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Life-Cycle
Assessment
By Adrian Hill, NSW
Community Lead Advisory Service.
This article is based on an article called
"Life Cycle Assessment - What it is and How to do it" by the United Nations
Environment Programme, with thanks to Shenu Chanmagan.
Life cycle assessment (LCA) is a decision support
tool supplying information on the environmental effects of products. It furnishes
information on the environmental effects of all the stages of a product’s life cycle.
This information can be used by governments and by companies as well as by NGOs and
individual consumers when making decisions related to products.
Eco-labelling, product and
process improvements, and purchasing decisions, for example, can be supported by life
cycle assessment.
Today, knowledge of how to carry out an LCA is
improving rapidly. The value of the technique is being increasingly recognised and it is
now being used for strategic decision making and for designing environmental policies.
Because LCA integrates all the environmental
problems produced during the entire life cycle of a product or function, LCA can be used
to prevent three common forms of problem shifting:
- problem shifting from one stage of the life cycle to
another:
- problem shifting from one sort of problem to another:
and
- problem shifting from one location to another.
An LCA is an iterative process, in that the
assessment is repeated several times, each time in more detail. First, a superficial
analysis is made using approximate data; this results in a ‘quick-and-dirty’
assessment. Although such an analysis is sometimes all that is required, more often this
first assessment is used to highlight the points on which to focus to obtain an improved
assessment.
It is therefore important to know what level of
sophistication should be associated with a certain type of application. In product design,
for instance, results must be correct on average, that is most of the time; in
eco-labelling, they must almost always be correct.
Another application of LCA is to compare product
alternatives. In order to do this a suitable comparison criterion is needed and the most
basic criterion is the function that the product is to fulfil.
It would be nonsensical to compare a disposable
paper cup with a china cup, given that the life span of the two differs by a factor of at
least 100. Instead, the function of the two alternatives, such as drinking one cup of
coffee, could be compared. The function to be compared is referred to as the functional
unit.
Problems caused by LCA
Three of the major problems in using LCA have to do
with time:
- LCAs can take so long to perform that they delay
action,
- an LCA made one year may contradict the results of an
LCA made another year; and
- an LCA may hinder technological improvements which
later turn out to be environmental improvements as well.
The current complexity of LCA means that a long and
careful study must be made before a public LCA can be produced, especially since
stakeholders with opposed views will, if they can, justify their views by criticising the
way an LCA is made. This is not a characteristic of LCA in particular but applies to all
techniques of environmental analysis.
Although LCA often stimulates the development of
cleaner products, companies can also claim that, since an LCA shows that ‘product A
is best’ or an ecolabel has been awarded for a product, further innovation is not
needed. One solution to this problem is to restrict the validity of an
ecolabel, say to a
three-year period. Consideration can also be given to extending the principle of an expiry
date to other LCA applications
Framework
In response to the need for a unified framework for
LCA, the following framework has been developed by the United Nations Environment
Programme, based on one developed by SETAC (Society of Environmental Toxicology and
Chemistry):-
Goal definition and scope
The product(s) to be assessed are defined, a
functional basis for comparison is chosen and the required level of detail is defined.
2. Inventory analysis
The energy and raw materials used, and emissions to
the atmosphere, water and land are quantified for each process and then combined in the
process flow chart.
3. Impact assessment
The effects of the resource use and emissions
generated are grouped and quantified into a limited number of impact categories which may
then be weighted for importance.
4. Improvement assessment
The results are reported in the most informative way
possible and the need and opportunities to reduce the impact of the
product(s) on the
environment are systematically evaluated.
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