https://www.sciencedirect.com/science/article/pii/S0959378026000038
Authors: Julia Danzer, Gottfried Kirchengast
26 February 2026
Highlights
•Recent studies show mounting evidence that the sustainable CDR budget is limited.
•Simple new model for studying fairness in emission and removal shares of countries.
•Key principles are fair-sharing and contraction-and-convergence budget allocations.
•Unfair policies of countries and overuse critically challenge the limited CDR budget.
•Fairness in removal budgets needs similar attention as remaining emission budgets.
Abstract
Towards achieving the Paris goal of limiting global warming to well below 2°C with an effort to reach 1.5°C, countries not only need to drastically reduce their emissions but also to partially deploy carbon dioxide removal (CDR). CDR from the atmosphere can be achieved by various methods, ranging from nature-based solutions to technical options. We started with a survey of recent studies and found mounting evidence that CDR use needs great caution, since there exist strong biophysical and socio-economic constraints on scaling it up; and emission and removal fluxes are not equivalent in terms of climate outcomes. Also, carbon storage needs to be safe and durable, implying further challenges. We hence find it essential, yet under-researched currently, to explicitly study fairness also in the allocation of a limited global carbon removal budget if countries are to pursue the transition to net-zero and beyond in a fair way. We introduce a simple emissions and removal model (“SERM”) for this purpose and use it for an initial analysis exploring different fairness policies in a conceptual toybox world (“Austro-World”) with four stylized countries pursuing pathways towards net-zero. The policies range from equal-per-capita fair-sharing and grandfathering by per-capita-convergence to including fairness-perturbing country-level removal policies and unrealistic CDR budget sizes. We find substantial (un)fairness implications for CDR scale-up towards net-zero and long-term use beyond. This unveils that distributive justice across countries should be taken into account as seriously for the limited carbon removal budget as it is for the remaining carbon emission budget.
Source: ScienceDirect