Hahn Thomas, Morfeldt Johannes, Höglund Robert, Karlsson Mikael, Fetzer Ingo
Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
Physical Resource Theory, Department of Space, Earth and Environment, Chalmers University of Technology, Gothenburg, Sweden.
Nat Commun. 2024 Nov 9;15(1):9707. doi: 10.1038/s41467-024-54039-x.
Quantifying fair national shares of the remaining global carbon budget has proven challenging. Here, we propose an indicator-additional carbon accountability-that quantifies countries' responsibility for mitigation and CO removal in addition to achieving their own targets. Considering carbon debts since 1990 and future claims based on countries' emission pathways, the indicator uses an equal cumulative per capita emissions approach to allocate accountability for closing the mitigation gap among countries with a positive total excessive carbon claim. The carbon budget is exceeded by 576 Gigatonnes of fossil CO when limiting warming below 1.5 °C (50% probability). Additional carbon accountability is highest for the United States and China, and highest per capita for the United Arab Emirates and Russia. Assumptions on carbon debts strongly impact the results for most countries. The ability to pay for this accountability is challenging for Iran, Kazakhstan and several BRICS+ members, in contrast to the G7 members.
事实证明，量化各国在全球剩余碳预算中应公平承担的份额具有挑战性。在此，我们提出了一个指标——额外碳责任，该指标除了衡量各国实现自身目标的情况外，还量化了各国在减排和碳清除方面的责任。该指标考虑了自1990年以来的碳债务以及基于各国排放路径的未来需求，采用人均累计排放量相等的方法，在总过度碳需求为正的国家之间分配缩小减排差距的责任。当将升温限制在1.5°C以下（概率为50%）时，化石碳排放量超过碳预算5760亿吨。美国和中国的额外碳责任最高，阿拉伯联合酋长国和俄罗斯的人均额外碳责任最高。碳债务假设对大多数国家的结果有很大影响。与七国集团成员相比，伊朗、哈萨克斯坦和几个金砖国家加成员国难以承担这种责任。
