Negative emission technologies: a way forward?

Abstract

Negative Emission Technologies (NETs) can play a pivotal role in mitigating climate change by removing CO₂ from the atmosphere, complementing emission reduction efforts especially as 1.5 °C Paris Agreement targets are exceeded and historical emissions removals are required. This review systematically evaluates the current landscape, technical performance, and scalability of key NETs, including Bioenergy with Carbon Capture and Storage (BECCS), Direct Air Carbon Capture and Storage (DACCS), afforestation, soil carbon sequestration and biochar, enhanced weathering, and ocean-based methods. Technological advancements required are analyzed to highlight and enhance the efficiency, scalability, resource requirements (land, water, and minerals), and economic viability of these solutions. The interplay between NETs and existing emissions reduction strategies is critically examined, emphasizing the need for synergies that maximize overall climate benefits while minimizing resource competition. Comparative analyses highlight differences in technological readiness, energy use, and environmental impacts, offering insights into the practical and theoretical limits of CO₂ sequestration for each approach. The review also explores energy balances, cost structures, and life-cycle assessments (LCA), identifying bottlenecks in deployment and potential areas for innovation to enhance efficiency and reduce costs. Additionally, we evaluate the current policy frameworks that support NET development, identifying key challenges in both governance and measurement/reporting/verification (MRV) that must be addressed to facilitate widespread deployment. The review underscores the necessity for robust international cooperation and financing mechanisms tailored to NETs, particularly for capacity building in developing regions. As we pursue a net-zero future, addressing the research gaps and promoting effective integration of NETs into comprehensive climate strategies will be crucial for mitigating the long-term impacts of anthropogenic CO₂ emissions.