Contribution of LCA to decision making: A scenario analysis in territorial agricultural production systems
Résumé
Territorial Life Cycle Assessment (TLCA) appears a promising method to support informed decision making of local actors in territorial agricultural production systems (TAPS), by assessing environmental impacts of agricultural activities and potential strategies. The objectives of this study were to i) adapt TLCA methodology to integrated environmental assessment of TAPS and ii) evaluate TLCA’s contribution to supporting informed decision making by assessing scenarios of change in TAPS. A TLCA of the agricultural sector was performed for a territory in the Aube department in France, including main crops and animal production types from raw material extraction to the first stage of processing. Exchanges of agricultural products and by-products among agricultural subsectors were considered by allocating impacts, which prevented double-counting them. Two contrasting scenarios were assessed with TLCA – development of on-farm biogas production and reintroduction of sheep grazing – and compared to the current situation. Results were expressed per unit area (ha), per unit biomass produced (kg) and per percentage contribution to total impacts of the territory before and after processing (at and beyond the farm gate, respectively). The main contributors (cereal and oilseed crops) did not have the highest impact at the farm scale (per ha and per kg), which highlights that contribution to total impacts of the territory is a relevant addition to the impacts per functional unit. Consideration of exchanges showed that TLCA can be used to assess effects of material interactions (biomass flows) between sectors. Scenario results showed no significant differences in impacts, except for higher water resource depletion for the biogas scenario, because most differences between scenarios were smaller than uncertainties in the input data. Other challenges were identified, such as the need to evaluate consequences of changes beyond the territory gate when performing TLCA of scenarios or the utility of characterizing the network of biomass flows in more detail. In conclusion, the methodological framework that was developed successfully identified environmental hotspots and reflected environmental impacts of material interactions between actors. Finally, it can estimate environmental impacts of future strategies, as long as uncertainty is reduced; thus, it shows potential as a decision-support tool.
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