The feasibility of reaching gigatonne scale CO2 storage by mid-century

The Sixth Assessment Report by the Intergovernmental Panel on Climate Change projects subsurface carbon storage at rates of 1 - 30 GtCO(2) yr(-1) by 2050. These projections, however, overlook potential geological, geographical, and techno-economic limitations to growth. We evaluate the feasibility of scaling up CO2 storage using a geographically resolved growth model that considers constraints from both geology and scale-up rate. Our results suggest a maximum global storage rate of 16 GtCO(2) yr(-1) by 2050, but this is contingent on the United States contributing 60% of the total. These values contrast with projections in the Sixth Assessment Report that vastly overestimate the feasibility of deployment in China, Indonesia, and South Korea. A feasible benchmark for global CO2 storage projections, and consistent with current government technology roadmaps, suggests a global storage rate of 5-6 GtCO(2) yr(-1), with the United States contributing around 1 GtCO(2) yr(-1).