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Journal of Agricultural Economics and Rural Development
JAERD
Vol. 2(1), pp. 022-025, May, 2015. © www.premierpublishers.org, ISSN: 2167-0477
Research Article
Effect of climate change on maize production in
Nigeria
Obasi IO and Uwanekwu GA
Department of Agricultural Economics, Michael Okpara University of Agriculture, Umudike, Nigeria.
The study was conducted in Nigeria. The objective of the study was to examine the effect of
climate change on maize. The data for the study was obtained from secondary sources. The
result shows that the average rainfall and temperature statistics were 1288.311mm and
31.7173oC in Nigeria within the period under study. The average maize output within the
period was 4.84mt while hectarage and yield were 3.36mha and 1.44t/ha respectively. The
result from the study equally shows that the area cultivated and productivity of maize
increased as temperature and rainfall increased. However, there were deceleration of output
and area of maize cultivated which may have been induced by the increase in temperature
and rainfall over these period. Maize productivity accelerated. The climate change variables
show significant effect on maize production with the period under review. Based on findings
from the study, it is recommended that since temperature and rainfall are relatively beyond
the control of farmers, there should be proper enlightenment of the farmers on the proper
climate adaptation practices to employ in order to minimize the adverse effects of climate
change on their output.
Key words: Climate change, rainfall, temperature, maize, output, productivity.
INTRODUCTION
Climate change is a serious environmental threat to
food security and it worsens poverty because of its
impact on agricultural productivity. Almost all sectors of
agriculture depends on weather and climate whose
variability have meant that rural farmers who implement
their regular annual farm business plans, encounters
total failure due to climate change effects (Ozor et al,
2010). Local climate variability can influence people’s
decision, with consequences for their social, economic,
political and personal conditions and can affect their
lives and livelihood (UNFCC, 2007).
Climate change has been defined by the Intergovernmental Panel on Climate Change (IPCC) (2001)
as statically significant variations in weather conditions
that persist for an extended period of time, typically
decades or longer.
There is a scientific consensus that continual
accumulation of heat-trapping “greenhouse” gases in
the atmosphere is contributing to changes in global
climate, and in climates of regions around the world
(Crosson, 1997).
The problem is expected to be most severe in Africa
where current information on climate change is limited,
the technological change slow and the domestic
economy depending heavily on agriculture (Action Aid,
2008). In Nigeria, agriculture is important. About 42% of
the country’s GDP comes from agriculture and related
activities and about 80% of the country’s poor live in
rural areas and work primarily in agriculture (NBS,
2006). Nigeria’s agriculture therefore depends heavily
on climate because temperature, sunlight, water,
relative humidity are the main drivers of crop growth
and yield (Adejuwon, 2004).
*Corresponding Author: Obasi I. Oscar, Department of
Agricultural Economics, Michael Okpara University of
Agriculture, Umudike, Nigeria. Tel.: +2348033551206,
+2348065836666, E-mail: [email protected]
Effect of climate change on maize production in Nigeria
Obasi and Uwanekwu
022
There is a growing consensus in scientific literature that
over the coming decades, higher temperature and
changing precipitation levels caused by climate change
will be unfavourable for crop growth and yield in many
regions and countries including Nigeria (Yusuf et al,
2008).
It is therefore projected that crop yield in Africa may fall
by 10-20% by 2050 or even up to 50% due to climate
change, particularly because African agriculture is
predominantly rained and hence fundamentally
dependent on the vagaries of weather (Jones and
Thornton, 2003).
Most of the crop production in Nigeria are lowtechnology based and are therefore heavily susceptible
to environmental factors and climate change, which are
problems to farmers (Obioha, 2008). Farmers face
challenges of tragic crop failures, reduced agricultural
productivity, increased hunger, malnutrition and
diseases due to adverse effect of climate change
(Zoellick, 2009). These problems hamper agricultural
output and contribution of the agricultural sector to the
Nigeria’s Gross Domestic Product (GDP).
The specific objectives were to:
i.
estimate the average maize output, hectarage,
productivity and climatic parameters from (1980-2010).
ii.
estimate the trend of climatic parameters
(rainfall and temperature) from 1980 – 2010.
iii.
Confirm
acceleration,
deceleration
and
stagnation of the climatic trend variables from 1980 –
2010.
iv.
estimate the significant effect of climate change
on maize crop output.
procedure described by Onyenweaku and Ezeh (1987)
and Onyenweaku and Okoye (2005).
Y
bt
=
boe
……………………………………… (i)
When linearized in logarithm, equation (i) becomes (Y =
bo + bt )
Where: Y
Rainfall, temperature
t
Time and variables
bo,b1 Regression
parameters to estimated.
For objective 3, in order to confirm the existence of
acceleration, deceleration or stagnation in rainfall and
temperature variable in Nigeria, quadratic equation in
time variable was fitted to the data as follows:
Log Q = a + bt + Ct2 …………………………..
(ii)
In the above specification, the linear and quadratic time
terms gives the secular path in the dependent variable
2
(Q). The quadratic time t allows for the possibility of
acceleration, deceleration or stagnation during the
period of the study (Onyenweaku and Okoye, 2005;
Onyenweaku, 1993 and 2004; Sewat, 1981). Significant
positive value of the coefficient of t2 confirms significant
acceleration; significant negative value of t2 confirms
significant deceleration while non-significance of the
2
coefficient of t implies stagnation or absence of either
acceleration or deceleration in the climate variables.
Objective 4 was analyzed by the use of ordinary least
square regression method specified thus;
MATERIALS AND METHOD
Q
This study was carried out in Nigeria. Nigeria's latitude
and longitude are 10° 00' N and 8° 00' E. Nigeria is the
most populous black nation in the world and agriculture
is a major activity especially in the rural areas. The data
(1980- 2010) for the study was obtained from
secondary sources. The sources include reports of
National Bureau of Statistics (NBS), FAOSTAT (The
Food and Agriculture Organization Online Agricultural
Database), production yearbook of Central Bank of
Nigeria (CBN), Ministry of Agriculture and Rural
Development
(FMARD),
several
issues
and
publications of Central Bank of Nigeria, as well as
Annual Reports and Statement of Accounts. Other
complimentary sources include published and
unpublished materials like proceedings, thesis,
textbooks, bulletin and academic journals. Information
from these sources covers variables of interest,
literature and other findings.
The analytical tools employed include descriptive tools
and Ordinary Least Square regression models.
Objectives I was achieved using descriptive statistics.
For objective 2, the trend was computed by fitting an
exponential function in time to data following the
= bo+ b1 x1 + b2 x2 + e ……………………… (iii)
Where Q= maize output, x 1 = rainfall, x2 = temperature.
The four functional of forms of linear, exponential, semilog and Cob Douglas was analyzed and the lead
equation selected based on certain econometric (high
R2 value, F- ratio, number of significant factors) criteria.
RESULTS AND DISCUSSION
Maize output, hectarage, productivity and climatic
parameters.
The average maize output, hectarage productivity and
climatic parameters from 1980-2010 are presented in
Table 1.
The result shows that the average rainfall and
temperature statistics were 1288.311mm and
31.7173oC in Nigeria. The average maize output within
the period was 4.84mt while hectarage and yield were
3.36mha and 1.44t/ha respectively.
Effect of climate change on maize production in Nigeria
J Agric. Econ. Rural Devel.
023
Table 1. Average maize output, hectarage productivity and climatic parameters from 1980-2010
Item
Rainfall
Temperature
Output
Hectarage
Yield
Mean
1288.311
31.7173
4,838,1.09
3,3618.10
1.4419
STD. DER.
97.6199
0.5656
2128530
1461,745
03275
Mini
985.31
308083
612,000
438,000
0.9700
Max
1468.33
33.2667
7,525,000
5,472,000
2.2
Source: FAOSTAT and NIMET. (units: output in metric tonnes, rainfall in millimeter, temperature in Degree Centigrades, yield in
metric tonnes ).
Table 2. Estimated functions for production area and productivity of maize in Nigeria, 1980-2010.
Production:
Constant term (a)
2
Coefficient (b)
R
F
0.5656
37.75***
0.3687
16.94***
0.4635
25.05***
14.2075
0.0623
(76.50***)
(6.14***)
14.0979
0.0475
(66.65***)
(4.12***)
Area:
Productivity:
0.1029
0.0148
(2.01***)
(5.01***)
Figures in parenthesis are t-values, * and *** is significant at 10% and 1% level of probability respectively
Table 3. Estimated function
Rainfall
Temperature
Constant term (a)
7.0731
(299.55***)
3.4405
(606.70***)
Constant term (a)
0.0054
(4.15***)
0.0010
(3.22**)
R2
0.3730
F
17.25***
0.2704
10.38***
Figures in parenthesis are t-values, ** and *** is significant at 5% and 1% level of
probabilities respectively.
Trends in maize production and climate variable in
Nigeria 1980-2010.
variables and this has a possibility of affecting crop
performance.
From Table 2, the coefficients of the trend variable
were all highly significantly at 1% level of probability
indicating that output, area and productivity of maize in
Nigeria increased with time within the period under
review. The means that area cultivated increased as
well as productivity irrespective of the climatic condition
within this period.
Confirmation of Acceleration, Deceleration and
stagnation of maize production and climatic
variables in Nigeria: 1980-2010
Trend in rainfall temperature variables in Nigeria:
1980-2010.
Table 3 shows the estimated log linear function in time
variable for rainfall and temperature within the period
and it showed positive trends. The coefficient of the
trend variables for rainfall was highly significant at 5%
level of probability. This implies that rainfall and
temperature increased with time within the period. The
coefficient in Table 3 also shows the relationships. The
implication is that there was increase in these climatic
From Table 4, the coefficients of the b2 for temperature
and rainfall were negatively signed but not significant.
The non-significance of the coefficient of b2 was a
confirmation of stagnation within the period following
Madu and Chinaka 2011. This implies a relative
stagnation of maize output within this period because
there was no significant increase or decrease. This
may be attributed to the variation on climatic conditions.
Confirmation of Acceleration, Deceleration and
stagnation of production, area and productivity of
maize in Nigeria. 1980-2010.
The coefficients of b2 for output and area were
negatively signed and highly significant at 1% level of
Effect of climate change on maize production in Nigeria
Obasi and Uwanekwu
024
Table 4. Estimated quadratic function in time variable for rainfall and
temperature in Nigeria. 1980-2010.
Defendants variable
Estimated coefficients
bo
7.0497
(189.85***)
3.4389
(380.07***)
Rainfall
Temperature
b1
0.0096
(1.79*)
0.0013
(0.99)
2
b2
-0.0013
(-0.82)
-0.0000088
(-0.22)
R
0.3877
F
8.86**
0.2717
5.04*
Figures in parentheses are t-values. *,*,*, and *** is significant at 10%, 5% and 1%
respectively.
Confirmation of Acceleration, Deceleration and stagnation of production, area and
productivity of maize in Nigeria. 1980-2010.
Table 5. Estimated quadratic functions in time variables for output, Area and
productivity of maize in Nigeria.
Defendants variable
Estimated coefficients
Production
bo
13.3066
(67.99***)
12.9514
(70.39***)
0.3540
(5.71***)
Area
Productivity
b1
0.2261
(8.02***)
0.2559
(9.66***)
-0.0296
(-3.32**)
b2
-0.0051
(-5.99**)
-0.0065
(-3.11***)
0.0014
(5.13***)
R2
0.8095
F
59.49***
0.8113
60.21***
0.7236
36.66***
Figures in parentheses are f-values ** and *** is significant at 5% and 1% level of
probability respectively.
Table 6. Regression estimates of the effect of climatic variables
in maize output, hectarage and yield in Nigeria 1980-2010.
Variable
Constant
Output
(semi-log)+
Hectarage
(double log+)
Yield
(Semi-log+)
-284052574
-60.1031
-27.3099
(-5.42)
(-2.67*)
(-2.83**)
13913496
3.1299
1.6133
(4.09***)
(2.14*)
(2.58*)
54769251
15.2048
4.9770
(3.53**)
(2.28*)
(1.75*)
R
0.5988
0.3332
0.3283
F
(20.14***)
6.75**
(6.60**)
Rainfall
Temperature
2
Figures in parentheses are f-values ** and *** is significant at 5% and
1% level of probability respectively.
probability as shown in Table 5. This implies a
confirmation of deceleration of output and area of
maize within the period, (Chi-Chung et al, (2004). The
coefficient of the b2 for productivity was positively
signed and highly significant at 1% level of probability.
This implies a confirmation of acceleration of yield
within the period under review. This may be related to
better management of the farm to increase output per
area cultivated.
Effect of climatic variables on maize output,
hectarage and yield of maize in Nigeria.
The results from Table 6 show that the semi-log
functional form was chosen as the lead equation
because of a high R2 value of 0.5988 which indicates
59.88% variability in maize output explained by the
climatic variables. The F- ratio was highly significant at
1% indicating a regression of best fit. The coefficients
of rainfall and temperature were positively signed and
significant, this implies that increase in rainfall and
temperature to corresponding increases in maize
output at a deceleration within the period.
For maize hectarage, the Cobb Douglas functional farm
was chosen as the lead equation because of a high R2
value of 0.3332 indicating 33.32% variability in
hectarage of maize explained by the climatic variables.
The result showed that increase in climatic variable led
Effect of climate change on maize production in Nigeria
J Agric. Econ. Rural Devel.
to corresponding increases in area planted with maize
within the period though with a deceleration.
The result for maize yield revealed that the semi-log
functional form was chosen as the lead equation
because of a higher number of significant variables with
a R2 value of 0.3283 indicating a 32.83% variability in
maize yield explained by the independent variables.
The coefficients of rainfall and temperature were all
positively signed and significant; this implies that
increases in the climatic variables led to corresponding
increases in maize yield. Therefore, generally, there
was an increase in output, hectarage and yield within
this period but at decreasing rate. This shows that even
though increases were recorded with the increase in
the climatic variables, the effect of these climatic
variables was shown through the decelerating rate of
output, hectarge and yield.
CONCLUSION AND RECOMMENDATIONS
Based on the findings of the research on this study,
climate change significantly affected the productivity of
maize crop in Nigeria. As temperature and rainfall
increased, there were increases in output and area at a
deceleration which may have been induced by climate
change. This goes a long way indicating the importance
of climate to crop production. Thus, climate variability is
an important determinant resource for crop production
in Nigeria very important to agriculture in Nigeria.
Considering the result of the analysis, the following
recommendations were made:
i.
There is need for governmental policies
towards mitigation measures, such as conservation of
resources and the development and deployment of
alternative energy sources, massive campaign on
green house gas emission activities in the country.
ii.
The government should gear efforts towards
developing technologies such as research and
extension methodologies, which will address changes
in climate, as well as providing effective irrigation
facilities.
iii.
The
use
of
environmentally
friendly
equipments,
machines,
infrastructures
and
technologies that produces less of the green houses
gases emphasized. Partnerships between government
and other stakeholders, farmers, private sectors and
local communities to ensure a win-win situation against
climate risks should be encouraged.
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18
Accepted 07 April, 2015
Citation: Obasi IO, Uwanekwu GA (2015). Livestock Policies
and its Impact on India and Bihar, State. Journal of
Agricultural Economics and Rural Development, 2(1): 022025.
Copyright: © 2015. Obasi IO and Uwanekwu. This is an
open-access article distributed under the terms of the
Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any
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Effect of climate change on maize production in Nigeria