Globally, GHG emissions from food processing and post-harvest wastes contribute significantly to climate change. According to FAO, food loss and waste accounts for about 4.4 gigatonnes of GHG emissions (4.4 Gt CO2 eq) per year. If food loss and waste were its own country, they say, it would be the world’s third-largest emitter after China and the United States. In fact, food loss and waste generate more than four times as much annual GHG emissions as aviation and is comparable to emissions from road transport.
GHGs from agricultural wastes come from various sources, including farms, electricity and heat used in processing, energy used to transport, store and cook food, decaying wastes and from land-use change and deforestation associated with producing food that is ultimately lost or wasted. Cutting waste offers promising ways to cut GHG emissions.
Nigeria is the largest producer of cassava in the world, producing some 57 million tonnes of tuberous roots a year (FAO). Cassava is a major food source and provides livelihoods for many households. Processing it also results in large amounts of waste in various forms, including solid and liquid residues that are hazardous in the environment. The most important biological wastes derived during cassava processing are cassava peels and the liquid effluent squeezed out of the fermented mash. In addition to peels, stumps and undersized or damaged tubers are discarded during processing, and together these account for up to a third of total weight of tubers processed. The peels are usually dumped on land or in water bodies and left to rot, leading to health and environmental hazards. The International Livestock Research Institute (ILRI) estimated about 14 million tonnes of cassava peels are generated in Nigeria annually. Its research suggests that these peels could be used to increase the availability of animal feed while reducing GHGs.
In 2015, CGIAR scientists developed low-tech ways to rapidly transform wet cassava peels into high-quality, safe and hygienic feed ingredients. The process is simple and can be carried out by small-scale processors, more than 80% of whom are women. This transforms cassava waste into a valuable feed resource, generates new incomes, creates jobs and improves well-being by cleaning up the environment. It also helps reduce GHG emissions around cassava processing centres.
The results of this research and testing with the private sector are now moving into application, with innovative processing technology converting fresh peels into high-quality cassava peel mash for use as livestock feed (ILRI). Cassava peels are also being transformed into biogas that can be used as an alternative energy source – reducing emissions from fossil fuels.
While climate-smart agriculture is often considered a priority for farmers and producers as they grow the food we need, we must be sure not to overlook all parts of agricultural value chains; opportunities to reduce GHG emissions can be exploited in unexpected places.
This article was created through a CTA-led process to document and share actionable knowledge on ‘what works’ for ACP agriculture. It capitalises on the insights, lessons and experiences of practitioners to inform and guide the implementation of agriculture for development projects.