The planetary boundaries framework contains regional boundaries in addition to global boundaries. Geographically resolved methods to assess regional environmental impacts are therefore needed. Existing planetary boundaries-based life cycle assessment (PB-LCA) methods have limited geographical resolution or are not applicable to full product systems, due to high spatial requirements on inventory data. Here, we enable PB-LCA of full product systems across a comprehensive set of regional and global PB impact categories. We propose comparing environmental impacts of individual processes within a product system to assigned shares of regional or global safe operating space (SOS). This is followed by aggregation of process-level results so that accumulated exceedance of assigned SOS is derived across the entire life cycle. We then present a procedure for aggregating geographically resolved characterization factors (CFs) and SOS to country, continent and global levels, ensuring compatibility with typical life cycle inventory results. We then apply the new techniques to a model laundry case study. It involves 61 selected processes, two geographically resolved PB-LCA methods, related to impacts from freshwater use and nitrogen emissions, and a largely spatially generic PB-LCA method that covers a comprehensive set of impact categories. The calculation of accumulated exceedance of assigned SOS may help inform decisions about where in a life cycle to focus impact reduction efforts most urgently. The number of case study processes that exceed their assigned SOS differs when applying the geographically resolved methods, as opposed to the largely spatially generic method. Case study results differ greatly across PB-LCA impact categories, reaffirming the importance of covering a comprehensive set. Geographically resolved methods are needed for all regional impact categories and software support would be advantageous. Existing methods will require periodic updates to reflect ongoing advancements in PB science. Best practice approaches or a consensus for assigning regional SOS to processes are needed. Our study provides a step towards greater operability of geographically resolved PB-LCA methods by enabling application to a full product system within an assessment that covers a comprehensive set of impact categories. The case study application shows potential advantages of the process-level approach and points to the need for quantifying uncertainties in such assessments. Future studies should seek to explore the potential role of PB-LCA in decision support compared with conventional LCA.

中文翻译：

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将行星和区域边界应用于过程级别的生命周期评估：模型案例研究

行星边界框架除了包含全球边界外，还包含区域边界。因此，需要通过地理解析方法来评估区域环境影响。由于对清单数据的高空间要求，现有的基于行星边界的生命周期评估 (PB-LCA) 方法具有有限的地理分辨率或不适用于完整的产品系统。在这里，我们在一组全面的区域和全球 PB 影响类别中启用完整产品系统的 PB-LCA。我们建议将产品系统内各个流程的环境影响与区域或全球安全操作空间 (SOS) 的分配份额进行比较。然后汇总过程级结果，以便在整个生命周期中累计超出指定的 SOS。然后，我们提出了一个将地理解析特征因子 (CF) 和 SOS 聚合到国家、大陆和全球级别的程序，确保与典型生命周期清单结果的兼容性。然后，我们将新技术应用于模型洗衣案例研究。它涉及 61 个选定的过程，两个地理上解决的 PB-LCA 方法，与淡水使用和氮排放的影响有关，以及一个主要空间通用的 PB-LCA 方法，涵盖了一系列综合影响类别。指定 SOS 累计超标的计算可能有助于决定生命周期中最紧迫的减少影响工作的重点。应用地理解析方法时，超出其指定 SOS 的案例研究过程的数量会有所不同，这与大部分空间通用方法相反。不同 PB-LCA 影响类别的案例研究结果差异很大，重申了涵盖全面集合的重要性。所有区域影响类别都需要地理解析方法，软件支持将是有利的。现有方法将需要定期更新以反映 PB 科学的持续进步。需要将区域 SOS 分配给流程的最佳实践方法或共识。我们的研究通过在涵盖一系列综合影响类别的评估中应用到完整的产品系统，为提高地理解析 PB-LCA 方法的可操作性迈出了一步。案例研究应用程序显示了过程级方法的潜在优势，并指出需要量化此类评估中的不确定性。