With a globalized economy, while consumption of products takes place in some parts of the world, manufacturing and consumption occur in different parts of the world. However, the scope of the traditional sustainability assessment studies is predominantly at product level and does not address macro-level impacts and cannot capture a majority of upstream supply chain impacts due to narrowly defined ‘System Boundaries’, which is also known as the cut-off criteria. To promote sustainable consumption and production policies and to understand the social, economic and environmental effects of consumption, there is a dire need to capture whole sustainability impacts across international supply chains using a systemic approach. The importance of consideration of all indirect supply chain-related impacts (is also called economy-wide macro-level analysis) within the sustainability science is emphasized in the past as inter-related global sustainability issues require more holistic approaches in which the macro-level impacts (economy-wide, or global) covering entire supply chain is essential to reveal sustainability impacts of products, services, or systems. This is because process-based models involve a limited number of processes without tracing the entire supply chains of products, and the inclusion or exclusion of processes is decided on the basis of subjective choices, which create the so-called system boundary problem. Past studies on the environmental footprint of sectors also showed that process-based models neglecting indirect regional and global supply chains suffer from significant truncation errors, which can be of the order of 50% or higher.
At this point, Multi Region Input–Output (MRIO) models can be a better modelling approach in the estimation of sustainability impacts of production and consumption at global scale. MRIOs can be a superior method for extending the scope from a regional economy to global economy. This research will discuss the importance of enlarging the system boundary in sustainability assessment of production and consumption from micro level to macro-level analysis. A web-based Global Carbon Footprint Accounting Tool (GCAT, http://s3-lab.sehir.edu.tr/gcat) will be introduced for presenting real case studies for sustainability analytics of manufacturing and service industries from world’s major economies. Finally, we discuss the importance of integrated system-based methods for advancement of sustainability assessment framework towards regional and global level analysis using multi-region input-output analysis that is capable of quantitatively capturing macro-level social, environmental, and economic impacts.