EFFECT OF CLIMATE CHANGE ON KOLANUT PRODUCTION IN NIGERIA

Abstract

ABSTRACT Kolanut is an economical and culturally significant crop in Nigeria, valued for its socio-cultural, medicinal, and commercial importance. Despite its relevance, kolanut production is increasingly threatened by the adverse effects of climate change. This study examined the long-term effect of climate change on Kolanut production in Nigeria, with emphasis on temporal trends and regional climatic variations across major producing States (Ondo, Ogun, Osun, Ekiti, Oyo, Abia, Niger, Edo, Delta, and Cross River). Secondary data on annual kolanut production indices (yield, area harvested and production volume) and climatic variables (temperature, rainfall, relative humidity and wind speed) from the Food and Agriculture Organization and the National Aeronautics and Space Administration (NASA) respectively between 1980 and 2022 were used for the study. Trend analysis, Geographic Information System (GIS) techniques and Fully Modified Ordinary Least Squares (FMOLS) method were used to analyze the data. Results reveal that kolanut output in Nigeria exhibited fluctuating trends from 82,000 tons in 1997 to 177,000 tons in 2015. Areas harvested fluctuated between 91,000ha (1997) and 270,143ha (2010). Temperature trends showed consistent warming from 31.1oC in 1981 to 39.24oC in 2016, while rainfall patterns decreased from an all-time high of 2792.62mm in 1983 to 1371.96mm in 2022, with significant spatial disparities. Also, relative humidity and wind speed were the most stable of the four climatic variables sampled with a range of 82.4% in 1981 to 82.3% in 2022 and 5.49m/s in 1981 to 5.78m/s in 2022 respectively. GIS results show that southern states, experienced pronounced warming and declining rainfall. GIS result shows that the average decadal temperature and rainfall in Ondo, Ogun, Osun, Ekiti, Oyo, Abia, Edo, Delta, and Cross River were between 22oC-26oC to 23oC-27oC and 1300mm-2400mm to 1400mm-2300mm in period 1 (1981-1990) and period 4 (2010-2020) respectively. FMOLS results reveal that the lagged kolanut output (β = 0.879, p<0.01), area harvested (β = 0.605, p<0.01), temperature (β = 0.683, p<0.05) and wind speed (β = 0.233, p<0.01) had significant effects on current kolanut output. However, the lagged value of area harvested (β = -0.515, p<0.01) had a negative effect on current kolanut output. The study concluded that, kolanut yield in Nigeria is affected by climatic changes, particularly temperature and wind speed. It was recommended that farmers should plant windbreak and shade trees to reduce heat and wind stress while continuous training on the climatic requirements of kolanut production should be encouraged among the farmers for better output.