## 1 Introduction  
Continuous greenhouse gas (GHG) emissions from human activities have been one of the most severe environmental problems for decades [1]. In fact, worldwide carbon dioxide emissions were 35.34 Gton in 2021, while carbon dioxide concentration was about 414 ppm [2], and it is foreseen that this parameter will rise to 450 ppm in 2035 if proper actions are not taken [3]. On the other hand, due to the importance of this problem for all humanity, the research community has agreed to keep the carbon dioxide concentration value below 350 ppm for safe considerations [4]. In this context, the European Commission decided to reduce greenhouse gas emissions of 40% by 2030 and 80% by 2050 compared to the level of 1990 [5]. In this way, the increase in temperature should be kept below 2 \({}^{\circ}\)C, as signed by 200 parties in the Paris Climate Agreement conference held in 2015 (COP21) [6], and climate neutrality should be the objective to be achieved. To achieve this purpose, carbon supply chains have an important role and can be considered a strategic solution because they contribute to carbon neutrality by facilitating extensive carbon emission reductions. In fact, the reduction in carbon dioxide emissions requires not only a transition toward renewable energy supply but also the implementation of carbon supply chains. Among these systems, it is possible to have a carbon capture and utilization (CCU) supply chain, carbon capture and storage (CCS) supply chain, and carbon capture utilization and storage (CCUS) supply chain. In these frameworks, respectively, carbon dioxide is captured at the source with different capture technologies, and after its transportation, it is used to produce valuable products (i.e., oil and gas recovery, fuels and chemicals such as methanol, methane, ethanol, urea, polymers, etc., and carbon dioxide can be used for mineralization); it is stored; and it is stored and/or used in the last case ([PERSON] et al., 2015; [PERSON] et al., 2014). The importance of carbon supply chains for carbon dioxide emission reduction has been underlined by the International Energy Agency (IEA) predicting, particularly, that the CCUS system can contribute to 19% reduction in GHG emissions by 2070 by reducing 6.9 Gton\({}_{\text{CO2 eq}}\)/year [7]. Considering specifically the European Union (EU), the CCUS supply chain can contribute to an emission reduction with values of 20-604 Mton\({}_{\text{CO2}}\)/year in 2030, 140-1570 Mton\({}_{\text{CO2}}\)/year in 2040, and 430-2230 Mton\({}_{\text{CO2}}\)/year in 2050, respectively [8]. It is evident that the achievement of carbon neutrality by the mid-21 st century will be impossible without CCUS frameworks ([PERSON] et al., 2022). Moreover, the Intergovernmental Panel On Climate Change (IPCC) estimates that achieving global climate goals would be 138% more expensive without the CCUS deployment--incorporating CCUS technologies into decarbonization packages reduces the overall cost of decarbonization [9]. Due to the importance of carbon supply chains, inside the scientific community, it has been suggested to evaluate their environmental impact and verify if they are really favorable from an environmental viewpoint. In fact, despite the benefits underlined above, the overall system also consumes a lot of energy (with a consequent environmental burden) while reducing carbon dioxide. To conduct this evaluation, several 'green' metrics can be considered: atom economy, E-factor, EQ-factor, and life cycle assessment (LCA) [10]. Among them, the life cycle assessment is a holistic methodology that transforms all inputs and outputs of a considered process into impact categories considering the entire life. The environmental impact developed considering all life of a process is one of the most important methodologies and by considering a holistic perspective, the method is recognized as the most favorable green metric for an environmental analysis of a system.