Efficiency stagnation in global steel production urges joint supply- and demand-side mitigation efforts

Steel production is a difficult-to-mitigate sector that challenges climate mitigation commitments. Efforts for future decarbonization can benefit from understanding its progress to date. Here we report on greenhouse gas emissions from global steel production over the past century (1900-2015) by combining material flow analysis and life cycle assessment. We find that similar to 45 Gt steel was produced in this period leading to emissions of similar to 147 Gt CO2-eq. Significant improvement in process efficiency (similar to 67%) was achieved, but was offset by a 44-fold increase in annual steel production, resulting in a 17-fold net increase in annual emissions. Despite some regional technical improvements, the industry's decarbonization progress at the global scale has largely stagnated since 1995 mainly due to expanded production in emerging countries with high carbon intensity. Our analysis of future scenarios indicates that the expected demand expansion in these countries may jeopardize steel industry's prospects for following 1.5 degrees C emission reduction pathways. To achieve the Paris climate goals, there is an urgent need for rapid implementation of joint supply- and demand-side mitigation measures around the world in consideration of regional conditions. The effectiveness of large historical efforts for decarbonizing steel production is unclear. Here, the authors show that such efficiency gains were offset by a booming steel demand increase. This has led to a stagnating decarbonization progress over past decades, which jeopardizes realization of future climate targets.

Automated summary

Steel production is a challenging sector for climate mitigation efforts due to its difficulty in reducing emissions. Despite improvements in process efficiency, the increase in steel production has led to a corresponding increase in emissions. The industry's decarbonization progress has stagnated globally since 1995, primarily due to expanded production in emerging countries with high carbon intensity.