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INSTITUTE FOR METEOROLOGICAL TRAINING

AND RESEARCH (IMTR), NAIROBI –KENYA

IMPACT OF CLIMATE CHANGE ON COCOA YIELD

PRODUCTION USING FORECAST MODELS

BY:

WILLIAM AGYAKWAH

SUPERVISOR:

PASCALINE CHEMAIYO

JULY, 2014

EXECUTIVE SUMMARY

Various forecast models: General Circulation Models (GCM), Simple Climate Models

(SCM), Multiple Regression Analysis and Tobit Model were used to predict the impact of

climate change on cocoa yield production. The climate change (temperature and rainfall)

scenarios for the semi-deciduous forest and evergreen rainforest zones of Ghana constructed

using process-based methods that rely on the General Circulation Models (GCM) in

conjunction with Simple Climate Models (SCM) indicated that projected mean annual

rainfall values in the semi deciduous forest zone of Ghana will decline by -2.8, -10.9 and -

18.6% in year 2020, 2050 and 2080 respectively. In the evergreen rainforest forest zone,

mean annual rainfall will also decline by -3.1, -12.1 and -20.2% respectively. Mean annual

temperature changes will rise by 0.8, 2.5 and 5.4 and 0.6, 2.0 and 3.9oC respectively in the

semi deciduous and evergreen rainforest zones in 2020, 2050 and 2080 respectively. The

multiple regression analysis showed that over 60% of the variation in dry cocoa beans

produced could be explained by the combination of the preceding year’s total annual rainfall,

total rainfall in the two driest months and total sunshine duration. Tobit model showed that,

rainfall, temperature and sunshine were the most important climatic factors that affect cocoa

production.