Nuri Cihat Onat

Tracking the environmental impacts of production, use, and disposal of products (e.g., goods, and services) have been an important issue in the global economy. Although Life Cycle Assessment (LCA) is a widely applied method to track these environmental impacts and support policies, it has certain limitations and an isolated way of evaluating the environmental impacts with no consideration of social and economic impacts and mechanisms. To overcome the limits of current LCA, three mechanisms have been proposed in the literature: (1) broadening the indicators by including social and economic indicators in addition to the environmental impacts; (2) broadening the scope of analysis from product-level assessment to national and global levels; (3) deepening the assessment by inclusion of more mechanisms to account for interrelations among the system elements, uncertainty analysis, stakeholder involvement, etc. With these developments, LCA has been evolving into a new framework called Life Cycle Sustainability Assessment (LCSA). Practical application of LCSA requires integration of various methods, tools, and disciplines. In this study, a comprehensive literature review is conducted to investigate recent developments, current challenges, and future perspectives in the LCSA literature. According to the review, a high number (40%) of LCSA studies are from the environmental science discipline, while contributions from other disciplines such as economics (3%) and social sciences (9%) are very low. On broadening the scope of analysis, 58% of the studies are product-level works, while 37% quantified the impacts at national level and achieved an economy-wide analysis, and only 5% of the studies were able to quantify the global impacts of products using LCSA framework. Furthermore, current applications of LCSA have not considered the rebound effects, feedback mechanisms, and interrelations of the system of interest sufficiently. To address these challenges, we present a complete discussion about the overarching role of systems thinking to bring tools, methods and disciplines together, and provide practical examples from the earlier studies that have employed various system-based methods. We discuss the importance of integrated system-based methods for advancement of LCSA framework in the following directions: (1) regional and global level LCSA models using multi-region input-output analysis that is capable of quantitatively capturing macro-level social, environmental, and economic impacts; (2) dealing with uncertainties in LCSA during multi-criteria decision-making process and expert judgments in weighting of LCSA indicators; and (3) integration of system dynamics modeling to reveal complex interconnections, dependencies, and causal relationships between sustainability indicators.

The main objectives of this research are to improve our understanding of energy-climate-manufacturing
nexus within the context of regional and global manufacturing supply chains as well as show the significance
of full coverage of entire supply chain tiers in order to prevent significant underestimations, which
might lead to invalid policy conclusions. With this motivation, a multi-region input–output (MRIO) sustainability
assessment model is developed by using the World Input–Output Database, which is a
dynamic MRIO framework on the world’s 40 largest economies covering 1440 economic sectors. The
method presented in this study is the first environmentally-extended MRIO model that harmonizes
energy and carbon footprint accounts for Turkish manufacturing sectors and a global trade-linked carbon
and energy footprint analysis of Turkish manufacturing sectors is performed as a case study. The results
are presented by distinguishing the contributions of five common supply chain phases such as upstream
suppliers, onsite manufacturing, transportation, wholesale, and retail trade. The findings showed that
onsite and upstream supply chains are found to have over 90% of total energy use and carbon footprint
for all industrial sectors. Electricity, Gas and Water Supply sector is usually found to be as the main contributor
to global climate change, and Coke, Refined Petroleum, and Nuclear Fuel sector is the main driver
of energy use in upstream supply chains. Overall, the largest portion of total carbon emissions of Turkish
manufacturing industries is found in Turkey’s regional boundary that ranged between 40% and 60% of
total carbon emissions. In 2009, China, United States, and Rest-of-the-World’s contribution is found to be more than 50% of total energy use of Turkish manufacturing. The authors envision that a global MRIO
framework can provide a vital guidance for policy makers to analyze the role of global manufacturing
supply chains and prevent significant underestimations due to inclusion of limited number of tiers for
sustainable supply chain management research.

This research aims to advance the existing sustainability assessment framework for alternative passenger cars with a combination of life-cycle sustainability assessment and multi-criteria decision-making. To this end, sixteen macro-level sustainability impacts are evaluated for seven different vehicle types: internal combustion vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles with all-electric ranges of 16, 32, 48, and 64 km of electric powered drive, and battery electric vehicles. Additionally, two battery charging scenarios are considered in this analysis with respect to plug-in hybrid electric vehicles and battery electric vehicles; Scenario 1 is based on existing electric power infrastructure in the U.S., while Scenario 2 is an extreme scenario in which electricity to power battery electric vehicles and plug-in hybrid electric vehicles is generated entirely via solar charging stations. In this study, optimal vehicle distributions are calculated based on the environmental, social, and economic impacts of all vehicle types for each scenario. Various distributions are presented in accordance with the relative importance assigned to each indicator, with different weighting scenarios applied to account for variability in decision-makers' priorities, such as the assignment of higher weights to socio-economic indicators (e.g. maximizing employment) and lower weights to environmental indicators (e.g. minimizing greenhouse gas emissions). In a balanced weighting case (i.e. when environmental and socio-economic indicators have equal importance) under Scenario 1, hybrid electric vehicles have the largest fleet share, comprising 91% of the optimal U.S. passenger car fleet, while internal combustion vehicles dominate the optimal fleet with 99.5% of the optimal fleet share when only socio-economic indicators are given priority. On the other hand, in a balanced weighting case under Scenario 2, the optimal U.S. passenger car fleet consists entirely (100%) of plug-in hybrid electric vehicles with 16 km of all-electric range. In the majority of the considered weighting scenarios, battery electric vehicles were not given any share of the optimal vehicle fleet. The proposed framework can be used as a practical decision-making platform when deciding which vehicle type to promote given each vehicle type's respective environmental, social, and economic impacts. Considering that decision makers are often highly influenced by the “silo effect”, i.e. a lack of communication among different agencies and departments (national or international), the proposed framework provides a holistic system-based approach to minimize the silo effect and can enhance the efficiency of future inter/cross/trans-disciplinary works. Furthermore, the outcomes of this study can pave the way for advancement in the state-of-the-art and state-of-the-practice of current sustainability research.

The World Business Council for Sustainable Development (WBCSD) and the World Resource Institute (WRI) set the scope-based carbon footprint accounting standards in which all possible supply-chain related indirect greenhouse gas emissions are captured. Although this carbon footprint accounting standards are widely used in regional policy making, there is little effort in analyzing the scope-based carbon footprints of nations using a multi-region input–output (MRIO) analysis in order to consider the role of global trade. This research aims to advance the body of knowledge on carbon footprint analysis of the manufacturing sectors with a holistic approach combining the WBCSD & WRI’s scope-based carbon footprint accounting standards with a time series MRIO framework. To achieve this goal, a global scope-based carbon footprint analysis of the Turkish manufacturing sectors has been conducted as a case study. We employed a time series MRIO analysis by using the World Input–Output Database on the world’s 40 largest economies covering 1440 economic sectors. The results showed that electricity, gas and water supply was the most dominant sector in the supply chains of the Turkish industrial sectors with the largest carbon footprint. On average, indirect emissions of the Turkish manufacturing industry are found to be higher than direct emissions during the period from 2000 to 2009. The results of this analysis revealed that supply chain related indirect emissions (represented by scope 3) are responsible for nearly 56.5% total carbon emissions of sectors, which highlights the crucial role of supply chains on overall carbon footprint of sectors.

The World Business Council for Sustainable Development (WBCSD) and the World Resource Institute (WRI) set the scope-based carbon footprint accounting standards in which all possible supply-chain related indirect greenhouse gas emissions are captured. Although this carbon footprint accounting standards are widely used in regional policy making, there is little effort in analyzing the scope-based carbon footprints of nations using a multi-region input–output (MRIO) analysis in order to consider the role of global trade. This research aims to advance the body of knowledge on carbon footprint analysis of the manufacturing sectors with a holistic approach combining the WBCSD & WRI’s scope-based carbon footprint accounting standards with a time series MRIO framework. To achieve this goal, a global scope-based carbon footprint analysis of the Turkish manufacturing sectors has been conducted as a case study. We employed a time series MRIO analysis by using the World Input–Output Database on the world’s 40 largest economies covering 1440 economic sectors. The results showed that electricity, gas and water supply was the most dominant sector in the supply chains of the Turkish industrial sectors with the largest carbon footprint. On average, indirect emissions of the Turkish manufacturing industry are found to be higher than direct emissions during the period from 2000 to 2009. The results of this analysis revealed that supply chain related indirect emissions (represented by scope 3) are responsible for nearly 56.5% total carbon emissions of sectors, which highlights the crucial role of supply chains on overall carbon footprint of sectors.

Sustainable transportation and mobility are key components and central to sustainable development. This research aims to reveal the macro-level social, economic, and environmental impacts of alternative vehicle technologies in the U.S. The studied vehicle technologies are conventional gasoline, hybrid, plug-in hybrid with four different all-electric ranges, and full battery electric vehicles (BEV). In total, 19 macro level sustainability indicators are quantified for a scenario in which electric vehicles are charged through the existing U.S. power grid with no additional infrastructure, and an extreme scenario in which electric vehicles are fully charged with solar charging stations. The analysis covers all life cycle phases from the material extraction, processing, manufacturing, and operation phases to the end-of-life phases of vehicles and batteries. Results of this analysis revealed that the manufacturing phase is the most influential phase in terms of socio-economic impacts compared to other life cycle phases, whereas operation phase is the most dominant phase in the terms of environmental impacts and some of the socio-economic impacts such as human health and economic cost of emissions. Electric vehicles have less air pollution cost and human health impacts compared to conventional gasoline vehicles. The economic cost of emissions and human health impact reduction potential can be up to 45% and 35%, respectively, if electric vehicles are charged through solar charging stations. Electric vehicles have potential to generate income for low and medium skilled workers in the U.S. In addition to quantified sustainability indicators, some sustainability metrics were developed to compare relative sustainability performance alternative passenger vehicles. BEV has the lowest greenhouse gas emissions and ecological land footprint per $ of its contribution to the U.S. GDP, and has the lowest ecological footprint per unit of its energy consumption. The only sustainability metrics that does not favor the BEV is the water-energy ratio, where the conventional gasoline vehicle performed best.