Does irrigation data matter in life cycle assessments?

Sammanfattning: Biofuels are seen as a key substitute for fossil fuels and an essential tool for mitigating climate change. A sensitivity analysis was conducted on the AB-LCA (agent-based life cycle assessment) made by Raül López i Losada and his research team. Their AB-LCA assesses the environmental performance of a subsidy that generates an allocation of the arable land in Götalands Södra Slättbygder (GSS) that dedicate 25 percent of the arable land for grass leys later used for biofuel production. Irrigation data in the life cycle setup was identified as a sensitive input of interest due to its high variability. New, alternative irrigation data was collected from the Food and Agricultural Organization of the United Nations (FAO) and inserted in the life cycle system setup. A new impact result was generated with a life cycle assessment modeling software with the endpoint impact assessment methods ReCiPe 2016 and Impact World+. The collected irrigation data from FAO was on average 77 percent lower compared to the original data used in the AB-LCA which highlighted the importance of a sensitivity analysis like this. The substitution of irrigation data in the LCA software gave an average reduction in total impacts of 1,87 percent for human health and 2,33 percent for ecosystems, favoring the life cycle scenario where 25 percent of the arable land in GSS was covered by grass leys. The founding increased the environmental benefits of introducing grass ley rotations in GSS. This study showed that irrigation data matters for the AB-LCA impact results. The sensitivity analysis came to the same conclusion as the original AB-LCA which confirms that there are environmental benefits associated with dedicating 25 percent of the arable land in GSS to grass leys.