Agriculture as a Source of GHGs - Climate Resilient Agriculture for Ensuring Food Security - page 37

3.3.4 Direct Agricultural Emissions

countries was responsible for 74 % of total agri-
cultural emissions.
In seven of the ten regions, N 2 O from soils
was the main source of GHGs in the agricultural
sector in 2005, mainly associated with N fertiliz-
ers and manure applied to soils. In the other three
regions - Latin America and the Caribbean; the
countries of Eastern Europe, the Caucasus, and
Central Asia; and OECD Pacifi c - CH 4 from
enteric fermentation was the dominant source
(US-EPA 2006a ). This is due to the large live-
stock population in these three regions which, in
2004, had a combined stock of cattle and sheep
equivalent to 36 % and 24 % of world totals,
respectively (FAO 2003 ).

Non-CO 2 agricultural emissions are about 6,100
MtCO 2 e per year - about 11 % of total global
greenhouse gas emissions and 56 % of global
non-CO 2 greenhouse gas emissions (US-EPA
2011 ).
￿ Non-CO 2 agricultural emissions are primarily
N 2 O from soil management, including the
application of inorganic and organic fertiliz-
ers, and methane (CH 4 ) from rice production
and farm animal digestion.
￿ Agriculture's responsibility for non-CO 2
greenhouse gas emissions is expected to grow
about 20 % by 2030, reaching 7,313 MtCO 2 e
per year.
With an estimated global emission of non-CO 2
GHGs from agriculture between 5,120 MtCO 2 e/
year (Denman et al. 2007 ) and 6,116 MtCO 2 e/
year (US-EPA 2006a ) in 2005, agriculture
accounts for 10-12 % of total global anthropo-
genic emissions of GHGs. Agriculture contrib-
utes about 47 % and 58 % of total anthropogenic
emissions of CH 4 and N 2 O, respectively, with a
wide range of uncertainty in the estimates of both
the agricultural contribution and the anthropo-
genic total. N 2 O emissions from soils and CH 4
from enteric fermentation constitute the largest
sources, 38 % and 32 % of total non-CO 2 emis-
sions from agriculture in 2005, respectively
(US-EPA 2006a ). Biomass burning (12 %), rice
production (11 %), and manure management
(7 %) account for the rest. CO 2 emissions from
agricultural soils are not normally estimated sep-
arately, but are included in the land use, land-use
change, and forestry sector (e.g., in national
GHG inventories) (Fig. 3.4 ) . So there are few
comparable estimates of emissions of this gas in
agriculture. Agricultural lands generate very
large CO 2 fl uxes both to and from the atmosphere
(IPCC 2001 ), but the net fl ux is small. US-EPA
( 2006b ) estimated a net CO 2 emission of 40
MtCO 2 e from agricultural soils in 2000, less than
1 % of global anthropogenic CO 2 emissions.
Both the magnitude of the emissions and the
relative importance of the different sources vary
widely among world regions. In 2005, the group
of fi ve regions mostly consisting of Non-Annex I

3.3.5 Trends Since 1990

Globally, agricultural CH 4 and N 2 O emissions
increased by 17 % from 1990 to 2005, an average
annual emission increase of 58 MtCO2e/year
(US-EPA 2006a ). Both gases had about the same
share of this increase. Three sources together
explained 88 % of the increase: biomass burning
(N 2 O and CH 4 ), enteric fermentation (CH 4 ), and
soil N 2 O emissions (US-EPA 2006a ).
During that period, according to US-EPA
( 2006a ), the fi ve regions composed of Non-
Annex I countries showed a 32 % increase in
non-CO 2 emissions (equivalent to 73 MtCO 2 e/
year). The other fi ve regions, with mostly Annex
I countries, collectively showed a decrease of
12 % (equivalent to 15 MtCO 2 e/year) (Fig. 3.4 ).
This was mostly due to non-climate macroeco-
nomic policies in the Central and Eastern
European and the countries of Eastern Europe,
the Caucasus, and Central Asia.

3.3.6 Future Global Trends

Agricultural N 2 O emissions are projected to
increase by 35-60 % up to 2030 due to increased
nitrogen fertilizer use and increased animal
manure production (FAO 2003 ). Similarly,
US-EPA ( 2006a ) (Fig. 3.4 ) estimated that N 2 O
emissions will increase by about 50 % by 2020