Evaluation of Greenhouse Gas Emissions along the Small-Holder Coffee Supply Chain in Kenya

Abstract

Coffee plays an important role in sustaining millions of livelihoods around the world. The production of Arabica coffee is greatly affected by the changing climate. Besides suffering from changing climate, coffee is also a contributor to climate change as a result of greenhouse gases emitted throughout the supply chain. The coffee sector is therefore interested in climate-friendly coffee production methods. Understanding greenhouse gas emissions from the coffee supply chains is important for evaluating options for climate change mitigation within the sector. In this study, data from 108 small scale farmers affiliated to three wet mills in Kenya was used to calculate the carbon footprint of coffee parchment, and identify emission hotspots within different farmer production levels. The results indicate that farmer production level had a highly significant negative impact on carbon footprint (p<0.0001). The carbon footprint decreased with increase in production level. The mean farm level carbon footprints for 1kg of fresh coffee cherries were 0.05 kg CO2e, 0.24 kgCO2e and 0.54 kgCO2e for high, medium and low producers respectively. The main GHG emission hotspot at farm level across all the levels of production was the inputs of organic and inorganic nitrogen (94%). The mean carbon footprint at processing for 1kg coffee parchment was 2.6 kgCO2e. At the wet mills the major emission hotspot was the processing wastewater (97%). Mitigation practices proposed therefore focused on the reduction of emissions from fertiliser use and wastewater treatment.