Negative emissions pose trade-offs among human health, planetary boundaries and mineral resources

We will need to deploy Negative Emissions Technologies or Practices (NETPs) at scale to achieve the Paris goals, yet their global environmental implications remain unclear. Here we conducted a harmonized prospective life cycle assessment of 27 NETPs systems to quantify the environmental impacts of meeting CO ₂ removal (CDR) targets between 2030 and 2050, using standard and absolute sustainability metrics complemented with resource requirement indicators. We found multiple trade-offs that may hinder the large-scale adoption of NETPs. Enhanced weathering and forestation could pose a risk to human health, while NETPs based on intensively managed plantations (biochar and Bioenergy with Carbon Capture and Storage) could exert substantial damage to human health, ecosystems, and multiple Earth-system processes. Moreover, the latter could sharply raise the global demand for certain nutrients essential for plant growth, potentially threatening food security. Direct Air Carbon Capture and Storage (DACCS) and ocean liming generate the least collateral damage, although DACCS could critically exacerbate the mining levels of certain mineral resources. The sustainable and safe operation of the CDR industry will imply balancing multiple risks and designing optimal NETPs portfolios tailored to region-specific constraints.