Agriculture as a Source of GHGs - Climate Resilient Agriculture for Ensuring Food Security - page 36

the farm (“post-farm gate”) is larger in high-
income countries. For example, these activi-
ties make up some 50 % of food system
emissions in the United Kingdom (Garnett
2011 ). Middle-income countries will likely
follow this trend in the future.
￿ Fisheries and aquaculture are estimated to
make only minor contributions to greenhouse
gas emissions.

1.1 kgCO 2 e/kg FPCM for high production lev-
els (about 8,000 kg of milk) (Gerber et al.
2011 ).
The global livestock sector emits almost
6,000 million metric tons of carbon dioxide
equivalents (MtCO 2 e) per year at 2008 levels
and accounts for about 11 % of global green-
house gas emissions. Emissions from the sector
are expected to increase 70 % by 2050 (PBL
2009 ).
￿ Animal protein from monogastric animals
(largely pigs and poultry) is more effi cient in
terms of grams of protein per unit of green-
house gas emissions than animal protein from
ruminants (cattle, sheep, and goats). However,
this simplistic comparison does not take into
account key issues such as the suitability of
land for pasture or feed production, nutritional
value beyond protein, or the use of by-products
(Garnett 2009 ). Roughly one-third of live-
stock emissions come from land use and land-
use changes.
￿ Indirect emissions from the clearing of forests
due to the encroachment of grazing into for-
ested areas as well as from the cultivation of
feed crops play an important role in the total
agricultural greenhouse gas emissions.
￿ FAO ( 2006 ) calculates that globally, livestock-
induced land-use change generates 2,400
MtCO 2 e a year, or approximately 4-5 % of
global greenhouse gas emissions.
￿ The PBL report ( 2009 ) gives a slightly differ-
ent number, attributing about 2,200 MtCO 2 e
per year to land use and livestock-induced
land-use change.
￿ If CH 4 emissions grow in direct proportion to
increases in livestock numbers, then global
livestock-related methane production is
expected to increase by 60 % by 2030.
However, changes in feeding practices and
manure management could lessen this increase
(Smith et al. 2007 ).
￿ Emissions from livestock are highest per cap-
ita in high-income countries, with estimates
ranging up to 31 % of total emissions in the
European Union. On the other hand, emis-
sions may be higher per animal in low-income
countries (Garnett 2009 ) .

3.3.3 Livestock Emissions

The livestock sector is a major contributor to
climate change, generating signifi cant emis-
sions of CO 2 , CH 4 , and N 2 O. Livestock contrib-
ute to climate change by emitting GHGs either
directly (e.g., from enteric fermentation and
manure management) or indirectly (e.g., from
feed-production activities, conversion of forest
into pasture). Based on a life cycle assessment
(LCA), it is estimated that the sector emits
about 7.1 gigatons of CO 2 e, about 18 % of the
total anthropogenic GHG emissions (FAO
2006 ).
On a global scale, the emission intensity of
meat and milk, measured by output weight,
corresponds on average to 46.2 kgCO 2 e per kg
of carcass weight (CW), 6.1 kg CO 2 e/kg CW,
and 5.4 kg CO 2 e/kg CW for beef, pork, and
chicken meat, respectively, and 2.8 kgCO 2 e/kg
of milk (FAO 2013 ). There is signifi cant vari-
ability in emissions across the different regions.
Emissions from Europe and North America
range between 1.6 and 1.9 kgCO 2 e/kg fat- and
protein-corrected milk (FPCM) at the farm
gate. The highest emissions are estimated for
sub-Saharan Africa with an average of 9.0
kgCO 2 e/kg FPCM at the farm gate. GHG emis-
sions for Latin America and the Caribbean,
Near East and North Africa, and South Asia
range between 3 and 5 kgCO 2 e/kg FPCM at the
farm gate. The global average is estimated at
2.8 kg CO 2 e (FAO 2013 ).
GHG emissions are inversely related to pro-
ductivity. At very low levels of milk production
(200 kg per cow per year), emissions were
found to be 12 kgCO 2 e/kg FPCM compared to