The Need for Sustainability in The Built Environment
The industrial revolution provided the bulk of the construction industry with the materials to construct buildings in a standardised format, invariably, from the 1950’s onwards, this included concrete footings and block-work, with an outer brickwork skin.
In the 1970’s, the honest and apparent use of concrete was re-enforced to provide an economical material for high-rise flats, and it was often used in formwork to provide curved and interesting structure.
Originating from Roman influence, the cement used in construction processes has traditionally provided a solid and reliable glue for almost all buildings, although in rural areas, many local people continued to use more ecologically robust materials, including cob in the UK, especially Norfolk and Suffolk where lime facing work was decorated with pargeting.
Manufactured cement emits 1 ton of CO2 output for every 1 ton of cement produced. Half of this CO2 emission comes from the energy used to calcine limestone, the other half is from the chemical reaction of the limestone. (U.S. Environmental Protection Agency 2009, Resource Conservation Challenge Workshop Washington DC, March 25th, 2009)
The CO2 emissions associated with clay brick manufacture equate to 0.000225 tonnes of CO2 per square metre of brickwork, 2007 data. (Sustainable Strategy for the Brick Industry.)
In 2007, according to National Statistics, the recorded figure of £490,769,000 was attributed to brick sales in the UK.
At an average purchase price equating to £200 per 1000 bricks, and £16.70 per sq metre, this equates to a nominal 6,612 tonnes of CO2 emitted through brick manufacture in the UK in 2007.
A stark contrast to the amount of CO2 produced through cement manufacture globally for the same year, 2690 million tonnes – www.researchandmarkets.com/reports/651928/the_cement_industry_in_europe_and_the_middle.htm
The manufacture of concrete includes cement, sand and gravel. Obviously for every ton of concrete, apart from the CO2 emissions involved in the manufacture of cementacious primer, sand and gravel will have been quarried, adding to the over-demand of this planet’s resources, and with excavation machinery and transportation of the conglomerates, this considerably adds to global strain.
While concrete remains the second most used material globally, there will remain abundant CO2 emissions through the manufacture of cement, continuing the speed of climate change.
According to Jeremy Faludi, 18th November 2004 “Concrete a ‘Burning’ Issue – http://www.worldchanging.com/archives/001610.html - concrete creates 7-10% of CO2 emissions worldwide.
Consumer Demand Exceeds 1.2 Worlds Resources;
(A REAP Project: Stockholm Environment Institute, Rachel Birch, Tommy Wiedmann and John Barrett, January 2006), and as detailed on Breckland Council Development Control Department.
According to this SEI report, humanity’s ecological footprint exceeds Earth’s biological capacity by a factor of at least 20% above Earth’s natural resource levels.
This report is based on demand levels from 1961, when demand stood at only 50% global capacity, rising consistently to the 1.2 world level in 2001.
Some people estimate that the level as it stands in 2009 actually exceeds 1.6 world’s resources, according to one report, although it has not been possible to substantiate this level at the time of preparation of this report.
Based upon SEI research, the UK demand is 65% higher than the global ecological budget. The USA demand exceeds UK levels.
There is a direct correlation between a countries wealth and the over-demand of our planet’s resources. The UK’s Ecological Footprint at the time of this report, stood at 5.4 global hectares per person, whereas Indian and Ethiopian demand levels stood at under 1 global hectare per person.
The SEI study shows demand levels as:
Food 20%
Household Energy 16%
Manufactured Consumables 12%
Transport 15%
There is no detail for the construction sector, but as detailed previously, cement alone accounts for an equal tonnage in CO2 emissions for every ton manufactured.
Considering these levels of over demand on global resources is crucial when forming sustainable community living projects.
A global ecological overshoot exceeding the Earth’s bio-capacity by 20% in 2001, results in the harvesting of trees and fish, before they have the opportunity of replenishing. This ecological overshoot is also reflected in the levels of CO2 being emitted faster than it can be absorbed by eco-systems.
It is obvious that reducing CO2 emissions alone, will not redress the current imbalance in over-demand, nor help to balance the status quo.
