Page 1 of 13
European Journal of Applied Sciences – Vol. 12, No. 1
Publication Date: February 25, 2024
DOI:10.14738/aivp.121.16334
Ideki, O., Nwaerema, P., & Abali, T. P. (2024). Effect of Climate Variability on Crop Yield in Nigeria (1980-2020). European Journal
of Applied Sciences, Vol - 12(1). 290-302.
Services for Science and Education – United Kingdom
Effect of Climate Variability on Crop Yield in Nigeria (1980-2020)
Ideki, O.
Atmospheric Sciences, School of Natural Resources,
University of Missouri-Columbia USA
Nwaerema, P.
Department of Geography,
Ibrahim Babangida University, Lapai, Niger State Nigeria
Abali, T. P.
Department of Geography and Environmental Management,
Rivers State University Port Harcourt Nigeria
ABSTRACT
This study examined the effect of climate variability on crop yield from 1980-2020
in Nigeria. Rainfall and temperature data were obtained from the Community
Climate System Model website. In contrast, the crop yield of five cereal crops namely
cassava, maize, sweet potatoes, yam, and plantain were obtained from the African
Center for Statistics of the United Nations Economic Commission for Africa (UNECA)
Addis Ababa for the same period. The data sets were analyzed using descriptive and
inferential statistics. The results of the analysis revealed that the mean values of
rainfall and temperature are 1259.4237mm and 25oC respectively for the 41 years
of the study. Furthermore, the regression analysis indicates an increasing trend for
the two climate parameters. At the same time, cassava has the highest yield of
101,449.4390 hg/ha the highest followed by yam 920,75.2678hg/ha, plantain
622,92.3659 hg/ha, sweet potatoes 475,06.0488hg/ha and the crop with the least
yield was maize 146,60.0488 hg/ha. However, the analysis of the effect of climate
variability on crop yield revealed that sweet potatoes and maize correlated
significantly with rainfall and temperature demonstrating the effect of climate
variability on crop yield. This implies that both maize and sweet potatoes were the
most sensitive to climate variability while cassava, plantain, and yam were the least
sensitive crops. The study recommended mainstreaming the weather index crop
insurance scheme into the Nigeria Agricultural Insurance Corporation (NAIC) to
help and modulate the loss and production risk arising from extreme climate
events. There is also a need to pay close attention to factors outside rainfall and
temperature in explaining low and inconsistent yield in Nigeria. Also, farmers
should take factors like soil fertility, untimely planting, improper selection of
cropping systems, diseases, and pest infestation among others into consideration
Keywords: Climate change, crop yield, Agriculture, climate risk, Nigeria
INTRODUCTION
Climate change continues to pose a significant threat to Africa, which has been described as the
most vulnerable continent to the impacts of climate change. The vulnerability is driven mainly
Page 2 of 13
291
Ideki, O., Nwaerema, P., & Abali, T. P. (2024). Effect of Climate Variability on Crop Yield in Nigeria (1980-2020). European Journal of Applied Sciences,
Vol - 12(1). 290-302.
URL: http://dx.doi.org/10.14738/aivp.121.16334
by a range of factors that include weak adaptive capacity, dependence on productive resources
that are climate-sensitive, Africa’s geographical location in the lower latitudes and widespread
poverty (World Bank,2020). There is evident that the intensification, pace and scale of climate
change impact will compromise the growth and development of the agricultural and other
economic sectors which are the key engines of Africa’s development objectives. Rising
temperatures with the year 2019 described as the warmest year in Africa and nine out of the
ten warmest years since 2005 and rainfall variability leading to drought and floods of different
magnitude are already manifesting in Africa leading to decline in agricultural productivity and
GDP contraction (AfDB, 2019). In Nigeria, agriculture particularly the crop sub sector is the
major supplier of stable food. The crop sub sector of the agricultural value chain predominately
practiced in the rural areas is plagued by poor knowledge of meteorological variables, poor
infrastructures and low income. Crop yield which is the output of generated from planting from
a given unit of land currently contributes 40% of Nigeria GDP (Suifiyan et al, 2022). The major
cereal crops consumed in Nigeria include cassava, yam, plantain maize and sweet potatoes.
Similarly, agriculture which has been described as the main stay of the Nigerian economy
despite many years of oil exploitation accounts for over 65% of employment among rural
dwellers. Despite its enormous contribution to the Nigerian economy, the agricultural sector is
confronted by myriad of challenges which include soil fertility problems, climate and diseases.
With respect to climate, the two factors that are critical to crop productivity are rainfall and
temperature. This is more evident given the fact that they determine soil moisture content and
distribution of crops and livestock in any agro-ecological zone (Mesike, 2016).
Studies of rainfall variability in Nigeria reveal progressive decline in the frequency and
intensity of rainfall both in the northern and southern regions of the country which could be
devastating to crop yield. Therefore, understanding the effect of climate variability on crop
yield is critical in improving resilience and building adaptation of agricultural production
systems to climate change. Adaptation measures such as shifting planting dates, planting early
maturing crop, changes in crop growing pattern may help mitigate negative impacts of climate
change on crop yield and production. Most studies on the effect of climate variability and crop
yield in Nigeria are concentrated at the states and regional level not the country and this is
where this study derives its relevance. Very few studies have indicated the fact that climate can
affect crop yield but they did not consider the effect on food crops which are even counted as
staple foods in Nigeria. Thus, the present study is examining the effect of climate
variability/change on crops yield for the periods from 1980 to 2020 in Nigeria with a view of
analyzing the rainfall a temperature trend in from 1980 to 2020 and finding the effect of rainfall
and temperature variation on crop yield from 1980 to 2020.
MATERIAL AND METHODS
The study was carried out in the entire Nigeria, Nigeria is located on latitudes between 4o N and
14o N and longitudes between 2o E and 15oE. It occupies an area of 923,768sqkm as shown in
Figure 1. The climate of Nigeria varies from equatorial in the south to arid in the North and
tropical in the center. Precipitation is heavier in the south receiving 3,000mm of rain per year
and decreases progressively away from the coast to the far North. Temperature is relatively
constant all year round.
Page 3 of 13
Services for Science and Education – United Kingdom 292
European Journal of Applied Sciences (EJAS) Vol. 12, Issue 1, February-2024
Extraction of Meteorological Data (Precipitation and Temperature)
The point grid pattern of meteorological data was obtained for total precipitation, and air
temperature from 1980 to 2020 to monitor the climate pattern overtime from Community
Climate System Model website which is available from https://gisclimatechange.ucar.edu/gis- data.
The crop yield data was obtained from the African center for statistics of the United Nations
economic commission for Africa (UNECA Addis Ababa). Food crops were basically selected
because of their importance as staple foods and the level of their consumption in the country.
These selected crops included cassava, maize, potatoes, plantain and yams.
Both descriptive inferential statistics were employed for the data analysis. The descriptive
statistics included the mean and standard deviation. The inferential statistics used included the
multiple regression analysis and One Way analysis of variance (ANOVA) was employed to test
some hypotheses. The simple regression analysis was used to determine the relationship
between the climate parameters and the crop yield whereby the crop yield was found to be the
dependent variable (Y) and the climate parameters were regarded as independent variables
(x1, x2). The ANOA was used to determine the significant temporal difference in the crop yield
and climate parameter over the years being considered for this study.
Figure 1: Nigeria showing the 36 States
RESULTS AND DISCUSSIONS
Descriptive Analysis of Climate Parameters and Crop Yields
The analysis in Table 1 indicates that the mean precipitation between 1980 and 2020 was
1259.42 ±40.9 mm while the mean temperature was 25.29 ±0.3°C. The mean crop yield for
cassava was 101449.44±12987.20 hg/ha and that of maize was 14660.05±2516.03 hg/ha,
Page 4 of 13
293
Ideki, O., Nwaerema, P., & Abali, T. P. (2024). Effect of Climate Variability on Crop Yield in Nigeria (1980-2020). European Journal of Applied Sciences,
Vol - 12(1). 290-302.
URL: http://dx.doi.org/10.14738/aivp.121.16334
potatoes 47506.05±16044.06 hg/ha, yams 92075.27±20890.65 hg/ha and plantains having the
mean values of 62292.37±7176.59 hg/ha. This implies that the yield of cassava was the best
during the period considered for the study while maize was the least. Yam was the next to
cassava. The higher crop yield of cassava and yams could be attributed to the fact that both are
relatively surviving the harsh weather conditions especially during the period high rainfall
intensity and hot weather.
A cursory look at Table 2 reveals that temperature varies significantly (F=28.03, p<0.05) in the
all the years of the study (1980-2020). Similarly, the yield of all the crops used for the study
varied significantly among the years. This implies that temperature was critical to the growth
and yield of the crops. We can infer that the summary statistics is significant as crop yield is
explained the amount of rainfall and temperature received over the years. Rainfall and
temperature trend from 1980 to 2020 is shown in Figure 2. The result indicates upward and
increasing temperature trend from 1980 to 2020 while precipitation showed fluctuating trend.
However, from 2017, increasing trend in precipitation was observed in the country which is
pivotal to crop production which is another evidence of climate variability.
Similarly, analysis of crop yield from 1980 to 2020 was carried to ascetain yield trend. The
result as shown in Figure 3 indicates that cassava and yam are the only two crops with higher
in yield and their trend was similar which further points to high tolerance of climate variability.
The yield of the other 3 crops namely potatoes, maize, plantain and others was inconsistent and
may be attributed to unfavourable weather condition since rainfall and temeprature are key
climate parameters that influence crop yield. others similar yeild and the minimum crop yield
through the period of study was maize.
Table 1: Annual Analysis of Data from 1980 to 2020
Descriptive Statistics
N Minimum Maximum Mean Std. Deviation
Precipitation (mm) 41 1189.53 1389.69 1259.4237 40.90743
Temperature (°C) 41 24.60 25.86 25.2871 .36528
Cassava (hg/ha) 41 70323.00 122155.00 101449.4390 12987.19822
Maize (hg/ha) 41 9707.00 21961.00 14660.0488 2516.02711
Potatoes (hg/ha) 41 24610.00 72727.00 47506.0488 16044.05910
Yams (hg/ha) 41 56284.00 130109.00 92075.2683 20890.64716
Plantains (hg/ha) 41 48995.00 75372.00 62292.3659 7176.59821
N= 41
Table 2: Analysis of variance
Sum of Squares df Mean Square F Sig.
Precipitation Between Groups 16009.508 7 2287.073 1.482 .208
Within Groups 50927.209 33 1543.249
Total 66936.717 40
Temperature Between Groups 4.569 7 .653 28.027 .000
Within Groups .768 33 .023
Total 5.337 40
Cassava Between Groups 4928376269.181 7 704053752.740 12.778 .000