Diverse carbon dioxide removal approaches could reduce impacts on the energy-water-land system

Carbon dioxide removal (CDR) is a critical tool in all plans to limit warming to below 1.5 degrees C, but only a few CDR pathways have been incorporated into integrated assessment models that international climate policy deliberations rely on. A more diverse set of CDR approaches could have important benefits and costs for energy-water-land systems. Here we use an integrated assessment model to assess a complete suite of CDR approaches including bioenergy with carbon capture and storage, afforestation, direct air capture with carbon storage, enhanced weathering, biochar and direct ocean capture with carbon storage. CDR provided by each approach spans three orders of magnitude, with deployment and associated impacts varying between regions. Total removals reach approximately 10 GtCO(2) yr(-1) globally, largely to offset residual CO2 and non-CO2 emissions, which remain costly to avoid even under scenarios specifically designed to reduce them. Carbon dioxide removal will be essential to reaching ambitious climate goals by offsetting hard-to-abate emissions and drawing down legacy CO2. A diverse portfolio of CO2 removal strategies, rather than any single approach, could achieve gigatonne-scale removals while limiting risks to the water-energy-land system.