Reducing Emissions from Food Value Chains of Smallholders in Africa: Does the Evidence Weigh Up?
This post was written by Lini Wollenberg. Lini leads a research program on Low Emissions Agricultural Development for the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) and is a Research Associate Professor at the Rubenstein School of Environment and Natural Resources at the University of Vermont.
In December 2015, 116 countries—75 from the developing world—committed to reducing greenhouse gas emissions from agriculture in the Paris Agreement of the United National Framework Convention on Climate Change (UNFCCC). Since emissions from agriculture normally increase with production, how can agriculture effectively decrease emissions while increasing food production by 60% to meet the food demands of 9 billion people in 2050?
Feed the Future agricultural officers and other participants in the Global Learning and Evidence Exchange (GLEE) meeting in Lusaka, Zambia on March 13-16 sought to answer this question in a session on low emissions development (LED) in agriculture. LED is the practice of enhancing agriculture in ways that reduce emissions relative to future business as usual emissions and contribute to food security. In agriculture, improving the efficiency of agricultural inputs and increasing carbon sequestration in soil or biomass make it possible to reduce emissions while often increasing yields, ensuring that future emissions are lower than they otherwise would be.
Promising LED opportunities exist in livestock management, rice production, crops that rely on nitrogen fertilizers, reducing energy use and waste in supply chains, and increasing carbon sequestration in the soil or trees. Many LED practices are already considered best management practices for the productivity they provide and are consistent with existing USAID programs:
- Livestock intensification can reduce methane emissions intensities by up to 20 times for beef and 300 times for dairy. This has considerable impact, since livestock emissions are the largest source of emissions in many countries. Improving the digestibility of ruminant’s feed or decreasing the number of ruminant animals in the herd are the main avenues for reducing emissions/product. See FAO’s Tackling Climate Change through Livestock, Herrero et al. 2015 or Herrero et al. 2013 for more information.
- Reducing flooding in irrigated rice can reduce methane emissions by up to 38% without compromising yields using short duration rice or alternate wetting and drying (AWD). AWD is the practice of systematically allowing a paddy field to dry 15 cm below the soil surface during plant growth before repeating flooding. AWD can reduce water needs by 30 to 40%—an attractive outcome where farmers have to pay for water or where water is scarce. AWD is being scaled up in Bangladesh and Vietnam and is widespread in China, where it has also been shown to reduce mosquito-borne diseases. For more information on LED in rice, see the CCAC information kiosk.
- Increasing nitrogen fertilizer efficiency in crops through microdosing and strategic application timing can double emissions’ efficiencies. A review found that increasing nitrogen-use efficiency from 19 to 75% decreased the nitrous oxide emissions intensity of crop production by 56% (Groenigen et al. n.d).
- Increasing supply chain efficiency through reduced use of fossil fuel energy and reduced losses in processing and transport in agricultural value chains can help decrease carbon dioxide, nitrous oxide and methane emissions. See this analysis of nitrous oxide in supply chains.
- Increasing carbon sequestration includes avoiding conversion of high carbon landscapes, reducing burning, and increasing soil organic matter and vegetation biomass. Carbon sequestration will offset emissions and result in real, although potentially impermanent, reductions in emissions.
To better understand the evidence for LED, CCAFS modeled Feed the Future projects’ emissions using FAO’s EX-ACT tool. We found that most Feed the Future projects would reduce emissions intensity in the supply chain when modeled over a 20-year period. For example, the Resilience and Economic Growth in Arid Lands-Accelerated Growth (REGAL) activity in Kenya would reduce ruminant emissions intensities by 33-40% over 20 years by reducing the number of animals by 10% and improving feed slightly. The Agricultural Development and Value Chain Enhancement Project II (ADVANCE II) in Ghana will reduce emissions intensities of cereals (maize, soybean and irrigated rice) by 66-267% through a combination of increased yields, value chain efficiencies, reduced burning and AWD. And the Better Life Alliance activity in Zambia will reduce emissions intensities for maize by 213%, largely by preventing shrub land burning. Further analysis of the economic and social constraints to scaling up practices is needed to better understand these potentials. Also, as a modeling exercise, there are inherent uncertainties (mostly about 30-50%) to the estimated mitigation impacts.
The analysis suggests that existing agricultural development projects already will accomplish quite a bit of mitigation. Yet in most projects, even more could be done to further reduce emissions intensities, such as improving feed quality and breeds in livestock, increasing nitrogen use efficiency in crops, or avoiding burning.
To support countries’ UNFCCC ambitions, a first step is to identify and communicate existing interventions’ impacts on reducing emissions. The next—and very exciting—step is to explore what more can be done, including:
- Further reduce emissions relative to yields
- Seek absolute reductions to meet climate targets, including through carbon sequestration
- Assess and improve the economic and social feasibility of implementing practices at scale
- Prioritize practices applicable at large scales
Every economic sector, including agriculture, will have to do its share to reduce emissions if we are to meet global climate goals. Many of the principles for reducing emissions in climate are clear, so the question now is how to do it, while also improving estimates of the impacts to better track emissions benefits. Can agricultural development make a difference in this way? So far, the evidence suggests that the answer is yes.
General information on emissions in agriculture
- IPCC Fourth and Fifth Assessment Reports
- IPCC Good Practice Guidance
- CCAFS Low Emissions Agriculture website
- Climate-smart agriculture practices and technologies
- Mitigation Options Tool to identify and prioritize mitigation options
- FAOSTAT Emissions Database for quick access to emissions by source, country and year
- FAO MICCA website
- Strategies for Mitigating Climate Change in Agriculture
- Tackling Climate Change Through Livestock (Gerber et al. 2014)
- Quantifying emissions (CCAFS SAMPLES website)
- Identifying secure and low carbon food production practices: a case study in Kenya and Ethiopia (Bellarby et al. 2014)
- Does conservation agriculture deliver climate change mitigation through soil carbon sequestration in tropical agro-ecosystems? (Powlson et al. 2016)
- Limited potential of no-till agriculture for climate change mitigation (Powlson et al. 2014)
- Current and future nitrous oxide emissions from African agriculture (Hickman et al. 2011)
- Science to support climate smart agricultural development (East Africa) (Rosenstock et al. 2014)