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Researchers question sustainability of livestock


October 12, 2010
By Manure Manager

October 8, 2010, Halifax,
NS – A new paper released by Nathan Pelletier and Peter Tyedmers of the
Dalhousie University School for Resource and Environmental Studies raises some
thought-provoking questions about consumption and production in our food
systems and in particular, the livestock industry.

October 8, 2010, Halifax,
NS – A new paper released by Nathan Pelletier and Peter Tyedmers of the
Dalhousie University School for Resource and Environmental Studies raises some
thought-provoking questions about consumption and production in our food
systems and in particular, the livestock industry.

Pelletier, a
self-confessed “foodie” and ecological economist is interested in studying food
systems and how they effect the environment both at the local and global
levels. “Food is a really unique area of consumption in that we have a great
deal of control over what and how much we choose to consume,” says Pelletier.
“As a result, we also have direct control over the environmental implications
of our dietary choices.”

Focusing on the global
livestock industry, Pelletier and Tyedmers’ paper explores the relationships
between projected growth in livestock production and worldwide sustainability
thresholds for human activity as a whole. The paper focuses on three domains:
greenhouse gas emissions, reactive nitrogen mobilization and appropriation of
plant biomass.

Pelletier and Tyedmers’
research focuses on the 50 year period between 2000 and 2050. Using published
data of the environmental impact of livestock production from the year 2000 and
projections of livestock production and consumption from the United Nations
Food and Agriculture Organization
, the authors were able to estimate the
potential environmental impacts in the 50 year period.

The news is not great.

It is estimated that
global production of livestock will double in the next 50 years, which will in
turn, greatly increase the environmental impacts of the livestock industry.
Pelletier and Tyedmers estimate that the livestock industry alone will account
for 72 percent of humanity’s total “safe operating space” for anthropogenic
greenhouse gas emissions, 88 percent of safe operating space for biomass
appropriation and nearly 300 percent of the safe operating space for reactive
nitrogen mobilization.

Nitrogen plays a pivotal
role in both our natural and agricultural ecosystems. It is the most abundant
element in our atmosphere, but when the nitrogen cycle is overloaded, the
consequences can be very serious. An abundance of nitrogen can lead to
ecosystem simplification and a loss of biodiversity as well as contribute to
global warming, acid precipitation and eutrophication of bodies of water.
Industrially fixed nitrogen is a large component of commercial fertilizer but
it is estimated that only 10 to 20 percent of the nitrogen applied to crops is
actually consumed by humans. The remainder is lost to the environment. While
reactive nitrogen is not directly used in livestock production, it is used to
fertilize the crops and pastures that feed livestock.

It is estimated that
nearly 60 percent of the biomass currently harvested annually to support all
human activities is consumed by the livestock industry. This underscores the
dependence of this industry on biological productivity and raises some serious
questions about the sustainability of devoting such a large portion to the
livestock industry.

This doesn’t mean that you
should immediately stop eating burgers and steak and become a strict
vegetarian. Human beings need protein to survive and livestock is a valuable
source of protein and other nutrients. There are, however, also many other
sources of protein that have the potential for a far less dramatic impact on
the earth.

For example, Pelletier and
Tyedmers’ paper also examines similar environmental projections that explore
the implications of a shift away from livestock production to a more low impact
source of protein such as poultry or soybeans. Although the authors stress that
a total switch to poultry or soybeans is unrealistic, even a marginal decrease
in livestock production would help to reduce environmental impact.

As consumers, we can also
make a difference. “It is very well established that making changes in our
diets can help reduce our individual and collective environmental impacts. What
we need to focus on is a change in expectations. We need to re-establish
appropriate levels of consumption in developed countries (where overconsumption
of livestock products is prevalent), and curtail the rise of diets overly
dependent on livestock products in the developing world. This will have both
health and environmental benefits,” says Pelletier.


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