8 ENGINEERING AND SUSTAINABILITY
A Sustainable Future – The Challenge for Engineering
Sustainable development is one of the biggest challenges facing engineers in the 21st century. Currently, industrial and economic development rely on the use of resources which will not last forever, and whose consumption may threaten the future of the planet. Sustainable development is about improving the standard of living across the world in a way that can be maintained in the long term. For example, it is pointless to dig a well to provide water for a village if the pump cannot be maintained when it breaks down, or if over-abstraction of the water results in the well drying up, or if the villagers do not have the skills or cannot afford to keep the well going. This example shows that sustainable development must take into account not only economic issues such as capital and maintenance costs, but also social and environmental factors. The recognition that there is more to a project than exclusively financial sustainability is sometimes called the ‘triple bottom line’ (economic, social and environmental).
Usually, engineers are driven by short-term economics at the expense of the other factors. This is short-sighted. The planet’s resources are finite; that is to say we have limited land, energy and water resources which must be shared amongst the earth’s population. It is estimated that if everyone on earth used the same amount of energy as someone living in the UK, we would need 8.5 planets to live on! Clearly this situation is not sustainable.
Engineering has played a big part in the way that
energy has been produced and used. It is now widely recognized that human-induced greenhouse gas emissions, mainly due to the combustion of fossilized hydrocarbons, are changing the composition of the atmosphere in such a way that the earth’s average global temperature will increase. The consequences of a global average temperature rise of even 2˚C will be profound and potentially disastrous: mass flooding due to a rise in sea levels, destruction of important ecosystems and food supplies, and the spreading of tropical diseases such as malaria. Yet, the physics of planetary temperature balance are nothing new; in fact, they were first understood by the renowned French mathematician, Fourier, almost 200 years ago. The primary use of hydrocarbons – molecules containing hydrogen and carbon, which can be combusted to release energy – is for energy; the energy that moves our cars and trucks, heats our homes and lights our offices. Oil, coal and natural gas, or methane, are the chief suspects, the unsustainable modern-day workhorses which help us do the tasks that would otherwise require manual labour.
The urgent challenges of sustainable energy production and use need to be met by engineers.
Firstly, energy demands need to be reduced to an absolute minimum. This will partly be through behavioural changes; for example, using the car as little as possible (or getting rid of it), but demand reduction will primarily be through the implementation of more efficient lighting, heating, cooling and transport technologies. Secondly, energy needs to be generated from sources that do not place further global warming gases in the atmosphere. Renewable energy sources, such as wind, tidal and solar power, have a big part to play, with nuclear power as a potentially important interim solution.
Another area where engineers have an important
role is in the way that materials are used. Most products are designed with a ‘cradle to grave’ life in mind, that is to say they begin as some raw material (for example, aluminium) and end up as a product (such as a drinks can), which is then discarded into a landfill site. A tremendous amount of energy and effort has gone into the manufacturing of the product, and at the end of its life it is no longer useful. This situation does not exist in the natural world, where decaying plant and animal matter becomes food for other plants, animals and organisms. Engineers should try to copy this ‘cradle to cradle’ idea, which is an approach where products are still useful at the end of their lives. A radical shift is required in how products are designed by engineers. This process is sometimes called ‘eco-design’ or ‘green design’. For example, materials should be sourced from other ‘dead products’ rather than fresh sources. The designer should consider how those disposing of the product will be able to sell it on for another use, as a valuable commodity.
A final area where there is huge scope for engineering creativity is in water and sanitation, which is sometimes abbreviated to ‘watsan’. It was engineers who, in 19th century Victorian Britain, constructed the water supply and sewerage systems that enabled London to be significantly cleaner and less disease-ridden. The principles of good water supply and sanitation have been known since Roman times. Yet, many in the world still go without clean water, and there are large inequalities between water use from country to country. Innovative, cheap, appropriate solutions to give people access to clean water are in great need.
In summary, the situation on our planet is currently unsustainable. Human beings are ‘living on the capital rather than the interest’. A range of urgent changes is required if the effects of catastrophic climate change, over-use of resources and widespread pollution are to be avoided. Engineering has a key role to play in many areas, including energy, materials, waste, and water and sanitation.
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