Course 5: Reduce Greenhouse Gas Emissions from Agricultural Production (Synthesis)
Agricultural production emissions arise from livestock farming, application of nitrogen fertilizers, rice cultivation, and energy use. These production processes are traditionally regarded as hard to control. In general, our estimates of mitigation potential in this course are more optimistic than others’, partly because many analyses have not fully captured the opportunities for productivity gains and partly because we factor in promising potential for technological innovations.
Even with Large Productivity Gains, We Project Production Emissions to Rise
Annual emissions from agricultural production processes (i.e., excluding emissions from land-use change) reach 9 Gt in our 2050 baseline (Figure 17), leaving a 5 Gt GHG mitigation gap relative to our target emissions level of 4 Gt. The baseline already incorporates large productivity gains, without which the gap would rise to 7 Gt. Most production emissions take the form of two trace gases with powerful warming effects, nitrous oxide and methane.
Figure 17 |
Annual agricultural production emissions reach 9 gigatons in our 2050 baseline projection
- 75Hristov et al. (2014) and Gerber et al. (2013) provide good summaries of the research results to date for all these approaches.
- 76Hristov et al. (2015); Martínez-Fernández et al. (2014); Reynolds et al. (2014); Romero-Perez et al. (2015).
- 77Data on manure management systems are rough but analysis in this paper uses estimates by FAO for the GLEAM model, provided separately but reflected in Gerber et al. (2013) and the I-GLEAM model available at http://www.fao.org/gleam/resources/en/.
- 78Data on manure management systems are rough but analysis in this paper uses estimates by FAO for the GLEAM model, provided separately but reflected in Gerber et al. (2013) and the I-GLEAM model available at http://www.fao.org/gleam/resources/en/.
- 79IPCC (2006), Table 10.17, lists different conversion factors for the percentage of the potentially methane-contributing portions of manure (volatile solids) based on different manure management systems. These percentages depend on temperatures, and the ratios between liquid and dry systems vary modestly because of that, so the ratios described above are those at an average annual temperature of 20 degrees Celsius. The lagoon liquid slurry systems chosen involve a liquid slurry without a natural crust cover, which tends to form in some liquid slurry systems, and which applies both to liquid slurry storage and pit storage below animal confinements.
- 80Authors’ estimate.
- 81USDA/ERS (2015) averages annual prices from 2010 to 2015.
- 82Doole and Paragahawewa (2011).
- 83Byrnes et al. (2017).
- 84Ward et al. (2016); Galbally et al. (2010); Barneze et al. (2014); Mazzetto et al. (2015); Pelster et al. (2016); Sordi et al. (2014).
- 85MarketsAndMarkets (2015) estimated global sales of controlled release fertilizers at $2.2 billion in 2014, out of worldwide nitrogen sales (for 2012) of $99 billion (MarketsAndMarkets ).
- 86Authors’ estimate.
- 87Su et al. (2015).
- 88Jiang et al. (2017).
- 89Joshi et al. (2013).
- 90Itoh et al. (2011).
- 91Saini (2013).
- 92CGIAR Research Program on Roots, Tubers and Bananas (2016).
- 93Goodrich et al. (2012).
- 94See, e.g., Powlson et al. (2016); Powlson et al. (2014); van Groenigen et al. (2017).
- 95Powlson et al. (2014), summarizing studies.
- 96Kirkby et al. (2011).
- 97Padhee (2018).