of timber or pulp or whatever. Thus the supply is not depleted, and timber can claim to be a 'renewable' material. The WoodLot Glossary (4) defines 'sustained yield timber management' as 'management of a forest property for continuous production of timber with the aim of achieving an approximate balance between net growth and harvest'. However, the ethics of even this seemingly simple concept are hotly debated.

Whilst raw materials such as iron ore and aluminium ores are not renewable, the metals produced from them can be recycled indefinitely without losing any of their properties. According to 'Waste Online' (www.wasteonline.org.uk), around 70% of iron and steel scrap is recycled annually, requiring 25% of the energy needed to produce steel from iron ore. Recycling aluminium requires an even smaller percentage (about 5%) of the energy needed for primary production. In both cases, CO₂ emissions are commensurately reduced. Does this mean that recycling qualifies as a 'sustainable' activity?

On the subject of energy, it should be obvious that development can not be sustained (i.e. maintained) at present levels if fuel supplies in the form of coal, natural gas and oil run out. Other natural sources, such as wind and solar energy, can be harnessed, but – can they provide a total solution? For more information on this subject I can do no better than refer you to a publication that will, as the saying goes, tell you 'everything you need to know about sustainable energy, but were afraid to ask'. Sustainable energy – without the hot air, by David J C MacKay, is freely available at www.withouthotair.com. As former Environment Minister, Michael Meacher MP, has said 'It should be a 'must read' not only at home and in industry, but on each Government Minister's desk, and not just in the UK.'