Environmental Sustainability & Construction

Environmental sustainability means that we are living within the regenerative capacity of our natural environment. Translating this to the built environment, it means drastically reducing the huge demands by the built environment on the natural environment while still maintaining all the attributes defining built quality, such as structural and aesthetic integrity.

Established in Week One was the notion that the global construction sector is very resource intensive, but lets refresh our memory of how significant this is in terms of the impact on the natural environment. Buildings consume 45-50% of total global energy, 50% of total global drinkable water, 60% of global bulk of raw materials, and 60% of timber products of which 90% of this is hardwood (has a longer gestation period to make it difficult to regenerate itself). In addition, buildings account for 50% of rainforest destruction, and 80% of forfeited global agricultural land.

Apart from these direct impacts, the construction industry also accounts for a disproportionate share of global pollution; about 23% of total air pollution in cities and 50% of greenhouse gas emissions. In a similar vein, the construction sector is responsible for 50% of global landfill wastes. This is particularly the case when all phases of built assets are included.

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The statistics above explain the assertion that 75% of all known factors responsible for global environmental degradation are traceable in one form or another to the built environment.

The construction industry is also an intense consumer of global natural resources and energy, particularly at the processing stage of construction materials, the majority of which are very resource and energy intensive. These include:

zinc; tin; iron ore; aluminium; lead; cement; tiles; bricks; steel; glass; paint

As the image below indicates, these materials embody huge energy resources, which occur during the process of conversion from raw materials to manufactured construction products. Concrete, steel, plastic, masonry and ceramics are particularly energy intensive.

(Click to expand) Source: CSIRO

Apart from the large amount of energy embodied in these products, massive environmental pollution occurs during processing where toxic gases and effluents are discharged into the environment. In turn, this pollution has harmful effects on aquatic and marine life, as well as contributing to atmospheric pollution. Some of the ‘greenhouse gases’ produced at the material processing stage include carbon dioxide (CO2); sulphur dioxide (SO2); nitrogen dioxide (NO2), and methane (CH4). These ‘greenhouse’ gases are heavily involved in the incidence of ‘global warming’, particularly CO2, which accounts for more that 50% of ‘greenhouse’ gases.

Do these figures surprise you? Before this course, what sector did you think was the most polluting?