The production of steel, a key enabler of modern societal development, is responsible for over a quarter of industry's carbon dioxide (CO 2) emissions (IEA, 2016). The International Energy Agency's (IEA) 2ºC scenario for 2050 suggests that more than a third of the emissions reduction in industry (excluding power generation) will come from the steel sector, making steel the single largest contributor to industrial emissions reduction. Energy efficiency (EE) and material efficiency (ME) strategies, the combination of which is defined as resource efficiency (RE) in this article, are expected to deliver significant emissions reductions in the short term, especially while decarbonisation technologies such as smeltreduction and carbon capture and storage are still under development. In fact, in their Material Efficiency Scenario, the (IEA, 2015a) shows "material efficiency could deliver larger energy savings in energy-intensive industries than energy efficiency" especially in the steel industry. Customarily, to determine the improvement potential available from EE, the scale of the energy flows in a system is traced, and both a current and a target efficiency are defined. Yet performing a similar task for industry, where the main product outputs are materials, cannot be appropriately accomplished by solely evaluating the flows and efficiency of energy. In real industrial processes, including steelmaking, material and energy inputs interact and undergo chemical reactions to produce a range of energy and material products. Neglecting materials when analysing industrial RE only provides a myopic picture. To quantify the potential resource and emissions savings in the steel industry, a holistic understanding of both types of resources and appropriate metrics that capture their interactions is needed.