Agriculture Reference
In-Depth Information
Table 15.1
Greenhouse
gases' global warming
potential when expressed as
a factor of carbon dioxide
(whose GWP is standard-
ized to 1)
Green House Gas (GHG)
Global Warming Potential
(GWP)
CO
2
(carbon dioxide)
1
CH
4
(methane)
25
N
2
O (nitrous oxide)
298
Life Cycle Assessment
The International Standards Organisation defines Life Cycle Assessment (LCA) as
a “compilation and evaluation of the inputs, outputs and the potential environmental
impacts of a product system throughout its life cycle” (Anon
2006
). LCA quanti-
fies the environmental burdens of a product or service during its lifetime. This tool
has recently gained significant ground and has been largely accepted by the scien-
tific community (Ingram and Fernandez
2012
). Conducting an LCA can aid in the
creation of a robust benchmark to reduce Green House Gases (GHG) emissions,
whilst employing LCA to identify inputs with large environmental burdens used in
a process, for example potential pesticide pollution or the breakdown rate of plastic
propagation bags in the environment. LCAs are key to good environmental manage-
ment and in reducing GHG emissions and its impact on global warming.
There are several aspects to calculating a 'footprint' of a process. Calculating
an environmental footprint enables stakeholders, for example, growers, legislative
bodies or consumers, to be able to quantify and compare a product's impact with
another. Carbon foot printing is one of the principal and most common elements
of LCA. It quantifies the GHG emitted by a product or service (Anon 2011). Car-
bon footprints are expressed in kilograms of CO
2
e. This allows other GHGs to be
compared and measured on the same level (Table
15.1
). An inventory analysis is a
fundamental element of LCA. Figure
15.2
provides a schematic representation of a
Life Cycle Assessment, showing how inputs and outputs impact within a predefined
boundary.
Ingram and Fernandez (
2012
) state that carrying out an LCA on horticultural pro-
cesses is difficult to access because of the little information regarding the “ diverse
yet specific set of inputs” associated with horticulture. For example they illustrate
that there is a variation of 85 % in the carbon footprint between ammonium nitrate
and urea used in horticultural production.
Environmental Footprint
Additionally, when compared with other food production systems such as livestock
and arable agricultural land, there has been limited investigation on the environmen-
tal and social impact of production horticulture. A study in the UK by Lillywhite
et al. (
2007
) commissioned by DEFRA, constructed environmental footprints for 12
