Iron and steel production is responsible for 7% of global greenhouse gas emissions. Previous research has found that the long economic life of steel production equipment impedes decarbonization in line with climate targets.

The authors estimated the cumulative emissions from existing primary steel production equipment if operated as historically observed, based on furnace-level data of historical operating patterns. They report that the emissions commitment of current primary steel equipment is significantly smaller (21 Gt CO2eq) than previously suggested (52–65 Gt CO2eq). Consequently, they argue, future emissions from steel are driven not by long-lived capital, but by the pace of deployment of novel technologies and renewable energy provision, as well as a general reduction of steel demand and energy use.

Without rapid progress in these fields, the operation of current steel production equipment is likely to consume significant amounts of the remaining carbon budget. The authors recommend better monitoring of the age of emission-intensive assets and more research to examine how the operation of such equipment can be regulated.