Reducing GHG emissions from traditional livestock systems to mitigate changing climate and biodiversity
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
Springer International Publishing Switzerland
Abstract
Climate change (CC) directly impacts the economy, ecosystems, water
resources, weather events, health issues, desertification, sea level rise, and even
political and social stability. The effects of CC affect different groups of societies
differently. In Tanzania, the effects of CC have even acquired a gender dimension,
whereby women are viewed as more vulnerable than men because of socioeco-
nomic and historic barriers. CC is largely caused by anthropogenic activities,
including those that increase the concentrations of greenhouse gases (GHGs) in
the atmosphere. Recent findings indicate that the livestock sector is responsible for
18 % of GHG emissions measured in the CO 2 equivalent. Moreover, some gases
emitted by livestock have higher potential to warm the atmosphere than CO 2 and
have a very long atmospheric lifetime. Methane (CH 4 ) has 23 times the global
warming potential (GWP) of CO 2 , whereas nitrous oxide (N 2 O) has 296 times the
GWP of CO 2 . It is now estimated that the atmospheric concentrations of CH 4 and
N 2 O are increasing at a rate of approximately 0.6 % and 0.25 % per year, respec-
tively. Cattle may emit CH 4 from enteric fermentation equivalent to 2–12 % of the
ingested energy, whereas produced manure can emit N 2 O up to 1.25 % of its
weight. The estimated total CH 4 and N 2 O emissions from Tanzanian ruminants stand at 26.17 Gg and 0.57 Gg, respectively. In this paper, we first very briefly
review emissions of GHGs from different livestock production systems in Tanzania
with the view of identifying the main hot spots. Then, we concentrate on the
available adaptation options and the limitations on the adoption of such adaptation
options in Tanzania. Emission of these GHGs per unit product varies with the level
of intensification, the types of livestock kept, and manure management. Intensifi-
cation of livestock production reduces the size of the land required to sustain a
livestock unit and frees up the land necessary for carbon sequestration. In Tanzania,
such intensification could take the form of the early harvesting and storing forage
for dry-season feeding. The advantage of this intervention is twofold: young
harvests have higher digestibility and emit less CH 4 when fed to ruminants than
mature lignified forage; use of stored roughage in the dry season will reduce the
desertification of rangeland and deforestation that occur when livestock search for
pastureland. Dry-season supplementation of ruminants with energy and protein-rich
diets will reduce CH 4 emission. The chemical treatment of crops byproducts will
increase the crops’ digestibility and reduce CH 4 emission from ruminants. Cross-
breds of indigenous and exotic breeds are more efficient converters of feed into
products like meat and milk, with less GHG emitted per unit product. The use of
manure for biogas production will reduce the emission of both CH 4 and N 2 O into
the atmosphere. Shifting from liquid to solid manure management has the potential
to reduce CH 4 emissions. Most of these interventions, however, are not cost
neutral – enhancing awareness alone will not lead to their widespread adoption.
In the absence of subsidies, the adoption of these interventions will depend on the
relative cost of other options. Although some traditional livestock systems in
Tanzania are already coping with the impact of CC, such efforts are handicapped
by inadequate resources, poor coordination, and implementation of competing
measures.
Description
Book chapter
Keywords
Livestock production, Global warming, Climate change, Adaptation strategies