Innovating eco-efficiency metrics: The concept of weight-related carbon intensity in the automotive sector

Large and listed companies must publish annual reports to inform about financial figures and commercial success. In recent years, these companies have also increasingly been issuing sustainability reports to provide insights into their current environmental performance and progress. However, these reports lack key figures that integrate both efficiency and environmental perspectives. Therefore, a novel indicator is proposed and tested. The weight-related carbon intensity (ciw) relates cradle-to-gate emissions to the aggregated production weight of passenger cars. Using publicly available data from five global OEMs, we demonstrate that ciw provides more robust insights into production efficiency and sustainability performance than conventional CO₂ per vehicle metrics. Our findings show that ciw can uncover inefficiencies that remain hidden under traditional reporting. The results highlight the need for weight-adjusted benchmarks in the automotive sector and suggest that ciw can serve as a complementary metric for corporate reporting, enhance emissions tracking and support climate action by expressing another CO₂ truth.