Abstract <p>Hydrogen is a global, cross-cutting enabler for decarbonization, including in clean energy systems, transportation, and industry. Owing to the current cost and development level of technology, steam methane reforming (SMR) is widely used for large-scale hydrogen production. SMR is highly energy intensive and a significant source of CO₂ emissions, contrary to sustainability. In this paper, we provide a critical review of the status of SMR, focusing on scientific advances, environmental challenges, and its role in future hydrogen economies. A literature review was performed to study catalyst progress, reformer tube development, process optimization and carbon management strategies. It is compared with emerging hydrogen production processes such as electrolysis and methane pyrolysis. An increase in the hydrogen yield and resistance to catalyst deactivation are also achieved via the use of advanced nanostructured catalysts as well as membrane-based reformer tubes. SMR’s challenging scaling down to low-carbon (blue) hydrogen can greatly benefit the integration of carbon capture and storage (CCS). Although electrolysis is emission-free, SMR is an economic option when natural gas and CCS infrastructures are available. Innovation and CCS deployment will allow early-stage development of the SMR role in hydrogen scale-up. They offer a bridge to a fully decarbonized hydrogen future that has practical applications. SMR, which is upgraded with efficient catalysts and coupled with CCS, continues to be critically important for the hydrogen economy. However, the environmental impact of these sunk costs could be maximized, provided that strategic investments are made in technology and policy.</p>