Researchers caution about reliance on CO₂ removal

Nearly all models in the latest report from the United Nations Intergovernmental Panel on Climate Change (IPCC) rely to some extent on carbon dioxide removal (CDR) to keep warming below 2 °C and reach net-zero carbon emissions. But a new study warns that heavy reliance on large-scale CDR projects would have a huge impact on both people and the environment ( Science 2024, DOI: 10.1126 /science.adj6171 ). For example, the IPCC estimates that producing bioenergy with carbon capture and storage (BECCS) could remove up to 11.3 billion metric tons (t) of CO 2 per year. Afforestation and reforestation, which rely on newly planted trees to sequester CO 2 , could remove an additional 10.0 billion t of the greenhouse gas annually. However, to achieve the full mitigation potential of these methods, countries would have to collectively convert 29 million km 2 of land to bioenergy crops or trees—approximately three times