Sharing emissions and removals for meeting the Paris Agreement through a distributive and corrective justice lens

Carbon dioxide removal (CDR) is critical for achieving net-zero and net-negative CO2 emissions that can halt and potentially reverse global warming, respectively. However, reliable CDR is still costly and comes with considerable technological and ecological uncertainties. Considering global CDR employment from a fairness perspective serves as a starting point to inform national actions and international cooperation, as well as to provide guidance for the formulation and evaluation of nationally determined contributions (NDCs) and long-term low-emission development strategies (LT-LEDS) for which countries need to indicate how they represent a fair and ambitious contribution. Despite the centrality of equity, no integrated framework exists to equitably allocate responsibilities for CDR and residual emissions among countries.

Here, we present a justice-based framework that separates out ethical considerations for equitably allocating gross emissions and gross CDR, addressing how these contributions shift before and after reaching global net-zero CO2 emissions. We distinguish between distributive justice, which refers to ethical principles guiding the fair allocation of scarce resources and rights from a forward-looking perspective, and corrective justice, which applies when losses and damages arising from the excessive use of environmental commons must be addressed. Building on distributive and corrective justice theories, the framework distinguishes between CDR delivered as a common good to reach a collective global climate outcome, and CDR that is used to pay off carbon debts due to emissions overconsumption. We apply the framework to 1.5 °C-consistent scenarios and national projections, covering 176 countries and focusing on durable, engineered CDR options.

Our results reveal substantial divergences between justice-based allocations and technically optimized IAM pathways. High-income regions are systematically assigned larger corrective CDR obligations, while in the Global South, technically modeled pathways generally project fewer residual emissions and larger potential for CDR deployment compared to the justice-based allocation benchmarks, principally in Africa, Southern Asia, and Latin America & the Caribbean. A limited amount of countries provide quantitative information regarding residual emissions and CDR in their LT-LEDS, and even fewer meet their equitable quota. Out of 26 residual emission pledge estimations, only Fiji and Ethiopia stay within their equitable allocation. Out of 38 CDR pledge estimations, 19 countries meet or exceed their equitable CDR allocation, showing a tendency to overly rely on CDR deployment in major countries.

In this work, we offer a new perspective for how nations with substantial historical responsibilities and emerging economies with increasing capacities can collaborate and equitably share the CDR burden, enhancing both international cooperation and national-level climate action.