- Achieving net reductions in greenhouse gas (GHG) emissions from agriculture will depend in large part on reducing consumption (and associated food waste), particularly of high GHG foods and among current high-consumption social groups. Increases in GHG efficiencies of food alone are unlikely to bring about targets for emissions reductions (Garnett 2011).
- Emissions released during the production and use of synthetic fertilizer can be reduced by: (1) recovering methane during coal mining; (2) enhancing energy efficiency in the manufacturing process; and (3), minimizing nitrogen overuse in crop production. Improving all these aspects could reduce nitrogen-fertilizer-related emissions by 20%–63% in China, which would reduce China’s total GHG emissions by 2%–6% (Zhang et al. 2012).
- Agricultural practices that are carbon-intensive include ploughing, irrigation and the use fertilizers and pesticides. Conversion to no-till systems, using integrated nutrient management and integrated pest management practices and enhancing water-use efficiency by adopting drip irrigation and sub-irrigation practices can reduce carbon emissions while simultaneously increasing soil carbon contents (Lal 2004).
- Pesticide manufacturing accounts for about 3% of the 100-year global warming potential from crops, mainly because of the energy used in the production process (Audsley et al. 2009). Emissions per hectare can be reduced by adopting cropping systems that rely less on pesticides and other inputs - and therefore, the GHG cost of their production (Paustian et al. 2004, cited by Smith et al. 2007).
- In high-income countries, emissions resulting from activities beyond the farm gate account for about half of food-chain emissions and are fairly evenly distributed between the different stages, but the situation in developing countries has not yet been adequately studied (Garnett 2011).
- Measures to reduce refrigeration emissions include energy efficiency, the correct specification of new equipment, novel technologies such as trigeneration, action to eliminate refrigerant leakage and the use of alternatives to hydrofluorocarbons (Garnett 2011).
- In other areas of retail and manufacturing energy use, mitigation measures include energy management, low-carbon building design and the use of combined heat and power, wind, solar and biomass. The carbon intensity of fuel inputs can be reduced by improving energy efficiency and using alternative fuels such as biomass, biogas, wind and solar power (Garnett 2011).
- For transport, mitigation options include modal shift to less GHG-intensive modes of transport, investment in more efficient vehicles, driver training and the use of information and communications technology for optimal route planning, vehicle sharing and backhauling (Garnett 2011).
- Packaging measures include bulk importing; more recently there have been moves towards a more life-cycle based approach to assessing the merits of packaging materials (Garnett 2011).
- Demand-side measures in food systems, such as reductions in food waste or in consumption of livestock products, could offer a mitigation potential of 1.5 - 15.6 Gt CO2eq per year at carbon prices ranging from 20 to 100 USD per tonne, compared to supply side measures that offer 1.5 to 4.3 Gt. Demand-side measures are likely to improve food security, but may face challenges in governance and collective action (Smith et al. 2013).
Pre- and post-retail mitigation
|Public investment in transport infrastructure has the potential to reduce spoilage.
||With higher food prices in developed countries, it is likely that there would be a decrease in the volume of waste produced by consumers.
|Better-functioning markets and the availability of capital can increase food-chain efficiency (e.g. by creating opportunities for cold-storage).
||Alerting consumers about the scale of the problem and providing them strategies for reducing food loss may reduce losses.
|Education and extension services can contribute to spreading existing technologies and best practices.
||Advocacy, education and possibly legislation may also reduce waste in the food service and retail sectors.
|Market and finance mechanisms can protect farmers from having to sell at peak supply, leading to surpluses and wastage.
||Legislation such as that on sell-by dates and swill that has inadvertently increased food waste should be re-examined within a more inclusive competing-risks framework.
|Small-scale food storage can benefit smallholder farmers and reduce waste at this level.
|Source: Godfray et al. (2010).
Sources and further reading
- Audsley E, Stacey K, Parsons DJ, Williams AG. 2009. Estimation of the greenhouse gas emissions from agricultural pesticide manufacture and use. Cranfield, UK: Cranfield University. (Available from http://dspace.lib.cranfield.ac.uk/handle/1826/3913)
- Garnett, T. 2011. What are the best opportunities for reducing greenhouse gas emissions in the food system (including the food chain)? Food Policy Volume 36, Supplement 1, pages S23-S32 (Available from http://dx.doi.org/10.1016/j.foodpol.2010.10.010)
- Godfray HCJ, Beddington JR, Crute IR, Haddad L, Lawrence D, Muir JF, Pretty J, Robinson S, Thomas SM, and Toulmin C. 2010. Food security: the challenge of feeding 9 billion people. Science 327(5967):812-818. DOI:10.1126/science.1185383.
- Lal R. 2004. Carbon emission from farm operations. Environment International 30:981–990. (Available from http://dx.doi.org/10.1016/j.envint.2004.03.005)
- Paustian K, Babcock BA, Hatfield J, Lal R, McCarl BA, McLaughlin S, Mosier A, Rice C, Robertson GP, Rosenberg NJ, Rosenzweig C, Schlesinger WH, Zilberman D. 2004. Agricultural mitigation of greenhouse gases: science and policy options. (Available from http://www.netl.doe.gov/publications/proceedings/01/carbon_seq/4C2.pdf) (Accessed on 7 November 2013)
- Smith P, Haberl H, Popp A, Erb K, Lauk C, Harper R, Tubiello F de Siqueira P, A Jafari M, Sohi S, Masera O, Böttcher H, Berndes G, Bustamante M, Ahammad H, Clark H, Dong H, Elsiddig E, A Mbow C, Ravindranath N, H Rice C, W Robledo-Abad C, Romanovskaya A, Sperling F, Herrero M, House I, Rose S. 2013. How much land based greenhouse gas mitigation can be achieved without compromising food security and environmental goals? Global Change Biology 19(8): 2285-2302. http://dx.doi.org/10.1111/gcb.12160
- Smith P, Martino D, Cai Z, Gwary D, Janzen H, Kumar P, McCarl B, Ogle S, O’Mara F, Rice C, Scholes B, Sirotenko O. 2007. Agriculture. In: Metz B, Davidson OR, Bosch PR, Dave R, Meyer LA, eds. Climate change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. (Available from http://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-chapter8.pdf) (Accessed on 5 November 2013)
- Zhang W-F, Dou Z-X, He P, Ju X-T, Powlson D, Chadwick D, Norse D, Lu Y-L, Zhang Y, Wu L, Chen XP, Cassman KG, Zhang F-S. 2012. New technologies reduce greenhouse gas emissions from nitrogenous fertilizer in China. PNAS 110(21):8375–8380. (Available from http://www.pnas.org/content/110/21/8375) (Accessed on 7 November 2013)