Accounting for spatial variability in life cycle cost-effectiveness assessments of environmental impact abatement measures
Authors: Pexas Georgios , Mackenzie Stephen G. , Wallace Michael , Kyriazakis Ilias 
Published: June 2021

Abstract
Purpose
The environmental and economic impacts of livestock production systems are typically assessed using global characterisation factors and data, even though several impact categories call for site-specific assessments. Here, we account for spatial variability by addressing potential interactions between geographic locality and the cost-effectiveness of farm investments that aim to reduce system environmental impact, using Danish pig production as a case-in-point.

Methods
An LCA-based, spatially explicit environmental abatement cost framework was developed to assess the cost-effectiveness of potential environmental abatement strategies. The framework was tested for Danish pig production in a “4 manure management × 4 geographic location” scenario analysis design. In addition to the baseline, the alternative manure management strategies were on-farm anaerobic digestion, slurry acidification and screw press slurry separation, implemented in an integrated pig farming system. The geographic locations differed in their proximity to Natura 2000 areas and in pig farming density. Eight different impact categories were assessed through an LCA using spatially explicit characterisation factors whenever possible, and annualised abatement potential was estimated for each manure management scenario and in each geographic location. We also estimated the financial performance for each scenario, through a discounted cash flow analysis at a whole-farm level.

Results and discussion
We observed significant interactions between geographic location and system environmental and economic performance under baseline conditions. Significant location effects were also observed for the cost-effectiveness of all manure management strategies tested. Anaerobic digestion was the only “win–win” strategy that increased farm profits while reducing system environmental impact in two of the geographic cases: when implemented in a region of high pig farming density located near Natura 2000 and when implemented in a region of high pig farming density located far from Natura 2000 areas. Slurry acidification and slurry separation achieved sizeable abatement potential for impacts on ecosystem quality but incurred large additional costs in all geographic case studies considered, particularly when arable land was limited near the pig farm.

Conclusions
Accounting for basic spatial characteristics within an environmental abatement cost framework had significant impact on the cost-effectiveness of on-farm investments for mitigation of system environmental impact. To the best of our knowledge, no studies to date have utilised such spatial characteristics within environmental abatement cost modelling of livestock farming systems. The presented framework has the potential to be further expanded using more detailed spatial, economic and geophysical data, which could ultimately improve decision-making regarding cost-effective investments that aim to improve the sustainability of livestock farming operations.