Consistent temporal accounting supports credible CDR use

Carbon dioxide removal (CDR) is increasingly used to support national targets and corporate net-zero commitments, yet the timing of atmospheric drawdown remains poorly represented in carbon accounting frameworks. Many CDR pathways exhibit temporal lags—either because drawdown occurs only after physical or counterfactual processes unfold, or because excess emissions are incurred before CDR begins. Using the FaIR climate model, we quantify the warming implications of four archetypal lag structures. Temporal lags consistently increase near-term warming relative to instantaneous removal and delay the point of atmospheric neutralization when used to offset fossil emissions. Under continuous global deployment in a low emissions scenario, lagged CDR increases peak global temperatures, and some lag types increase the likelihood of peak temperatures exceeding 2°C by up to 6% across 841 ensemble members. These effects arise even when cumulative removals equal cumulative emissions. We propose tractable approaches to addressing these temporal lags, enabling more credible climate claims and consistent treatment across CDR pathways.