Towards sustainable crop production in Somalia: Examining the role of environmental pollution and degradation

Figures & data

Figure 1. Environmental pollution and degradation in Somalia. Data source: World bank, (2022).

Figure 2. Trends of the interested variables.

Source: World Bank (2021)

Table 1. Descriptive statistics

	lnCPI	lnDEFO	lnCO2	lnPG	lnAM	lnCC
Mean	4.542996	13.89731	6.401381	0.769185	9.674391	13.09605
Median	4.535606	13.85761	6.429719	1.020044	9.689056	13.17537
Maximum	4.890650	14.11562	6.593045	1.333717	9.769385	13.80283
Minimum	4.293059	13.81551	6.194405	−1.271731	9.446203	12.46843
Std. Dev.	0.132290	0.082706	0.100121	0.722651	0.069188	0.294151
Skewness	0.162899	1.501537	−0.382066	−1.887335	−1.691473	−0.150597
Kurtosis	3.503905	4.491846	2.647770	5.382301	6.131657	3.231557
Jarque-Bera	0.405073	12.64957	0.796459	22.41392	23.90805	0.162379
Probability	0.816657	0.001791	0.671508	0.000014	0.000006	0.922019
Correlation
lnCPI	1.000000	0.366098	0.196944	0.393145	0.564205	0.299023
lnDEFO	0.366098	1.000000	−0.150308	0.347844	0.568313	0.271999
lnCO2	0.196944	−0.150308	1.000000	−0.559658	−0.504531	−0.230388
lnPG	0.393145	0.347844	−0.559658	1.000000	0.901684	0.002999
lnAM	0.564205	0.568313	−0.504531	0.901684	1.000000	0.173054
lnCC	0.299023	0.271999	−0.230388	0.002999	0.173054	1.000000

Table 2. Result of the ADF and PP unit root tests

Variable	ADF	PP
lnCPI	−5.3519***	−5.2552
ΔlnCPI	−5.7455***	−9.4507***
lnCO2	−2.3364	−2.2425
ΔlnCO2	−3.5749*	−3.5861**
lnDEFO	−2.8447	−2.0676
ΔlnDEFO	−4.0681**	−3.948**
lnAM	−3.3499*	−2.2245
ΔlnAM	−4.5719***	−5.4186***
lnCC	−4.2281**	−4.6593***
ΔlnCC	−5.1289***	−18.0669***
lnPG	−0.1406	−1.8737
ΔlnPG	−6.4823***	−2.9653

***, **, and * represent significance level at 1%, 5%, and 10%. Δ stands for the first difference level, and in is the natural logarithm.

Table 3. F-bounds cointegration tests

Model F-statistic significance level	Bounds test critical values
LnCPI = f(lnCO2, lnAM,			K (5)
lnPG, lnDEFO, lnCC)
			I (0)	I (1)
	17.3171%	4.483		6.32
		5%	3.12	4.56
		10%	2.56	3.828

Table 4. Long-run coefficient elasticities

Explanatory Variable	Coefficient
lnCO2	0.566147*** (9.4343)
lnAM	1.9502*** (−7.3677)
lnPG	−0.0882*** (−6.3838)
lnDEFO	−0.2520** (−2.5123)
lnCC	0.0193 (0.7288)

Notes: ***, ** and * exhibit significance level at 10%, 5%, and 1%.T-statistic values are in (.) parenthesis and P-values are in [.] parenthesis.

Table 5. Short-run dynamic effect and diagnostic test

Variable	Coefficient (T-Statistic)
Constant	−12.1258***
	(−3.7772)
ECT(−1)	−0.8299***
	−3.7795
Δ (lnCPI(−2))	0.107566
	(1.0991)
Δ (lnCO2)	0.989963**
	(2.5333)
Δ (lnDEFO)	(0.0323)
	0.138526
Δ (lnPG)	−0.124681*
	(−2.0149)
Δ (lnCC)	0.149542***
	(3.4167)
Δ (lnAM)	1.1015*
	(1.8273)
Diagnostics test
Ramsey test	1.9472 [0.2123]
Adjusted R-square	0.9555
Breusch-Godfrey test	0.4146 [0.1814]
Breusch-Pagan test Normality	0.3519 [0.8276] 0.0103 (0.9948)

Notes: ***, ** and * indicates significance level at 10%, 5%, and 1%.T-statistics values are in (.) parenthesis. P-values are in [.]

Figure 3. Cusum test.

Figure 4. Cusum square test.

Table 6. Method: Fully modified ordinary least squares (FMOLS)

Variable Coefficient Std. Error t-Statistic Prob.
lnCO2	1.116067	0.124485	8.965450	0.0000
lnDEFO	−0.265449	0.158116	−1.678825	0.1087
lnPG	−0.004273	0.033800	−0.126407	0.9007
lnCC	0.176758	0.034984	5.052554	0.0001
lnAM	1.751580	0.410394	4.268041	0.0004
Constant	−18.16238	3.054893	−5.945343	0.0000
R-squared	0.607581
Adjusted R-squared	0.509477

Table 7. Pairwise granger causality tests

Null Hypothesis:	F-Statistic	Prob.
lnDEFO → lnCPI	0.56679	0.4592
lnCPI → lnDEFO	0.91243	0.3494
lnCO2 → lnCPI	4.30914	0.0493**
lnCPI → lnCO2	5.56496	0.0272**
lnAM → lnCPI	7.93075	0.0098***
lnCPI → lnAM	9.75504	0.0048***
lnPG → lnCPI	5.03797	0.0347**
lnCPI → lnPG	4.36474	0.0479**
lnCC → lnCPI	5.88985	0.0235**
lnCPI → lnCC	2.36423	0.1378
lnCO2 → lnDEFO	0.62228	0.4376
lnDEFO → lnCO2	0.78420	0.3843
lnAM → lnDEFO	1.23837	0.2764
lnDEFO → lnAM	0.13833	0.7131
lnPG → lnDEFO	0.80040	0.3795
lnDEFO → lnPG	0.00135	0.9710
lnCC → lnDEFO	0.28160	0.6003
lnDEFO → lnCC	0.01123	0.9165
lnAM → lnCO2	5.05564	0.0336**
lnCO2 → lnAM	8.82668	0.0065***
lnPG → lnCO	24.68311	0.0402**
lnCO2 → lnPG	4.78647	0.0382**
lnCC → lnCO2	3.27548	0.0824*
lnCO2 → lnCC	2.72637	0.1112
lnPG → lnAM	0.27404	0.6052
lnAM → lnPG	1.24183	0.2757
lnCC → lnAM	0.38436	0.5409
lnAM → lnCC	0.09847	0.7563
lnCC → lnPG	0.07490	0.7866
lnPG → lnCC	1.05110	0.3151

signify that variable “x” does not granger cause variable “y”

World Bank. (2022). data.worldbank.org. Retrieved from https://data.worldbank.org/indicator/AG.LND.ARBL.HA?locations=SO

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Data availability statement

The datasets used and/or analyzed during the current study are available from the following link:

https://data.worldbank.org/indicator/AG.PRD.CROP.XD?locations=SO

https://www.sesric.org/query.php

https://climateknowledgeportal.worldbank.org/download-data

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