Agriculture Reference
In-Depth Information
conducted for industrial materials and manufac-
tured products, and recent years have seen a
rapid expansion of LCAs being conducted in
agricultural production. There is rapidly expand-
ing interest in LCA by the livestock industries,
particularly by the beef and dairy sectors.
In animal agriculture, a partial LCA is often
used to examine the product system up to the
farm-gate because with meat, milk and eggs,
most (>70%) of the emissions are from farm-
related activities (inputs and on-farm activities),
rather than the post-farm-gate activities of man-
ufacturing, retailing and consumption. As farm
activities are usually independent of down-
stream activities beyond the farm gate, changes
in farm management to reduce environmental
impact can carry through to the final product.
In contrast, partial LCAs are usually avoided for
manufactured goods because of the unintended
potential of shifting the environmental burden
to another part of the system. However, for most
livestock products, a farm-gate LCA does not
'shift the problem' to another stage of the prod-
uct's life cycle because in most cases farming
activities are completely separate from manufac-
turing and retailing of the final product.
While LCAs may be useful for comparing
the environmental performance of manufac-
tured products, these comparisons can be very
misleading for livestock products. The complex-
ity of livestock farming systems, combined with
the differences in methodologies of estimating
the environmental impact of the farming sys-
tem across studies makes it difficult to compare
environmental performance of livestock pro-
duction across animal production systems used
worldwide.
One of the most useful outcomes of con-
ducting an LCA for animal production is to iden-
tify opportunities for improving environmental
performance within a production system. An
LCA can help identify components or processes
within the production cycle that should be tar-
geted to reduce environmental impact. For
example, Beauchemin
et al
. (2010) conducted a
farm-level LCA of GHG emissions from beef pro-
duction in western Canada. The LCA indicated
that the largest contributing GHG in beef pro-
duction was enteric methane (CH
4
) accounting
for 63% of total emissions, with about 84% of
the enteric CH
4
from the cow-calf herd, mostly
from mature cows. The LCA led the authors to
conclude that research into mitigation practices
to reduce GHG emissions from beef production
should focus on reducing enteric CH
4
produc-
tion from mature beef cows. It was thus shown
that a proportional reduction in emissions from
the cow-calf system would reduce whole-farm
emissions by about four times as much as the
same reduction in the feedlot system.
LCA can help decision making in terms of
setting priorities for research and policy, as well
as help prioritize mitigation options. For exam-
ple, a change in the animal's diet might be rec-
ommended as a means of reducing enteric CH
4
,
but the change in diet may also lead to increased
nitrous oxide (N
2
O) from fertilizers used to pro-
duce the feed. A particular farming practice
may appear to be a valid means of reducing
GHG emissions from livestock production, but
the complex interactions and feedbacks among
farming practices can make it difficult to assess
the net impact of the change. An LCA approach
can be used to integrate the entire system,
accounting for all changes in GHG emissions
and removals arising from a prospective mitiga-
tion practice, such that the true impact of a
change in practice can be fully evaluated (Janzen
et al
., 2006).
Components of Life Cycle
Assessment
LCA is conducted according to published inter-
national standards (14040 series; Life Cycle
Assessments) developed by the ISO in 2006. The
ISO is a private organization that aims to stand-
ardize and integrate quality aspects into busi-
ness practices worldwide (Guinée
et al
., 2002).
The ISO (2006) standards can be used to deter-
mine the potential environmental impact of
manufactured and agricultural products. Thus,
the basic methodology is common to all prod-
ucts; however, the goal, scope, systems bound-
ary and functional unit (FU) considered within
the LCA can differ.
We present the main characteristics of
LCA relevant to conducting farm-level LCA in
this chapter, but readers seeking detailed
methodological information on LCA should
consult the ISO 14040-14043 standards
(ISO, 2006) and the
Handbook on Life Cycle
Assessment - Operational Guide to the ISO
