Surface Temperature Changes and Effects on Cocoa Yield in the Top Four Cocoa Producing Countries of Africa: A Comparative Analysis

Abstract

Cocoa is a leading export crop to the world market and Cote D’Ivoire, Ghana, Nigeria and Cameroon in Africa, accounts for about 70% of the global supply. However, increasing global warming with attendant high ambient temperature had affected yields in the tropical regions of Africa. The data of 61 years (1961 – 2021), area harvested (ha), yield (kg/ha) and temperature (OC) were sourced from the database of Food and Agricultural Organisation Corporate Statistical (FAOSTAT). Least squares regression and correlation analysis models were used for data analysis. Results showed that mean ambient temperature in Cote D’Ivoire, Ghana, Nigeria and Cameroon have increased by 0.7661, 0.7507, 0.7333 and 0.6400 OC for a total of 51, 51, 50 and 49 years respectively, while mean decreases were 0.1541, 0.1693, 0.1710, 0.1392oC for 10, 10, 11 and 12 years respectively. Annual average temperature increase was highest (0.0243oC) in Cote D’Ivoire with regression coefficient (R2) of 0.7232 and least (0.0200oC) in Nigeria at R2 of 0.6380. However, in both countries, annual temperature decreased by 0.0012o and 0.0007o with R2 of 0.0052 and 0.0014 respectively. The mean annual temperature increase in Ghana and Cameroon were 0.023o and 0.0204o with R2 of 0.7364 and 0.6965 respectively, while the decreases were 0.0019o and -0.0011o with R2 of 0.0152 and 0.0431 respectively. The cocoa cumulative yield (kg/ha) reduced by 105.8, 90.8 and 75.0kg/ha respectively in Cote D’Ivoire, Ghana and Cameroon when temperature decreased, but increased by 12.5kg/ha in Nigeria during same temperature decreasing trend. In Ghana and Cameroon, cocoa annual yield was higher in the years of temperature increase, while decreased ambient temperature enhanced cocoa yield in Nigeria and Cote D’Ivoire. Hence, to enhance cocoa yield in the top four cocoa producing countries of Africa, the ambient temperatures should be controlled through the adoption of Good Agricultural Practices (GAP).