“A reckless gamble” – new research finds states are over-relying on CDR in climate targets

“Over-reliance on CDR is a reckless gamble,” says Dr Rupert Stuart-Smith, Senior Research Fellow in Climate Science and the Law, at the Oxford Sustainable Law Programme and Smith School of Enterprise and the Environment. “We find that states are overwhelmingly intransparent and ambiguous about how they plan to meet their climate targets.” 

Inadequate near-term emission reductions in states’ climate targets are common, and create substantial long-term dependence on CO₂ removal to eliminate temperature overshoot, adds Dr Stuart-Smith. 

The authors warn this approach could jeopardise the Paris Agreement’s long-term temperature goals while increasing the risks of more severe climate change impacts, including the crossing of further planetary tipping points, entailing “irreversible consequences for human and natural systems.”

The study assessed climate strategies across 71 states, analysing emissions targets, carbon removal plans, and legal frameworks, and cross-referenced findings with leading climate data sources to highlight inconsistencies and risks in national net-zero pathways. Many rely heavily on both conventional and novel CDR technologies – including removals carried out in other countries – to offset emissions, rather than cutting them directly. The risks are especially acute when countries depend on international carbon trading or removals outside their borders, often without clearly quantifying this reliance. 

The authors also found some states are conflating CDR with natural carbon sinks like forests, which cannot be considered permanent and could lead to further reliance on CDR in the future. 

“CDR technologies have a crucial role to play in mitigating climate change, but they must not become a substitute for real emissions cuts,” says Dr Stuart-Smith. “To stay on track for net zero, countries must prioritise pathways that minimise overshoot and not postpone climate action in the hope that temperatures can subsequently be reduced by removing vast quantities of carbon from the atmosphere.”

CDR serves two main purposes in climate policy: offsetting CO2 emissions at the time they are produced and progress towards reaching net zero, and recapturing emissions produced in excess of a carbon budget. The extent to which offsetting is relied on affects how fast gross emissions must fall to achieve net emissions targets; reliance on CO2 removal for recapturing excess emissions will create overshoot and allows for weaker emission-reduction targets in the near term. As a consequence, IPCC emissions pathways in its Sixth Assessment Report indicate cuts in greenhouse gas emissions of 34-60% between 2019 and 2030, a key source of policy uncertainty. 

Previous research by the authors found that states that over-rely on CDR could find themselves out of alignment with international law. “Legal analysis, in conjunction with the risks associated with CDR-dependent targets assessed here could clarify states’ mitigation obligations under international law and facilitate progression past a risk-blind and indiscriminate use of scientific pathways in assessing states’ targets,” says co-author Dr Thom Wetzer, Associate Professor of Law and Finance and Director of the Oxford Sustainable Law Programme. 

The authors call for greater scrutiny of national climate plans and stronger international standards to ensure transparency and accountability in the use of CDR. They state: "High CDR reliance would exceed sustainable deployment limits and, potentially, planetary boundaries, deepen biodiversity loss and entail irreversible consequences for human and natural systems… mitigation pathways that minimize CDR should be prioritised in updated NDCs and climate strategies, which should also disclose the uncertainties and risks of incomplete CDR delivery.”