Li Mingyu, Pelz Setu, Lamboll Robin, Wang Can, Rogelj Joeri
School of Environment, Tsinghua University, Beijing, China.
Centre for Environmental Policy, Imperial College London, London, UK.
Nat Commun. 2025 Jan 26;16(1):1043. doi: 10.1038/s41467-025-56397-6.
Equity is a cornerstone of global climate policy, yet differing perspectives mean that international agreement on how to allocate mitigation efforts remains elusive. A rich literature informs this question, but a gap remains in approaches that appropriately consider non-CO emissions and their warming contributions. In this study, we address this gap and define a global warming budget applicable to all anthropogenic greenhouse gases that is allocated to countries based on principles drawn from international treaties and environmental law. We find that by 2021 a range of 84 to 90 countries, including but not limited to all major developed countries, exhausted their budget share compatible with keeping warming to 1.5 °C (with 50% likelihood) under all allocation approaches considered in this study. A similar picture emerges for limiting warming to 2 °C (with 67% likelihood). A large group of countries will hence exceed their fair shares even if their pledges under the Paris Agreement represent their deepest possible emission reductions. Considerations of fairness should therefore start exploring aspects beyond domestic emissions reductions.
公平是全球气候政策的基石，但不同的观点意味着在如何分配减缓努力方面达成国际协议仍难以实现。丰富的文献探讨了这个问题，但在适当考虑非二氧化碳排放及其变暖贡献的方法方面仍存在差距。在本研究中，我们弥补了这一差距，定义了一个适用于所有人为温室气体的全球变暖预算，并根据国际条约和环境法的原则将其分配给各国。我们发现，到2021年，包括但不限于所有主要发达国家在内的84至90个国家，在本研究考虑的所有分配方法下，耗尽了其与将升温控制在1.5°C（可能性为50%）相符的预算份额。在将升温限制在2°C（可能性为67%）的情况下，也出现了类似情况。因此，即使一大群国家根据《巴黎协定》做出的承诺代表了它们可能实现的最大减排量，它们仍将超过其公平份额。因此，公平考量应开始探索国内减排以外的方面。
