The built environment accounts for nearly 40% of global CO₂ emissions, much of it embedded in materials before a building is even used. As operational energy improves, embodied carbon now defines a building’s true climate impact. Global building floor area is projected to double by 2060, adding nearly 230 billion square metres of new construction. As buildings become more energy efficient, embodied carbon can account for up to 50–70% of a new building’s total lifetime emissions, particularly in the first decades after construction. Early design decisions therefore carry lasting environmental consequences. Carbon- conscious material choices are central to responsible architecture.