The future for coffee production looks bleak, writes Alessandro Craparo, an International Institute of Tropical Agriculture (IITA) Research Fellow at University of the Witwatersrand in an article in The Conversation. That is, “unless climate change can be mitigated, or farmers can find ways to adapt.”
While it has been known for some time that coffee is a climate-sensitive crop - constrained by heat and drought stress - a new study shows that steadily increasing night-time temperatures are actually having the greatest impact.
“The crop is comfortable in a marginal temperature bracket ranging between 18 to 21°C. Outside of this temperature bracket the plant’s metabolic processes begin to change. This subsequently has a negative impact on yield and quality,” says the article.
The study was conducted in Tanzania where the Coffea Arabica variety is grown primarily by smallholders, and intercropped with other subsistence crops like beans, maize and bananas. Coffee is Tanzania’s most important export crop.
The study estimates annual yield losses of approximately 137 kg per hectare for every 1°C rise in minimum temperature. This is around 60 per cent of the average smallholder farmer’s current production in Tanzania. Already, yields are 50 per cent lower than they were in 1960.
Moving coffee production to higher altitudes where it is cooler is “rarely feasible,” as these areas are already populated and most contain protected forests. Adaptation strategies are needed that enable farmers to continue growing coffee.
One possible solution is shade-grown coffee which is produced in agroforestry systems. Trees grown alongside coffee reduce temperatures and provide farmers with diversity to manage risks. These systems also benefit ecosystems and biodiversity.
The article stresses the importance of choosing the right type of shade, i.e. trees that “provide a high enough canopy to help reduce the daytime maximum temperatures while allowing the night-time terrestrial radiation to escape back through the atmosphere”.
The research is part of the CGIAR program on Climate Change Agriculture and Food Security (CCAFS).
Read the full story: Coffee lovers beware: climate change may affect your brew
Download the article: Craparo ACW et al. (2015). Coffea arabica yields decline in Tanzania due to climate change: Global implications. Agricultural and Forest Meteorology 207, pp 1-10.
