MatMat – Hybrid Input-Output framework to estimate country-level carbon and material footprints in future scenarios

As nations intensify efforts to design and implement low-carbon strategies, aligning these with the broader sustainability objectives of the Sustainable Development Goals (SDGs) becomes essential. These strategies must extend beyond mere territorial decarbonization to include comprehensive assessments using local indicators that accurately reflect the sustainability of global supply chains. However, a significant gap exists in modeling tools capable of assessing economy-wide sustainability for future scenarios at national scale. This paper introduces the MatMat Hybrid Input-Output (HIO) model, a novel framework developed to assess and map country-specific carbon and materials footprints across supply chains and trade, for both current situation and future transition scenarios. Employing methods such as capital endogenization within a national context, and by integrating and reconciling diverse economic, technical, and policy projections, the model enables forward-looking analyses that are technically realistic and macroeconomically consistent. The MatMat model provides detailed insights into the factors driving the evolution of future carbon and material footprints across various final consumption sectors, differentiating between territorial contributions and those embodied in imported goods and services. Demonstrated through its application to France, the model proves invaluable for policymakers to assess the effectiveness of Net-Zero Emissions (NZE) scenarios and to identify necessary intervention areas to enhance sustainability. The architecture of the MatMat model ensures transparency, reproducibility, replicability, and extensibility, supporting its application to similar case studies in France and other countries, as well as the integration of new functionalities.