Advanced Resource Efficiency Centre, University of Sheffield, Sheffield S10 1FL, UK.
Management School, University of Sheffield, Sheffield S10 1FL, UK.
Nat Plants. 2017 Mar 1;3:17012. doi: 10.1038/nplants.2017.12.
Food production and consumption cause approximately one-third of total greenhouse gas emissions, and therefore delivering food security challenges not only the capacity of our agricultural system, but also its environmental sustainability. Knowing where and at what level environmental impacts occur within particular food supply chains is necessary if farmers, agri-food industries and consumers are to share responsibility to mitigate these impacts. Here we present an analysis of a complete supply chain for a staple of the global diet, a loaf of bread. We obtained primary data for all the processes involved in the farming, production and transport systems that lead to the manufacture of a particular brand of 800 g loaf. The data were analysed using an advanced life cycle assessment (LCA) tool, yielding metrics of environmental impact, including greenhouse gas emissions. We show that more than half of the environmental impact of producing the loaf of bread arises directly from wheat cultivation, with the use of ammonium nitrate fertilizer alone accounting for around 40%. These findings reveal the dependency of bread production on the unsustainable use of fertilizer and illustrate the detail needed if the actors in the supply chain are to assume shared responsibility for achieving sustainable food production.
粮食生产和消费导致了约三分之一的温室气体排放，因此，实现粮食安全不仅挑战了农业系统的生产能力，也对其环境可持续性提出了挑战。如果农民、农业食品行业和消费者要共同承担减轻这些影响的责任，就必须了解特定食品供应链中环境影响发生的地点和程度。在这里，我们分析了全球饮食主食之一——面包的完整供应链。我们获得了制造某一特定 800 克面包品牌所涉及的农业、生产和运输系统的所有流程的原始数据。使用先进的生命周期评估 (LCA) 工具对数据进行了分析，得出了包括温室气体排放在内的环境影响指标。结果表明，生产面包的环境影响有一半以上直接来自于小麦种植，仅使用硝酸铵肥料就约占 40%。这些发现揭示了面包生产对化肥不可持续使用的依赖，并说明了供应链中的各个环节如果要共同承担实现可持续粮食生产的责任，就需要详细了解情况。
