Consistency check for life cycle assessments

Purpose: This paper seeks to provide a detailed procedural description for performing a consistency check for LCA as required by the ISO 14044 standard. Methods: Consistency is defined as freedom from logical contradictions. The requirements of ISO 14044 are reviewed, and detailed guidance is provided for these and other related consistency issues. Results and discussion: The procedural guidance reflects the iterative nature of the phases of LCA. Some inconsistencies can be of a more fundamental nature that does not allow a single consistent solution. Instead, more than one separately consistent solution can then be found and applied as separate “scenarios” presented to the decision maker with appropriate explanation of the fundamental differences of the scenarios, and their respective strengths and weaknesses for the decision context. Conclusions: Revisiting and correcting inconsistencies can avoid most consistency problems. However, lack of resources may prohibit such adjustments, and the inconsistencies and their implications for the conclusions may then simply be stated and the conclusions modified accordingly.