Carbon Footprint: Concept, Methodology and Calculation
3
and product level and also the related reference documents. In Sect. 3 attention is
focused on the methodologies developed to calculate CF of products, also presenting
an overview of the Product Environmental Footprint methodology proposed by the
European Commission. Section 4 discusses the main critical issues in defining the
CF model, focusing on key aspect such as the functional unit and the temporal
dimension of the assessment, and also on modeling approaches and relevant—and
debated—GHG emission sources. Finally, in Sect. 5 an analysis of publicly available
CF calculators focused on different themes, also through a review of relevant related
literature, is presented, in order to provide an overall insight into the typology of the
available tools and the characteristics of the currently used approaches.
2 A General Overview on Carbon Footprint
In the last years, the concept of carbon footprint (CF), has been used widely as an
indicator of environmental sustainability. CF refers to the total amount of greenhouse
gas (GHG) emissions directly or indirectly produced by an activity or accumulated
during a product life cycle and can be used to evaluate the main environmental
hotspots and the mitigation or improvement measures [55, 60].
The concept of CF originated as a subset of “ecological footprint”, which refers to
the amount of productive land and sea area, expressed in hectares, to sustain human
population [60, 81]. In this context, CF can be expressed as the land area required
to assimilate the CO 2 produced by humanity. However, due to the importance of the
global warming problem in the world environmental policy and actions, the use of
CF became independent from the ecological footprint [60, 17]. Carbon footprinting
has been used in the last years but in a slightly different way, i.e. a life cycle impact
category indicator, named global warming potential (GWP) [21]. The present form of
CF is thus a hybrid concept, stemming from “ecological footprint” but representing
an indicator for GWP [60].
In fact, while an ecological footprint represents a measure of the regenerative
capacity of the environment (in terms of a corresponding area of productive land),
the present concept of CF stands for a measure of a physical quantity of carbon (or
equivalent gases) resulting from defined activities.
On the basis of this concept, CF can be defined as the CO 2 equivalent (CO 2 eq)
mass based on 100 years GWP [3, 8, 60, 85 ]. In other words, CF is quantified
by indicators such as global GWP, which is the quantity of GHGs contributing to
global warming and climate change, with a 100 years time horizon [56]. To obtain
CF results expressed in kgCO 2 eq, the actual mass of a gas has to be multiplied by
its GWP factor, in order to be able to compare the GW effect of different GHGs
[12, 22, 56].
CF allows companies to identify the most important GHG sources and to analyse
reduction potential, thus increasing productive efficiency at the same time [60, 7,
41]. In this way, environmental improvements and costs reductions can be achieved.
Due to the growing market interest for environmentally-friendly products, and the
3
and product level and also the related reference documents. In Sect. 3 attention is
focused on the methodologies developed to calculate CF of products, also presenting
an overview of the Product Environmental Footprint methodology proposed by the
European Commission. Section 4 discusses the main critical issues in defining the
CF model, focusing on key aspect such as the functional unit and the temporal
dimension of the assessment, and also on modeling approaches and relevant—and
debated—GHG emission sources. Finally, in Sect. 5 an analysis of publicly available
CF calculators focused on different themes, also through a review of relevant related
literature, is presented, in order to provide an overall insight into the typology of the
available tools and the characteristics of the currently used approaches.
2 A General Overview on Carbon Footprint
In the last years, the concept of carbon footprint (CF), has been used widely as an
indicator of environmental sustainability. CF refers to the total amount of greenhouse
gas (GHG) emissions directly or indirectly produced by an activity or accumulated
during a product life cycle and can be used to evaluate the main environmental
hotspots and the mitigation or improvement measures [55, 60].
The concept of CF originated as a subset of “ecological footprint”, which refers to
the amount of productive land and sea area, expressed in hectares, to sustain human
population [60, 81]. In this context, CF can be expressed as the land area required
to assimilate the CO 2 produced by humanity. However, due to the importance of the
global warming problem in the world environmental policy and actions, the use of
CF became independent from the ecological footprint [60, 17]. Carbon footprinting
has been used in the last years but in a slightly different way, i.e. a life cycle impact
category indicator, named global warming potential (GWP) [21]. The present form of
CF is thus a hybrid concept, stemming from “ecological footprint” but representing
an indicator for GWP [60].
In fact, while an ecological footprint represents a measure of the regenerative
capacity of the environment (in terms of a corresponding area of productive land),
the present concept of CF stands for a measure of a physical quantity of carbon (or
equivalent gases) resulting from defined activities.
On the basis of this concept, CF can be defined as the CO 2 equivalent (CO 2 eq)
mass based on 100 years GWP [3, 8, 60, 85 ]. In other words, CF is quantified
by indicators such as global GWP, which is the quantity of GHGs contributing to
global warming and climate change, with a 100 years time horizon [56]. To obtain
CF results expressed in kgCO 2 eq, the actual mass of a gas has to be multiplied by
its GWP factor, in order to be able to compare the GW effect of different GHGs
[12, 22, 56].
CF allows companies to identify the most important GHG sources and to analyse
reduction potential, thus increasing productive efficiency at the same time [60, 7,
41]. In this way, environmental improvements and costs reductions can be achieved.
Due to the growing market interest for environmentally-friendly products, and the