COFFEE

Coffea arabica is native to Southwestern Ethiopia and is a naturally occurring, understory shrub. It is a critically important crop for household incomes, contributing US$ 750 million to the country's foreign exchange. The species is highly sensitive to changes in temperature, rainfall and humidity, and therefore vulnerable to climatic extremes. Increases in temperature are known to decrease flowering and fruiting as well as increase the incidence of pests1. Changes in timing of rainfall can impact flowering events, particularly during the months of January to March when peak pollination occurs. It prefers temperature and humidity conditions at higher elevations; therefore, its distribution has been projected to decline by 38-90% as a result of climate change over this century2. Production of Ethiopian coffee involves relatively minimal management and little to no chemical inputs (e.g. fertilizers and pesticides/herbicides). The largest influence to yields would be due to shade management, whereby reducing the number of canopy trees increases solar radiation to coffee shrubs and by extension berry production.

1Ovalle-Rivera O, Läderach P, Bunn C, Obersteiner M, Schroth G (2015) Projected Shifts in Coffea arabica Suitability among Major Global Producing Regions Due to Climate Change. PLoS ONE 10(4): e0124155. doi:10.1371/journal. pone.0124155
2Davis, A.P., T.W. Gole, S. Baena and J. Moat (2012) The Impact of Climate Change on Indigenous Arabica Coffee (Coffea arabica): Prediction Future Trends and Identifying Priorities. PLoS ONE 7(11): e47981

COCOA

 Unlike C. arabica, Theobroma cacao is not native to Ghana but originates in Central America. The crop was first established in Ghana in the 1870s by a Ghanaian misisonary, Tetteh Quarshie. Plantations were first established in Ghana's Eastern Region, but have progressively traveled westward across the country over the last century as older farms suffered lowered yields. The previous model for plantation establishment had been clearance of forest areas to maximize soil fertility, followed by planting of young cocoa trees and subsistence crops such as banana, plantain and cocoyam. Remnant forest trees were often allowed to remain in farms to help with shading the young cocoa trees; however, as the cocoa becomes more mature it is considered preferable to have low shade cultivation. Cocoa is an extremely important crop nationally, contributing US$ 2 billion in foreign exchange. With Cote d'Ivoire, Ghana produces 53% of global cocoa beans, virtually all of it through smallholder agriculture. However, of all cocoa growing regions, Ghana has the lowest annual precipitation and has exhibited a long-term drying trend since 19703. Over the last several decades there has been a steady move to more intensively-managed, low shade cocoa cultivation. With low shade/high radiation conditions, cocoa requires more nutrient inputs4 and exhibits greater extremes in diurnal temperature and vapour pressure deficits.

3Fauset, S, T.R. Baker, S.L. Lewis, T.R. Feldpausch, K. Affum-Baffoe, E.G. Foli, K.C. Hamer and M.D. Swaine (2012) Drought-induced shifts in the floristic and functional composition of tropical forests in Ghana. Ecology Letters 15(10):1120-1129
4G.A.R. Wood and R.A. Lass (2001) Cocoa, 4th Edition  Blackwell Science, Oxford, UK