Industrial CO2 Emissions, Climate Change, and Human Health: Decarbonization Pathways in Iron and Steel Production

The iron and steel industry is one of the most energy- and emission-intensive industrial sectors, accounting for approximately 95% of global metal production and 7–9% of global CO2 emissions. Its decarbonization is therefore central to climate change mitigation and has potential co-benefits for environmental quality and human health through reductions in air pollutants associated with conventional coal-based steelmaking. This review addresses the following question: which technological and systemic pathways can reduce emissions from iron and steel production, and what constraints limit their deployment across regions? The article synthesizes current knowledge on the dominant blast furnace–basic oxygen furnace and electric arc furnace routes, their emission intensities, and their role in global steel production. It then evaluates two complementary groups of decarbonization pathways: optimization of existing carbon-intensive processes and the transition to low- and near-zero-carbon technologies, including hydrogen-based direct reduction, electrification, carbon capture, utilization and storage. Particular attention is given to the dependence of these pathways on low-carbon electricity, hydrogen availability, scrap supply, infrastructure, policy frameworks, and regional economic conditions. The review highlights that technological readiness alone is insufficient to ensure deep decarbonization; implementation depends on the alignment of energy systems, industrial investment cycles, and climate policy. From a public health perspective, steel decarbonization should be understood as a climate mitigation measure with potential health co-benefits, particularly where it reduces both greenhouse gas emissions and local air pollution.