9CLIMATE VARIABILITY AND SUSTAINABLE FOOD PRODUCTION IN NIGERIA

Abstract

Climate variability has been shown to have significant impacts on global and regional food production particularly the common staple food crops in tropical sub-humid climatic zone. However, the extent and nature of these impacts still remain uncertain. This study investigates the impacts of the variability of climatic variables on some food crops grown in the major ecological zones of Nigeria (rainforest, guinea savanna, sudan savanna and sahel) using Stepwise Multiple Regression Analysis and variability indices. Meteorological (monthly rainfall, minimum temperature, maximum temperature, sunshine hours and relative humidity) and crop yield data (yam, maize, cowpea, millet and sorghum) from 1985 to 2006 were used for the study. The magnitude of the coefficients of correlation (r) was taken as a first approximation of the impacts using the bivariate correlation analysis. Variability indices results (z-value) established the fact that cumulative climate variability particularly rainfall during growing season are significant. The analysis further shows the negative impacts of unfavourable climate conditions that resulted in reduced crop yields in the 1980’s to 1990’s period. The predictive model generated for the crops were significant at α ≤ 0.05 (pvalue) and showed that April, June and September rainfall as well as sunshine duration (SS) during the growing season were the most significant yield predictors of the crops studied. The statistical models further showed that at least 50% of the variation in the yield of crops studied in all the zones could be explained by the predictor variables.