Trends of GHG emissions resulting from food systems (crops,
livestock, land-based aquaculture, processed food)
Louis Verchot
IPCC-FAO EXPERT MEETING ON CLIMATE CHANGE, LAND USE, AND FOOD SECURITY
23-25 January 2017, FAO Headquarters, Rome

Historical cumulative emissions by source
Land-use change represents about 26% of cumulative emissions over 1870–2015,
coal 35%, oil 26%, gas 10%, and others 3%
Others: Emissions from cement production and gas flaring
Source: Global Carbon Project

Agriculture is both a source and sink of
greenhouse gases (GHGs)
Emissions:
• Energy (including fertilizer production) 0.4 – 0.6 Gt CO2
• Non-CO2 GHG 5.2 – 6.3 Gt CO2e
• Deforestation (gross) 8.6 – 10.3 Gt CO2
Sinks
• Crop and livestock management
• Agroforestry

Four different datasets tell a similar relative
story about major agricultural emissions
Source: AR5

Data: USEPA 2006 data projected through 2030
Emissions are highest in developing countries
and will grow significantly by 2030
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Sub-Saharan Africa
1990 2000 2010 2020 2030
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W. Europe
E. Europe
N2O Agricultural soils
N2O Manure management
CH4 Enteric fermentation
CH4 Manure management
CH4 Other agricultural
CH4 Rice cultivation

Contribution of the leading emission sources in
percent of total emissions per pixel
2000–2005.
Source: Roman-Cuesta et al. (2016)

High rates of Fertilizer N application are found
in Mid-west US, W. Europe, and E and S Asia
Source: Potter et al. (2010)

A new twist to our story: Soils are losing carbon
across the northern part of the globe
Source: Crowther et al., (2016)
Map of predicted changes in soil C stocks due to a 1oC rise in temperature
by 2050 under a ‘no acclimatization’ scenario.

Depending on the amount of time for the full effect of
warming to be felt, the losses could be considerable
Source: Crowther et al., (2016)

Meat consumption will drive increased GHG
emissions
Economic
trends
• Global livestock population – 17 billion animals
• Meat consumption has almost tripled in the last four decades and
has increased by over 30% in the last ten years.
• Dairy consumption is up by over 70 percent in the last four decades.
• Greatest consumption increases are seen in East and Southeast Asia
(>3% y-1 through 2020)

Meat consumption will drive increased GHG
emissions
Economic
trends
• Livestock production concentrates in areas with cheap input supplies
and good market outlets (e.g. in the vicinity of large cities).
• More specialized and intensive industrial production systems.
• Production is shifting from ruminants to monogastrics, that have a
better feed conversion ratio.
• Vertical integration along the land–livestock–food chain creates
economies of scope.

Globally, increases in production monogastrics
greatly exceeds that of ruminants
Source: Chemnitz et al. (2014)

Monogastrics produce much less GHG
than ruminants
Source : Carlsson Kanyama and González (2009)
Calculation based on IPCC Tier 1 factors

119 INDC submissions pledge agricultural GHG reductions

Some of the highest emissions per haOrganic
soils
• 25 million ha have been drained for agriculture (~7% of the area).
• 60 percent is in boreal and cool temperate regions;
• 5 percent is in warm temperate regions; and
• 34% is in the tropics, mostly in Southeast Asia.
• Emissions from these are almost one billion tonnes CO2eq
annually (~85% CO2; ~15% N2O).
• Fire and fertilization of these soils create more emissions.

Tropical peatlands are much more
extensive than previously thought
1.7 M km2 tropical peatlands
Source: Gumbricht et al. (in press)

A growing emissions sourceAquaculture
• Production of fish and shellfish in aquaculture > 55
Mt (~half global fish consumption).
• This production has high N2Oemissions, which are
predicted to increase to about 6% of anthropogenic
N2O emissions by 2030.

Shrimp culture = 38% of global mangrove loss;
Other aquaculture = 14%.
Donato et al. Nature Geoscience (2011)

LCA of the food system of the UK: food processing and
packaging make up about 20% of GHG emissions
Source: Garnett et al (2011)

Thank You