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4 Life Cycle Assessment: Nice to Have or Essential …
a footprint? Is a life cycle perspective indispensable for every footprint accounting?
In this chapter, we will discuss some of the points where environmental footprints
and LCA agree, but also some of the points where they disagree.
4.2 On the Strengths of LCA for Environmental Footprints
In this section, the strengths of LCA to support the measurement of specific
impact categories accounted to environmental footprints that are illustrated with
two examples: the carbon footprint and the material footprint.
4.2.1 The Role of Impact Characterization in the Carbon
Footprint
The ever-accelerating growth in atmospheric carbon emissions poses the greatest
anthropogenic disturbance to the Earth’s climate system. As a result, mitigating
global warming through reduction of carbon emissions receives top priority among
climate-engineering strategies (Cusack et al. 2014). In the pursuit of transitioning
to lower carbon output, the concept of the “carbon footprint” was born, with the
intention to raise consumer and stakeholder awareness by attributing the responsibility for carbon emissions to products, individuals, organizations, industries, and
nations. Although the carbon footprint is internationally recognized as a measure of
anthropogenic climate impacts, particularly in the field of LCA (Hellweg and Milà
i Canals 2014), confusion surrounding its meaning still exists.
Of particular concern is what the carbon footprint actually measures and how it
deviates from the “ecological footprint” (Borucke et al. 2013). The carbon footprint
follows the logic of the LCA framework, in which activities are first translated into
the inventory of emissions (resource extractions can be treated on the same level
of life cycle inventory) and further processed in a subsequent characterization step,
in which the inventory results (emissions or extractions) are modeled quantitatively
and expressed as impact scores according to their relative contributions to a specific
impact category. By contrast, the ecological footprint translates a given activity into
emissions and extractions that are then aggregated into land area required for absorption and regeneration, by a simple conversion that does not involve any characterization modeling. Having recognized probably the most important difference between
the carbon and ecological footprints, Hammond (2007) unexpectedly argued that the
term “footprint” implies a form of area-based indicator, and that the carbon footprint
should thus be renamed “carbon weight” due to its mass unit. This may appear to
be an argument over semantics, but underneath is a deeper issue that may indicate
a misinterpretation of the term “footprint” and of the rationale behind the carbon
footprint calculation. We discuss these issues below.
4 Life Cycle Assessment: Nice to Have or Essential …
a footprint? Is a life cycle perspective indispensable for every footprint accounting?
In this chapter, we will discuss some of the points where environmental footprints
and LCA agree, but also some of the points where they disagree.
4.2 On the Strengths of LCA for Environmental Footprints
In this section, the strengths of LCA to support the measurement of specific
impact categories accounted to environmental footprints that are illustrated with
two examples: the carbon footprint and the material footprint.
4.2.1 The Role of Impact Characterization in the Carbon
Footprint
The ever-accelerating growth in atmospheric carbon emissions poses the greatest
anthropogenic disturbance to the Earth’s climate system. As a result, mitigating
global warming through reduction of carbon emissions receives top priority among
climate-engineering strategies (Cusack et al. 2014). In the pursuit of transitioning
to lower carbon output, the concept of the “carbon footprint” was born, with the
intention to raise consumer and stakeholder awareness by attributing the responsibility for carbon emissions to products, individuals, organizations, industries, and
nations. Although the carbon footprint is internationally recognized as a measure of
anthropogenic climate impacts, particularly in the field of LCA (Hellweg and Milà
i Canals 2014), confusion surrounding its meaning still exists.
Of particular concern is what the carbon footprint actually measures and how it
deviates from the “ecological footprint” (Borucke et al. 2013). The carbon footprint
follows the logic of the LCA framework, in which activities are first translated into
the inventory of emissions (resource extractions can be treated on the same level
of life cycle inventory) and further processed in a subsequent characterization step,
in which the inventory results (emissions or extractions) are modeled quantitatively
and expressed as impact scores according to their relative contributions to a specific
impact category. By contrast, the ecological footprint translates a given activity into
emissions and extractions that are then aggregated into land area required for absorption and regeneration, by a simple conversion that does not involve any characterization modeling. Having recognized probably the most important difference between
the carbon and ecological footprints, Hammond (2007) unexpectedly argued that the
term “footprint” implies a form of area-based indicator, and that the carbon footprint
should thus be renamed “carbon weight” due to its mass unit. This may appear to
be an argument over semantics, but underneath is a deeper issue that may indicate
a misinterpretation of the term “footprint” and of the rationale behind the carbon
footprint calculation. We discuss these issues below.