Best practices for consistent and reliable life cycle assessments of urban agriculture.

There is increasing interest in evaluating the environmental performance of urban agriculture (UA), primarily using life cycle assessment (LCA). However, LCA has been applied to UA inconsistently, making it difficult to confidently compare or draw conclusions from existing studies. This article outlines the key challenges of applying LCA to UA and recommends concrete steps to bring consistency and comprehensiveness to the topic. The research questions that LCA can address are framed before providing practical recommendations for performing LCAs of UA, considering several of its unique aspects that require special attention by practitioners. These include crop diversity, data availability, modeling compost, soil carbon sequestration, producing growing media, distribution of crops, and variability and uncertainty. Next, the article proposes future research areas that will benefit LCA generally and its application to UA, such as framing UA as urban green infrastructure, evaluating at the city scale, accounting for ecosystem services, and including social dimensions of UA. By following these recommendations, future LCAs of UA can be more consistent, comparable, and holistic, and will help build knowledge and inform policy-making and practices around UA. [Display omitted] • Life cycle assessment can address key societal issues relevant to urban agriculture. • Its application to urban agriculture raises multiple and unique challenges. • Handling of composts, crop distribution and growing media create large uncertainties. • Practical recommendations were derived to improve the reliability of LCAs. • Accounting for ecosystem services and social dimensions should be prioritized. [ABSTRACT FROM AUTHOR]