The document discusses the role of agriculture, forestry, and other land use (AFOLU) in climate change mitigation, highlighting its significant contributions to greenhouse gas emissions and potential mitigation strategies. Key emissions sources include enteric fermentation, manure, and synthetic fertilizers, with agriculture accounting for about a quarter of anthropogenic emissions. The analysis suggests that dietary changes and improved land management practices can substantially reduce emissions, emphasizing the critical interplay between population growth, dietary habits, and environmental impact.

1. Climate Change Mitigation in
Agriculture and Forestry
(IPCC WGIII AR5 Chapter 11)
Cassia Moraes – MPA in Development Practice at Columbia University

2. Introduction
- Agriculture, Forestry, and Other Land Use (AFOLU)
plays a central role for food security and sustainable
development.
- Plants take up CO2 from the atmosphere and N from
the soil, re‐distributing it among different pools. CO2
and other GHG - largely methane (CH4) and nitrous
oxide (N2O) - are in turn released to the atmosphere by
plant respiration, by decomposition, and by combustion.
- AFOLU activities lead to both sources of CO2 and other
GHG emissions, and sinks of CO2.

5. TOP 3 GHG Emissions from Agriculture
1) Enteric Fermentation: Global emissions grew from
1.4 to 2.1 GtCO2eq/yr between 1961 and 2010 – annual
grow of 0.70% (75% of the total emissions coming from
developing countries).
2) Manure: Global emissions from manure (organic
fertilizer manure deposited on pasture) grew between
1961 and 2010 from 0.57 to 0.99 GtCO2eq/yr - annual
grow of 1.1%.
3) Synthetic Fertilizer: Emissions from synthetic
fertilizers grew from 0.07 to 0.68 GtCO2eq/yr at an
average rate of 3.9%/yr from 1961 to 2010.

6. GHG fluxes from forestry and other land use
- AFOLU accounted for about a third of anthropogenic
CO2 emissions from 1750 to 2011 and 12% of emissions
in 2000 to 2009.
- Model results indicate AFOLU emissions peaked in the
1980s in Asia and LAM regions and declined thereafter.
This is consistent with a reduced rate of deforestation,
most notably in Brazil, and some areas of afforestation.
- Burning vegetation releases CO2, CH4, N2O,
ozone‐precursors and aerosols to the atmosphere.
When vegetation regrows after a fire, it takes up
CO2 and nitrogen.

7. Current Scenario
- AFOLU is responsible for about a quarter of
anthropogenic GHG emissions (deforestation,
livestock’s emissions, soil and nutrient management).
- Unique scenario for mitigation options:
• Increase removals of GHG (forestry);
• Reduction of emissions (livestock and land use).
- Critical factors that impact this sector: population
(growth), economic and technological developments,
changes in behaviour over time, and how these
translate into demand for food, fuel and other products.

8. - Mitigation include supply‐side and demand‐side
options:
1) Supply-side: increasing production without
increasing emissions (e.g. sustainable intensification).
(i) reducing emissions from land‐use change, land and
livestock management;
(ii) reducing deforestation;
(iii) increasing terrestrial carbon stocks (sequestration
in soils and biomass).
(iv) reductions of direct (e.g., agricultural machinery,
pumps, fishing craft) or indirect (e.g., production of
fertilizers) energy-related emissions.

9. 2) Demand-side: agricultural CH4 and N2O would
triple by 2055 to 15.3 GtCO2eq/yr if current dietary
trends and population growth were to continue.
 The potential to reduce GHG emissions through
changes in consumption was found to be higher than
that of technical mitigation measures.
(i) reducing losses and wastes of food in the supply
chain and during consumption (30─40% of all
food produced is lost);
(ii) changing diets towards less GHG‐intensive food
(animal products vs plant‐based options) ;
(iii) reduction of overconsumption in regions where
this is prevalent.

10. - Land‐use change can affect GHG balances, albedo
and other climate drivers (uncertain outcomes).
- Bioenergy could play a critical role for climate
change mitigation, if deforestation is avoided and
best‐practice land management is implemented.
- Any large‐scale change in land use (e.g. bioenergy
and carbon sequestration) will likely increase the
competition for land, water, and other resources,
and conflicts may arise.
- Policies in agriculture and forest management need
to account for both mitigation and adaptation.

11. “The following changes were evaluated: no ruminant
meat, no meat, and a diet without any animal products.
Changed diets resulted in GHG emission savings of
34─64% compared to the ‘business‐as‐usual’ scenario;
a switch to a ‘healthy diet’ recommended by the
Harvard Medical School would save 4.3 GtCO2eq/yr
(‐36%). Adoption of the ‘healthy diet’ (which includes a
meat, fish and egg consumption of 90 g/cap/day)
would reduce global GHG abatement costs to reach a
450 ppm CO2eq concentration target by ~50%
compared to the reference case (Stehfest et al., 2009).
The analysis assumed nutritionally sufficient diets;
Reduced supply of animal protein was compensated by
plant products (soy, pulses, etc.).”
(IPCC WGIII AR5 Chapter 11 p.38)

12. Resources:
- IPCC Working Group III AR5 Chapter 11 -
Agriculture, Forestry and Other Land Use (AFOLU):
http://report.mitigation2014.org/drafts/final-draft-
postplenary/ipcc_wg3_ar5_final-
draft_postplenary_chapter11.pdf