Shedding light on African livestock systems' greenhouse gas emissions to mitigate their environmental impact

Ruminants play a vital role in the economic and nutritional fabric of sub-Saharan Africa. However, cattle have faced criticism for their disproportionately large negative environmental impact, particularly regarding greenhouse gas emissions.

The true extent of African livestock systems’ contribution to global emissions remains poorly understood, however, primarily due to a lack of evidence-based research. At the International Livestock Research (ILRI) our research has shown that the amount of greenhouse gases emitted by smallholder livestock farms in Africa varies significantly. Surprisingly, we found that around half of the farms sampled have emission levels similar to those seen in European countries. Specifically, they measured emissions of 2.1–5.0 kilograms of CO2-equivalent per kilogram of animal product, which is comparable to the emission levels in Ireland and globally.

This means that the environmental impact of African livestock systems may not be as high as previously believed. 

A couple of years ago, the Mazingira Centre (Mazingira means ‘environment’ in Swahili) at ILRI took on the important task of improving our understanding of greenhouse gas (GHG) emissions from the livestock sector in Kenya. To achieve this, our team developed precise data collection protocols to gather activity data necessary for calculating emission factors according to the guidelines provided by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 method. These emission factors specifically focus on two sources of emissions: enteric fermentation (which occurs in the digestive systems of animals) and manure.

Using these established protocols, we collected data from three distinct regions in Western Kenya: Nyando, Nandi, and Bomet. We previously published initial estimations of emission factors for these regions, which provided insights into the variations in emissions across different livestock systems.

Painting a more complete picture of emissions

It is important to note that accurate estimation of emission factors for enteric fermentation and manure emissions alone does not provide a complete understanding of the total emissions. Other emissions associated with animal and manure-related activities, such as the production of fodder (feed) both on and off the farm, are not captured. To address this limitation and obtain a more comprehensive assessment of greenhouse gas emissions in smallholder systems, we employed a technique called ‘carbon footprinting’.

Carbon footprinting allows us to evaluate the total amount of greenhouse gases generated throughout the entire production process and express these emissions per unit of product. This measurement, known as emission intensity (EI), enables meaningful comparisons between different farm systems. In simple terms, carbon footprinting helps us understand the environmental impact of livestock farming by considering all the emissions associated with the production of livestock products, not just the emissions from enteric fermentation and manure. Our goal is to capture the variability in GHG emissions within smallholder systems and facilitate informed comparisons between them, thereby enhancing our understanding of the environmental implications of livestock farming in Kenya.

In detail, we calculated greenhouse gas (GHG) emissions from various sources on smallholder livestock farms, including enteric fermentation (emissions from the digestive systems of animals), manure management, and feed production. To measure the environmental impact, we calculated emission intensities, which means we divided the total GHG emissions produced by the farm (including all stages of production) by the total amount of milk and meat protein generated by the farm.

On average, milk contributed around 80-85% of the farm’s protein output, while meat contributed around 15-20%. Among the different sources of emissions (animal, manure, and feed production), enteric fermentation was responsible for over 95% of the farm’s emissions.

This means that efforts to reduce emissions should primarily focus on addressing enteric fermentation by exploring strategies that improve feed and animal management. By improving these aspects, farmers can increase production while reducing emissions per unit of product.

Furthermore, we found that smallholders with fewer productive animals had higher emissions per unit of product. To tackle this, implementing animal management strategies such as restructuring the herd to increase the number of productive animals on a farm could be a viable option for reducing emissions.

Our findings highlight the importance of understanding and addressing greenhouse gas emissions in smallholder livestock farms. By targeting enteric fermentation and adopting effective animal management practices, farmers can increase production while minimizing the environmental impact of their operations.

Read the study: Farm-level emission intensities of smallholder cattle (Bos indicus; B. indicus–B. taurus crosses) production systems in highlands and semi-arid regions

Story by Phyllis Ndung’u, ILRI, originally published at ILRI.org.