Comment on “Soil carbon sequestration in global working lands as a gateway for negative emission technologies”

Almaraz et al. (2023) use a modelling approach to estimate the impact of six land management practices on soil carbon sequestration (SCS). They consider all practices to be additive and to “offer an immediate negative emission technology (NET) for deployment” as opposed to those less practically or economically feasible in the short-term. Their approach is helpfully transparent in some respects. For example (a) stressing the importance of SCS being coupled to deep emission reductions; (b) only considering areas not already using SCS practices as contributing to climate mitigation; (c) clearly stating that they ignore socioeconomic barriers, focusing on technical potential. Nonetheless, we contend that the values presented by Almaraz et al. (2023) are considerable over-estimates. This is due to methodological inaccuracies and overly optimistic assumptions.