Negative emissions—Part 2: Costs, potentials and side effects

Summary

This systematic review, part 2 of a three-part assessment, synthesises peer-reviewed literature on seven negative emissions technologies (BECCS, afforestation/reforestation, DACCS, enhanced weathering, ocean fertilisation, biochar, and soil carbon sequestration) and presents evidence-based estimates of their sustainable global deployment potentials, costs, and side-effects by 2050. The authors conclude that while potentials range from 0.5–5 GtCO₂ yr⁻¹ across most technologies (up to 5 GtCO₂ yr⁻¹ for soil carbon sequestration and enhanced weathering), no single NET is likely to sustainably achieve the removal rates required for 1.5 °C climate scenarios. The findings highlight wide variation in cost-effectiveness, permanency, and trade-offs across technologies, informing policy and investment decisions.

UK applicability

The UK is a signatory to net-zero and climate targets requiring assessment of feasible emissions reduction pathways; this review's appraisal of soil carbon sequestration, afforestation, and BECCS potentials and costs is directly relevant to UK climate policy and land-use strategy. However, the global estimates require contextualisation for UK biophysical and socio-economic conditions, particularly the limited land availability and competing land uses in the UK.

Key measures

Global CO₂ removal potential (GtCO₂ yr⁻¹ by 2050), technology costs, permanency of carbon sequestration, environmental and socio-economic side-effects

Outcomes reported

The study systematically reviewed literature on seven negative emissions technologies (NETs) and provided quantitative estimates of their sustainable global potentials by 2050, costs, permanency, and side-effects. It assessed whether individual NETs could sustainably meet carbon uptake rates required for 1.5–2 °C climate pathways.

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