WASHINGTON, March 5, 2014 – Livestock producers can boost
profitability and address climate change by mixing systems to include higher
quality feed and grass, rather than a pure grass-based system alone, according
to research
published in the Proceedings of the
National Academy of Sciences.
A global team of scientists representing Austria, Africa,
Australia, the Caribbean, Europe and the United States says that cows, sheep,
and goats grow more quickly and produce more milk when they eat energy-rich
diets that include grain supplements or improved forages. This means that more
livestock can be raised on less land, and with fewer emissions per pound of
meat or milk produced.
“There is a lot of discussion about reduction of meat in the
diets as a way to reduce emissions,” says Petr Havlík, a researcher with the International
Institute for Applied Systems Analysis (IIASA) in Austria, who led the study.
“But our results show that targeting the production side of agriculture is a
much more efficient way to reduce greenhouse gas emissions.”
Scientists have in the past decade determined that livestock
production is responsible for about 12 percent of human-related greenhouse gas
emissions (GHGs), mostly caused by changes in land use and deforestation undertaken
to expand grazing areas, as well as methane released by the animals themselves.
A lesser amount of emissions come from manure management and feed production,
scientists say.
Livestock provides a third of the protein in human diets. As
the middle class continues to grow in developing nations, the demand for meat
and dairy protein is expected to rise and, as a result, emissions are expected
to increase.
Some 30 percent of global land area is used to raise
livestock, and between 1980 and 2000, an estimated 80 percent of agricultural
land expansion came in tropical areas, including forestland. Much of the new
space was used to raise cattle, sheep and goats, as well as grow corn and
soybeans for animal feed.
But the new research shows that supplementing grazing with
high quality feeds could lead to a 23 percent reduction of emissions from land-use
change in the next two decades.
The new study projects that the increasing cost of land and
continued yield increases in the crop sector will lead to global shifts to
richer animal diets, which are efficient in not only reducing GHGs, but also in
profit maximization and food production.
Citing a moderate price of $10 per ton of carbon dioxide
equivalent, the study says livestock system transitions within a given region,
together with international relocation of production to regions with the most
efficient livestock systems, could also reduce the total emissions from
agriculture and land use change by 25 percent, with most of the savings coming
from avoided land use change.
“From the livestock sector perspective, limiting land-use
change seems the cheapest option both in terms of the economic cost and in
terms of impact on food availability,” Havlík says.
The study just published adds to previous work by the group that
produced a detailed database highlighting the differences in the efficiency and
greenhouse gas emissions of different livestock production systems. The study
examines the economic potential for a transition to more efficient systems as a
mitigation measure and offers policies that would be the most effective for
cutting greenhouse gas emissions, all while maintaining food availability.
Havlík and his colleagues say that improved diets for
animals would be lower in cellulose and richer in energy, and that means lower methane
emissions from flatulent animals.
The United Nations Food and Agriculture Organization says livestock
production accounts for 37 percent of the methane produced through human
activity. Over a 20-year time frame, methane is 70 times more powerful than the
oft-cited GHG, carbon dioxide.
Methane, scientists say, also has a much shorter half-life –
eight years – compared to the 100 years half-life of carbon dioxide. As a
result, any reduction in methane has a much more immediate impact – a critical
attribute given what research shows is the speed with which major climate
disruptions have been occurring over the past several decades, including
extensive floods and widespread drought.
The IIASA study also introduces a new metric for measuring
the costs of climate measures for agricultural systems. The so-called Total
Abatement Calorie Cost (TACC) complements the pure economic metric known as
“marginal abatement cost,” while also capturing the impacts of mitigation
measures on food security.
Mario Herrero, a co-author of the study, says that applying
current metrics could lead to mitigation, but also food insecurity in
developing countries, because it ignores the social cost of policies that focus
just on greenhouse gas abatement.
"So we developed a new metric which tells you how
consumption would be affected as a result of mitigating greenhouse gas
emissions,” she said.
Changing livestock production systems remains a challenge, the
researchers say, noting that policies that provide education and market access
are the keys for enabling change. In addition, they say safeguards are needed
to insure that the growing intensity in production cited by their study does
not lead to environmental damage or reduce animal well-being.
#30
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