Layer analysis of CO2 sources in the US economic supply chains: an input output LCA study
| Published date | 04 December 2017 |
| Pages | 2171-2193 |
| Date | 04 December 2017 |
| DOI | https://doi.org/10.1108/IMDS-11-2016-0473 |
| Author | Gokhan Egilmez,N. Muhammad Aslaam Mohamed Abdul Ghani,Ridvan Gedik |
| Subject Matter | Information & knowledge management,Information systems,Data management systems,Knowledge management,Knowledge sharing,Management science & operations,Supply chain management,Supply chain information systems,Logistics,Quality management/systems |
Layer analysis of CO
2
sources in
the US economic supply chains:
an input output LCA study
Gokhan Egilmez
Mechanical and Industrial Department of Engineering, University of New Haven,
West Haven, Connecticut, USA
N. Muhammad Aslaam Mohamed Abdul Ghani
North Dakota State University, Fargo, North Dakota, USA, and
Ridvan Gedik
Mechanical and Industrial Department of Engineering, University of New Haven,
West Haven, Connecticut, USA
Abstract
Purpose –Carbon footprint assessment requires a holistic approach, where all possible lifecycle stages of
products from raw material extraction to the end of life are considered. The purpose of this paper is to develop
an analytical sustainability assessment framework to assess the carbon footprint of US economic supply
chains from two perspectives: supply chain layers (tiers) and carbon footprint sources.
Design/methodology/approach –The methodology consists of two phases. In the first phase, the data
were collected from EORA input output and environmental impact assessment database. In the second phase,
48 input-output-based lifecycle assessment models were developed (seven CO
2
sources and total CO
2
impact,
and six supply chain tiers). In the third phase, the results are analyzed by using data visualization, data
analytics, and statistical approaches in order to identify the heavy carbon emitter industries and their
percentage shares in the supply chains by each layer and the CO
2
source.
Findings –Vast majority of carbon footprint was found to be attributed to the power generation, petroleum
refineries, used and secondhand goods, natural gas distribution, scrap, and truck transportation. These
industries dominated the entire supply chain structure and found to be the top drivers in all six layers.
Practical implications –This study decomposes the sources of the total carbon footprint of US economic
supply chains into six layers and assesses the percentage contribution of each sector in each layer. Thus, it
paves the way for quantifying the carbon footprint of each layer in today’s complex supply chain structure
and highlights the importance of handling CO
2
source in each layer separately while maintaining a holistic
focus on the overall carbon footprint impacts in the big picture. In practice, one size fits all type of policy
making may not be as effective as it could be expected.
Originality/value –This paper provides a two-dimensional viewpoint for tracing/analyzing carbon
footprint across a national economy. In the first dimension, the national economic system is divided into six
layers. In the second dimension, carbon footprint analysis is performed considering specific CO
2
sources,
including energy production, solvent, cement and minerals, agricultural burning, natural decay, and waste.
Thus, this paper contributes to the state-of-art sustainability assessment by providing a comprehensive
overview of CO
2
sources in the US economic supply chains.
Keywords Carbon footprint, Input-output analysis, Sustainable development, Policy making,
Lifecycle assessment, Green supply chains
Paper type Research paper
1. Introduction
1.1 Sustainable manufacturing and services and climate change
Sustainable development has gradually become the cornerstone topic in the last three
decades for both profit and nonprofit organizations across the world. It is typically termed
as the set of development initiatives that meets the requirements of social and economic
needs of current times without putting the future in danger, not harming the environment
and ecosystem. Even though the earth and ecosystems were functioning sustainably prior
to industrial revolution, industrial activities, which changed the production trends and
Industrial Management & Data
Systems
Vol. 117 No. 10, 2017
pp. 2171-2193
© Emerald PublishingLimited
0263-5577
DOI 10.1108/IMDS-11-2016-0473
Received 2 November 2016
Revised 13 January 2017
Accepted 19 February 2017
The current issue and full text archive of this journal is available on Emerald Insight at:
www.emeraldinsight.com/0263-5577.htm
2171
An input
output LCA
study
consumption choices, have become among the most influential factors on the climate change
and global warming. In fact, although the industrial revolution and the technological
advancements created unimaginable value to humanity, the environmental and ecological
impacts of advancements were not responsibly addressed until the end of twentieth century.
Manufacturing of goods and provision of services provide significant support to ease the
daily activities of people whether for leisure or for a necessary need, the environmental
implications that come along with the industrial processes still cause substantial problems,
which result in mid- and end-point impacts including global warming, ozone depletion, loss
of species, loss of quality life and fertility, etc.
1.2 Lifecycle assessment (LCA)
The well-known methodology, LCA, is commonly used to assess the environmental impacts
that go along with the entire lifecycle of a product including raw material extraction,
manufacturing processes (production phase), distribution, use, and end of life phases. LCA
is a robust and systematic assessment approach which can quantify the selected
environmental impacts to be used to evaluate/reduce the environmental degradation
(Mohamed Abdul Ghani et al., 2017). LCA has been used extensively today and grown
rapidly in terms of activity and interest, which is typically used to asses various products
and/or industrial sectors (Westkämper, 2000). Several LCA approaches exist in the
literature. The LCA models can be divided into three categories, namely: process
LCA (P-LCA), input-output LCA (I-O LCA), and hybrid LCA (Kucukvar and Tatari, 2011).
P-LCA deals with the impacts that occur at the process level, whereas I-O LCA methods
account for both the processes and the impacts at the local, regional, national or global scale
considering the supply chains. Hybrid LCA models are used for products where process and
supply chain-level impacts are traced by P-LCA and I-O LCA in an integrated framework.
1.3 I-O LCA
I-O models are widely used LCA approaches to assess the sustainability impacts at the
macro-economic level considering the inter-industrial linkages on an economic system.
Their motivation comes from using the I-O economic transaction tables of a regional,
national, or global economy and integrating them with the environmental impact multipliers
by using linear algebraic formulations (Kucukvar et al., 2014). It was based on Leontief’s
assumption of complicated interactions within an economy that can be approximated by
proportionality relationship (Mohamed Abdul Ghani et al., 2017). I-O LCA modeling is a
robust way to quantify both the on-site (direct) and supply chain (indirect)-level impacts
associated with the industrial activities (Egilmez et al., 2016). Because, while P-LCA models
can bring the difficulty of obtaining quantitative data depending on the problem, I-O LCA
approaches bring the data availability advantage to the LCA studies due to its ability to deal
with macro-level impacts and providing a more holistic picture about the entire extent of
socio-economic and environmental impacts. The main drawback of I-O LCA models is the
impact of uncertainty in the results due to aggregation in macro economy-level estimations.
And, this phenomenon is quite normal and acceptable as the scope of the assessment gets
larger for instance from local (e.g. a city), regional (e.g. a state), national, to the globe
(global trade). However, being sure about a smaller part of the problem such as the tail of the
elephant is less advantageous and riskier ( from policy-making perspective) compared to
being sure with some level of uncertainty about the size of the entire elephant. Therefore, I-O
LCA is an appropriate method in order to trace supply chain-level impacts in addition to the
on-site (process level) impacts from a macro-economic perspective. And, industrial supply
chain network in an economy can easily be modeled with I-O analysis, where an industry
has theoretically Nlayers in its supply chains, in an economic system that consists of N
industries. An example of layers in a typical economy is illustrated for industrial sector i,
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