UCD Biosystem Engineering, School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Ireland.
J Environ Manage. 2011 Mar;92(3):372-9. doi: 10.1016/j.jenvman.2010.10.025. Epub 2010 Nov 5.
Life cycle assessment (LCA) is a method regulated by ISO that conveys the environmental impact of products. LCA studies of the same product should be comparable to benefit environmental policy making. LCA of milk production has evaluated environmental issues such as greenhouse gas emissions, resource utilisation and land use change. Thirteen LCA studies of European milk production were analysed for comparability, and direct comparison was difficult due to technical issues, arbitrary choices and inconsistent assumptions. The strengths and weaknesses of LCA for evaluating an agricultural system are identified and improvements for comparability of future studies are also considered. Future LCA of milk production should ensure that: (1) the production system is appropriately characterized according to the goal of study; (2) a clear description of the system boundary and allocation procedures is provided according to ISO standards; (3) a common functional unit, probably Energy Corrected Milk, should be used or assumed fat and protein content presented to enable comparisons; (4) where appropriate, site-specific emission factors and characterization factors should be used in environmental hotspots (e.g. manure management, spreading of synthetic fertilizer, production of purchased feed), and phosphorous loss should be better addressed; (5) a range of impact categories including climate change, energy use, land use, acidification and eutrophication should be used to assess pollution swapping, all of which are subject to national or regional directives; perhaps in the future biodiversity should also be included; and (6) the sensitivity to choices of methods and uncertainty of final results should be evaluated.
生命周期评估（LCA）是一种受 ISO 监管的方法，用于传达产品的环境影响。对于同一产品的 LCA 研究应具有可比性，以有益于环境政策制定。牛奶生产的 LCA 研究已经评估了温室气体排放、资源利用和土地利用变化等环境问题。对 13 项欧洲牛奶生产的 LCA 研究进行了可比性分析，但由于技术问题、任意选择和不一致的假设，直接比较较为困难。确定了 LCA 评估农业系统的优缺点，并考虑了提高未来研究可比性的改进措施。未来的牛奶生产 LCA 应确保：（1）根据研究目标适当描述生产系统；（2）根据 ISO 标准提供明确的系统边界和分配程序说明；（3）使用共同的功能单位，可能是能量校正奶，或假设脂肪和蛋白质含量以进行比较；（4）在适当的情况下，应在环境热点（如粪肥管理、合成肥料的施用、购买饲料的生产）中使用特定地点的排放因子和特征化因子，并更好地解决磷损失问题；（5）使用一系列包括气候变化、能源使用、土地利用、酸化和富营养化在内的影响类别来评估污染交换，所有这些都受到国家或地区指令的约束；或许未来还应包括生物多样性；（6）应评估方法选择的敏感性和最终结果的不确定性。
