E-3 - Agriculture, Forestry, and Other Land Use

Total Sector Emissions

In 2019 the IPCC published Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable landmanagement, food security, and greenhouse gas fluxes in terrestrial ecosystems - also known as IPCC SRCCL.

The IPCC (IPCC SRCCL 2019)¹ gives us the following breakdown of average emissions within AFOLU during the period 2007-2016:

• Total world emissions: $52.0\pm 4.5$ $GtC{O}_{2}eq$ $y{r}^{–1}$
  • Total AFOLU emissions: $12.0\pm 2.9$ $GtC{O}_{2}eq$ $y{r}^{–1}$ (=23% of total GHG emissions)
    • Agriculture: $6.2\pm 1.4$ $GtC{O}_{2}eq$ $y{r}^{–1}$
    • FOLU: $5.8\pm 2.6$ $GtC{O}_{2}eq$ $y{r}^{–1}$
      • LUC for food system: $4.9\pm 2.5$ $GtC{O}_{2}eq$ $y{r}^{–1}$

The food sector appears to be the only significant emission source within AFOLU if the “global food system” approach is adopted. Key figures from (IPCC SRCCL 2019)¹:

• Emissions within farm gate and from agricultural land expansion contributing to the global food system represent 16–27% of total anthropogenic emissions (medium confidence).
• Emissions outside the farm gate represent 5–10% of total anthropogenic emissions (medium confidence).
• Total GHG emissions from agriculture [increase] to $11.1\pm 2.9$ $GtC{O}_{2}eq$ $y{r}^{–1}$ when including relevant land use. Without intervention, these are likely to increase by about 30–40% by 2050, due to increasing demand based on population and income growth and dietary change (high confidence).
• Total technical mitigation potential of dietary changes is estimated as $0.7\pm 8.0$ $GtC{O}_{2}eq$ $y{r}^{–1}$ by 2050 (medium confidence).

From this we can draw the conclusion that 2050 estimates are 35% higher than 2019, thus the projection is:

• Total AFOLU: $16.2$ $GtC{O}_{2}eq$ $y{r}^{–1}$
  • Agriculture: $8.4$ $GtC{O}_{2}eq$ $y{r}^{–1}$
  • FOLU: $7.8$ $GtC{O}_{2}eq$ $y{r}^{–1}$
    • LUC for food system: $6.6$ $GtC{O}_{2}eq$ $y{r}^{–1}$

Furthermore, that the “maximum” potential mitigation from dietary changes (demand-side) is:

• $8.0$ $GtC{O}_{2}eq$ $y{r}^{–1}$
  • Out of $15.0$ $GtC{O}_{2}eq$ $y{r}^{–1}$
    • I.e. 53% of food system emissions 2050 have mitigation measures outlined in IPCC 2019

Emission Breakdown

Agriculture emission breakdown into sub-sectors is diffuse in all IPCC material. Our best guess is a harmonisation of (IPCC SRCCL 2019)¹, (Hiraishi et al. 2014)² and (FAO 2023)³ reports. The following hierarchy is ordered roughly from largest source of emission to smallest per sub-sector:

• A-3A - Livestock
  • E-3A1 - Enteric Fermentation
    • E-3A1a - Cattle
    • E-3A1b - Buffalo
    • E-3A1c - Sheep
    • E-3A1d - Goats
    • E-3A1e - Camels
    • E-3A1f - Horses
    • E-3A1g - Mules and Asses
    • E-3A1h - Swine
    • E-3A1j - Other Livestock
  • E-3A2 - Manure Management
    • E-3A2a - Cattle
    • E-3A2b - Buffalo
    • E-3A2c - Sheep
    • E-3A2d - Goats
    • E-3A2e - Camels
    • E-3A2f - Horses
    • E-3A2g - Mules and Asses
    • E-3A2h - Swine
    • E-3A2i - Poultry
    • E-3A2j - Other Livestock
• E-3B - Land
  • E-3B1 - Forest Land
  • E-3B2 - Cropland
  • E-3B3 - Grassland
  • E-3B4 - Wetlands
  • E-3B5 - Settlements
  • E-3B6 - Other Land
• E-3C - Aggregate Sources and Non-CO₂ Emissions Sources on Land
  • E-3C1 - GHG Emissions from Biomass Burning
  • E-3C2 - Liming
  • E-3C3 - Urea Application
  • E-3C4 - Direct N2O Emissions from Managed Soils
  • E-3C5 - Indirect N2O Emissions from Managed Soils
  • E-3C6 - Indirect N2O Emissions from Manure Management
  • E-3C7 - Rice Cultivations
  • E-3C8 - CH4 from Drained Organic Soils
  • E-3C9 -CH4 from Drainage Ditches on Organic Soiils
  • E-3C10 - CH4 from Rewetting of Organic Soils
  • E-3C11 - CH4 Emissions from Rewetting of Mangroves and Tidal Marshes
  • E-3C12 - N2O Emissions from Aquaculture
  • E-3C13 - CH4 Emissions from Rewetted and Created Wetlands on Inland Wetland Mineral Soils
  • E-3C14 - Other
• E-3D - Other
  • E-3D1 - Harvested Wood Products
  • E-3D2 - Other

Mitigation Potential

See M-3 - AFOLU as well as M-6 - Waste.

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1. IPCC SRCCL. 2019. Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Landmanagement, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems. Intergovernmental Panel on Climate Change (IPCC). https://doi.org/10.1017/9781009157988. ↩↩↩

2. Hiraishi, T, T Krug, K Tanabe, N Srivastava, J Baasansuren, M Fukuda, and T. G. Troxler, eds. 2014. 2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands. IPCC. http://www.ipcc-nggip.iges.or.jp/public/wetlands/. ↩

3. FAO. 2023. Agrifood Systems and Land-Related Emissions: Global, Regional and Country Trends, 2001–2021. FAOSTAT Analytical Briefs, No. 73. FAO. https://doi.org/10.4060/cc8543en. ↩