Beyond kg and ha - Functional Units for Multifunctional Agricultural Systems


Agricultural systems are inherently multifunctional. On the one hand, they simultaneously produce various agricultural goods (food, feed, fuel, fiber, etc.). On the other hand, agriculture is supposed to fulfill a range of societal functions beyond mere production, including preservation of soil fertility and maintenance of valued cultural landscapes. Not least, agriculture functions as a source of income for farmers and agricultural workers. This makes function and functional unit (FU) definition challenging. As a reference value for the life cycle impact assessment, it has a crucial impact on the results. We thus propose a set of criteria for assessing the suitability of FUs for attributional agriculture LCAs, depending on intended use (e. g. operational or policy decision support, food labeling, etc.). In LCA literature, usually production-related FUs (kg, kcal, ..) or area-related FUs (ha, ..) can be found. Both approaches have some shortcomings: Production-focused FUs usually encourage intensification, which might lead to higher local emissions as well as rebound effects. Furthermore, arbitrary divisions into main product and by-product, as well as sophisticated attribution methods, are often necessary. Area-focussed FUs on the other hand encourage extensification to the absurd, completely ignoring production (stopping farming altogether and thus producing nothing would always win any area-based comparison). Both traditional FUs fail to actually account for landscape conservation services and neglect the perspective of farmers. Harsh critique to both approaches can be found in scientific as well as political literature, since it touches the core of the land sparing – land sharing controversy. The thus damaged credibility among stakeholders may impair effectiveness of LCAs in agricultural decision support altogether. As a potential solution to this challenge, we explore several types of monetary FUs. Monetary FUs have been suggested for systems with obviously multi-functional designs, e. g. for agrivoltaics to combine electricity and agricultural goods into one product metric. However, this approach can have a number of further advantages: Monetary revenue is an important function in itself for key stakeholders like farm managers. In addition to that, monetary FUs could integrate neglected functions, such as landscape conservation services (e. g. by evaluating landscape attractiveness for tourism). Two metrics for monetary FU considered in this work are “gross margin” (perspective of producer side) and “value of produced agricultural goods and services” (perspective of consumer side). All in all, taking multifunctionality into account is a key for LCAs to be accepted across multiple stakeholder groups. While combining all the various functions into one metric can be challenging, monetary functional units may be an interesting alternative to product- and area-based ones.