The climate emergency requires the adoption of strategies and technologies that effectively reduce CO2 emissions in the short to midterm to keep the global temperature rise below 2 degrees C above pre-industrial levels. Concrete is the substance most consumed by humanity after water. The blended cements in which supplementary cementitious materials replace part of the energy-intensive clinker are the most realistic means to obtain large-scale CO2 reductions. Limestone calcined clay cements (LC3)-blended cements produced by the combination of limestone, calcined clays, and portland cement (OPC)-provides a solution that achieves equivalent mechanical performance to OPC, better durability against chloride, and alkali-silica reaction reduction of CO2 emissions by approximately 40%. Furthermore, it is cost-effective compared to OPC currently on the market. Due to the similarities with OPC, it is a material that can be adopted today using the same construction equipment and workforce worldwide.