Industrialization and carbon emission nexus in Sub-Saharan Africa. The moderating role of trade openness

Figures & data

Table 1. Description of variables.

Variables Categories	Variables	Symbol	Measurement	Sign
Dependent	Carbon Emission	lnCO2M	Natural logarithm of CO2 emissions (metrics tons per capita)
Independent	Industrialisation	lnIDT	Natural logarithm of the proportion of industry (such as construction, value added) to % of GDP	+
Moderating	Trade openness	lnTOP	Natural logarithm of the export-to-import ratio expressed as a % of GDP	+
Control	Urban population growth	lnUPG	Natural logarithm of the growth in urban population (yearly%)	+
	Energy Consumption	lnEC	Natural logarithm of energy usage per capital (measured in kilogrammes of oil equivalent per capital)	+
	Gross Fixed Capital Formation	lnGF	Natural logarithm of Gross Fixed Capital Formation (annual percentage growth)	−
	Economic Growth	lnEG	Natural logarithm of the Difference between current year growth from previous year’s growth rate.	+

Table 2. Descriptive statistics.

Variable	Obs	Mean	Std. Dev	Min	Max	Skewness	Kurtosis
InCO2M	532	4.5698	7.9096	0	7.9096	2.8687	6.057
InIDT	532	7.0412	13.096	0	13.096	1.1854	3.9945
InTOP	532	3.8952	6.2955	−18.917	6.2955	1.7564	3.0332
InUPG	532	3.2052	2.798	0	532.88	2.5643	11.851
InEC	532	3.9396	1.3306	0	1.3306	3.7773	12.45
InGF	532	3.0949	4.3647	−.01414	4.3647	4.5863	10.964
InEG	532	0.6604	1.5009	−14.144	1.4729	−1.5784	9.5761

Table 3. Friedman’s CD Test.

Test	Statistics	p-values
Fixed Effect (FE) Analysis	19.584	.0014
Random Effect (RE) Analysis	28.341	.0028

H₀ is no cross-section dependency.

The p-values are in italic.

Table 4. LLC Unit root test results.

Variable	Adjusted	p-value
InCO2M	7.0533	.0000
InIDT	−8.0204	.0000
InTOP	−10.6725	.0000
InUPG	−7.7083	.0000
InEC	−3.5599	.0000
InGF	−9.8148	.0000
InEG	−5.9157	.0000

H₀ is no stationarity.

The p-values are in italic.

Table 5. CIPS and ADF unit root tests.

	CIPS
	Level
Variable	Constant	Constant & Trend	ADF
InCO2M	−3.4863***	−5.4937***	−3.4748***
InIDT	−2.9856***	−4.4638***	−4.3483***
InTOP	−3.5729***	−5.482***	−6.3745***
InUPG	−2.9732***	−5.4732***	−4.3785***
InEC	−2.9482***	−6.3646***	−7.4743***
InGF	−3.4721***	−4.3802***	−9.5743***
InEG	−3.5792***	−5.9532***	−6.3968***

*** denote statistical significance at 1%.

Table 6. Estimation results.

	Panel A		Panel B		Panel C		Panel D		Panel E
variables	(R1)	(R2)	(R1)	(R2)	(R1)	(R2)	(R1)	(R2)	(R1)	(R2)
L.InCO2M	0.3275***		0.2635***		0.4736***		0.3453***		0.5487***
InIDT	0.3745***	0.1047***	0.1073**	0.1498**	0.2174***	0.1352***	0.2534***	0.0653***	0.1432***	0.2354***
InUPG	0.1241*	0.1421	0.2039*	0.2135	0.2164**	0.1463	0.1682**	0.1746**	0.2465*	0.1635
InEC	0.2643***	0.2047***	0.1264***	0.2635***	0.1264***	0.2645***	0.1637***	0.2635***	0.2538***	0.3726***
InGF	−0.1736	−0.0857	0.0946	0.0146	0.2746	0.1374	0.12642	0.0948	0.14763	0.1463
InEG	−0.1327**	−0.0957	−0.6173*	−0.2634	−0.1236**	−0.0949**	−0.1362	−0.0954	−0.1635**	−0.2464**
Wald chi^2	374.56		647.57		573.56		684.57		957.83
Prob > chi^2/AR (2)	0.0000	0.5736	0.0000	0.6483	0.0000	0.7894	0.0000	0.6473	0.0000	.8261
Hansen Test	0.6741		0.5683		0.7832		0.5464		0.8242
Sargan Test	693.22		473.48		447.63		674.59		1265.11
Obs.	57	76	57	76	152	171	190	209	468	532

The coefficients with its significance level for each of the variables are presented in the multiple regression table.

*** denote statistical significance at 1%, ** denote statistical significance at 5%, *denote statistical significance at 10%.

Figure 1. Average carbon dioxide emissions over the periods.

Table 7. Moderating analysis.

	Panel A		Panel B		Panel C		Panel D		Panel E
Variables	M1	M2	M1	M2	M1	M2	M1	M2	M1	M2
L.InCO2M	0.3645***		0.4726***		0.5736**		0.3746**		0.5115***
InIDT	0.4736***	0.3467***	0.4281**	0.4825**	0.3928**	0.3538***	0.5384***	0.4839***	0.5928***	0.3947***
InIDT × InTOP	0.2746***	0.1746***	0.2746**	0.2598**	0.2847**	0.1476***	0.4837***	0.2846***	0.3095***	0.2846***
InTOP	0.4736**	0.2847**	0.3846**	0.3948*	0.4837**	0.1473**	0.1364***	0.1463***	0.2846***	0.1374**
InUPG	0.2384	0.1276	0.3287***	0.1264**	0.2164	0.3281	0.2587**	0.3298*	0.3475**	0.4286*
InEC	−0.1847**	−0.2735**	−0.1836**	−0.3847*	−0.2837**	−0.2926**	−0.2112	−0.1211	−0.2711**	−0.1732*
InGF	0.2746**	0.1836**	−0.1487	−0.1364	0.1763	0.2036	0.1521**	0.3726**	0.2736	0.2631**
InEG	0.1273**	0.2735***	0.1746***	0.1827**	0.4642***	0.2614***	.2731***	0.1648**	0.3824**	0.2164***
Wald chi^2	684.58		568.74		483.18		607.46		1184.48
Prob > chi^2/AR (2)	0.0000	0.5731	0.0000	0.6743	0.0000	0.7836	0.0000	0.6782	0.0000	0.8746
Hansen Test	0.5673		0.6739		0.5847		0.4893		0.7858
Sargan Test	978.47		684.93		793.28		578.47		1382.49
Obs.	57	76	57	76	152	171	190	209	468	532

The coefficients with its significance level for each of the variables are presented in the multiple regression table.

*** denote statistical significance at 1%.

** denote statistical significance at 5%.

* denote statistical significance at 10%.