Greenhouse gas emissions from concrete manufacturing are a critical issue in environmentally sustainable design (ESD). This study provides hard data on CO₂ emissions from concrete production to enable accurate estimates. The research collected data from quarries and concrete plants to quantify CO₂ emissions during concrete manufacturing and placement. Results show that Portland cement is the primary source of CO₂ emissions, accounting for 74–81% of total emissions. Coarse aggregates contribute 13–20%, with electricity being the main source (about 80%). Fine aggregates generate 30–40% of emissions compared to coarse aggregates, with diesel and electricity contributing equally. Admixtures have negligible emissions. Concrete batching, transport, and placement contribute small amounts. Concrete with Portland cement has CO₂ emissions ranging from 0.29 to 0.32 t CO₂-e/m³. Using GGBFS reduces emissions by 22%, while fly ash reduces them by 13–15%. The study highlights that while cement is the main contributor, other components also play a role. The data presented is based on typical Australian methods and can be used to compare concrete emissions with alternative materials. The study recommends using data-based models for reliable comparisons. It also presents a case study demonstrating how the results can be applied. Concrete is the most widely used construction material, with significant global consumption. Even small reductions in emissions per ton of concrete can have a major impact. The study provides CO₂ emissions data for concrete components, including cement, aggregates, and by-products like GGBFS and fly ash. The research considers energy use in production, transport, and placement, which contribute to emissions. The study emphasizes the importance of considering all components in assessing concrete's environmental impact.Greenhouse gas emissions from concrete manufacturing are a critical issue in environmentally sustainable design (ESD). This study provides hard data on CO₂ emissions from concrete production to enable accurate estimates. The research collected data from quarries and concrete plants to quantify CO₂ emissions during concrete manufacturing and placement. Results show that Portland cement is the primary source of CO₂ emissions, accounting for 74–81% of total emissions. Coarse aggregates contribute 13–20%, with electricity being the main source (about 80%). Fine aggregates generate 30–40% of emissions compared to coarse aggregates, with diesel and electricity contributing equally. Admixtures have negligible emissions. Concrete batching, transport, and placement contribute small amounts. Concrete with Portland cement has CO₂ emissions ranging from 0.29 to 0.32 t CO₂-e/m³. Using GGBFS reduces emissions by 22%, while fly ash reduces them by 13–15%. The study highlights that while cement is the main contributor, other components also play a role. The data presented is based on typical Australian methods and can be used to compare concrete emissions with alternative materials. The study recommends using data-based models for reliable comparisons. It also presents a case study demonstrating how the results can be applied. Concrete is the most widely used construction material, with significant global consumption. Even small reductions in emissions per ton of concrete can have a major impact. The study provides CO₂ emissions data for concrete components, including cement, aggregates, and by-products like GGBFS and fly ash. The research considers energy use in production, transport, and placement, which contribute to emissions. The study emphasizes the importance of considering all components in assessing concrete's environmental impact.