Enhanced rock weathering (ERW) is a carbon dioxide removal (CDR) strategy that stores atmospheric CO 2 permanently in carbonates. Recent ERW literature has highlighted potential co-benefits from cropland ERW application, including reduced fertilizer requirements and soil N 2 O emissions. However, contributions of co-benefits to life cycle environmental impacts remain poorly understood, and methodologies for integrating them into environmental and cost assessments are lacking. We address these research gaps by integrating co-benefits into a coupled life cycle assessment and techno-economic analysis to quantify environmental impacts and costs of ERW with and without co-benefits. We assess both waste and virgin rock sourcing and transportation pathways in the United States. Our results show that cradle-to-farm-gate greenhouse gas (GHG) emissions of ERW, with long-range transport allowing nationwide deployment, range from 44 to 371 kg CO 2 eq/t CO 2 eq removal, and costs vary between US123 and US926/net t CO 2 eq removal, depending on rock type, sourcing, and transport mix. Fertilizer and N 2 O co-benefits can reduce GHG emissions of ERW deployment by 10. 4–55. 7%, costs by 3. 2–7. 6%, and other environmental impacts by 1–147%. The contributions of co-benefits are region-dependent, demonstrated by our spatial analysis of croplands across the United States. Our framework presents methodological advancement for CDR assessments and supports future deployment of ERW.
Kroeger et al. (Fri,) studied this question.