This article argues that an improved legal methodology is needed to ensure that states’ greenhouse gas emissions mitigation obligations are specified in line with best available science and the equity principle. In this vein, the article explores the extent to which the ‘meta-equity assessment’ of states’ emissions by the Climate Action Tracker (CAT) can contribute to this aim. The article finds that the CAT's PRIMAP Equity tool, embedded in the Potsdam Real-time Integrated Model for the probabilistic Assessment of emission Paths, offers the best available approach to distributing a global carbon budget among states in line with equity criteria recognized by the Intergovernmental Panel on Climate Change. The emissions data and global pathways used in the PRIMAP Equity tool can be updated. The major challenge ahead lies in understanding which of the emissions and temperature pathways can be applied in the legal context, and how.

本文认为，需要一种改进的法律方法来确保各州的温室气体减排义务是根据最佳可用科学和公平原则来规定的。本着这种精神，本文探讨了气候行动追踪系统 (CAT) 对各州排放量的“元股权评估”在多大程度上有助于实现这一目标。文章发现，CAT 的 PRIMAP Equity 工具嵌入了用于排放路径概率评估的波茨坦实时集成模型，提供了根据政府间小组认可的公平标准在各州之间分配全球碳预算的最佳可用方法关于气候变化。可以更新 PRIMAP Equity 工具中使用的排放数据和全球路径。