Page 97 - Materials Chemistry, Second Edition

Life Cycle Assessment: Principles, Practice and Prospects
84

100%
Per cent contribution to total 70% Non-residential buildings
90%
80%

60%
Multi-unit residential
50%
Home improvement
40%
Separate houses
30%
20%
10%
0%
Photochemical oxidation
Global warming Eutrophication Carcinogens Land use Water use Solid waste Cumulative energy Minerals

Figure 7.4 Contribution to indicators by each construction type (DEWR 2007) (‘Global warming’
is interchangeable with greenhouse gas emissions).

Assuming new house size will decline slightly and multi-unit residential properties will
stabilise by 2055, total materials use by mass will grow by almost 40% due to growth in building
demand. As a consequence, greenhouse gas emissions will rise by 40% and water use by 63%.
Concrete use is expected to more than double over the next 50 years, with bricks making up a
decreasing share partly due to the shift to multi-unit residences and away from separate houses.
The remaining materials of significance are steel, softwood, plasterboard and mortar.
Modelling of the eight future scenarios showed that a combination of options, incorporat-
ing existing or currently forecast technology, has the potential to reduce greenhouse gas emis-
sions from materials use by 45% by 2055 from the unabated growth (business-as-usual)
scenario (i.e. to hold impacts at 2005 levels). Figure 7.5 illustrates the results for each scenario,

25 Unabated house demand reduction

Global warming potential (kt CO 2 eq.) 15 - Base case
20

- Increase shift to multi-unit
- Reduction in demolition rate
- Slow lowering in house size
- Increase persons per household
Fast lowering in house size
- Combined house demand reduction
10

5

1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055

Figure 7.5 Annual greenhouse impacts from building materials from 1985 to 2055 under different
building demand scenarios (kilotonnes of carbon dioxide equivalents) (DEWR 2007).

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