Phasing out the blast furnace to meet global climate targets

Iron and steel production is responsible for 7% of global greenhouse gas emissions. Earlier literature finds that the long economic life of steel production equipment impedes decarbonization in line with climate targets. Here, we estimate the cumulative emissions from existing primary steel production equipment if operated as historically observed, based on furnace-level data of historical operating patterns. We find that the emissions commitment of current primary steel equipment is significantly smaller (21 Gt CO₂eq) than previously suggested (52–65 Gt CO₂eq). Consequently, we argue that future emissions from steel are driven not by long-lived capital but by the deployment pace of novel technologies and renewable energy provision, and a reduction of steel and energy demand. Without rapid progress in these aspects, the operation of current steel production equipment is likely to consume significant amounts of the remaining carbon budget. We recommend monitoring of emission-intensive asset aging and regulation of their operation.