AGRICULTURAL REFERENCE SYSTEMS IN LIFE CYCLE ASSESSMENTS - Economics of Sustainable Energy in Agriculture - page 109

In this example the same area size is considered in every system.
However, since conventional farming methods tend to achieve higher
yields than organic farming, the 'surplus' area can be used e.g. for biofuels
- or for fallow. The comparison of the results shows that even when an
equal area size is considered and the same commodities are produced, the
results of the calculations may differ widely between the various systems,
depending on the production methods and the way in which surplus land is
utilised. Thus the examples presented here show once more how crucial it
is to define the question to be answered by the LCA very precisely, and
conversely, that the results must be discussed and interpreted only within
the context and the particular conditions and system boundaries relevant to
the individual case.
4. CONCLUSION AND OUTLOOK
The theoretical considerations as well as the examples presented above
indicate that the precise definition of an appropriate reference system is of
critical importance within agricultural life cycle analyses. The reference
system comprises firstly the reference area which defines the
environmental effects arising if the area in question was to be utilised
differently, and secondly it includes any indirect effects that arise from the
respective land use, for example additional transports or emissions due to
different production methods, as well as the effects of potential land use
changes elsewhere that result from the investigated production. As
discussed in Section 2 it must finally end with an area that does not
produce any economic commodity.
The examples shown here indicate that different agricultural
reference systems lead to different scenarios which can have a significant
impact on the results. In practice, the reference system is not 'chosen' or
'derived' but can be directly deduced from the question on which the LCA
is based, provided that this question is formulated precisely enough.
Therefore, it is an important aspect of any LCA to clearly define the
question to be answered through it. This is also crucial to the question of
how biofuels compare to conventional fossil fuels in environmental terms,
under the respective conditions relevant to the particular case.
ACKNOWLEDGEMENTS
The financial support of the Bundesministerium für Landwirtschaft, Ernährung und Forsten
(Ministry for agriculture, food and forestry) for the project on which this chapter is based is
gratefully acknowledged.