Submitted:
13 January 2026
Posted:
14 January 2026
You are already at the latest version
Abstract
Keywords:
1. Introduction
2. Background
3. Literature Review and Theoretical Framework
3.1. Energy Consumption and Environmental Degradation: Environmental Phillips Curve Hypothesis (EPC)
3.2. Environmental Kuznets Curve (EKC) Hypothesis
3.3. Review of Empirical Literature on Socio-Economic and Energy-Related Factors
4. Materials and Methods
4.1. Model Specification
4.2. Unit Root Test
4.3. Autoregressive Distributed Lag (ARDL) Model
5. Results
5.1. Descriptive Statistics
5.2. Unit Root Results
5.3. Co-Integration Test
5.4. Long-Run ARDL Results
5.5. Short-Run Results
6. Discussion
7. Conclusions
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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| Variable | Denotation | Measurement |
|---|---|---|
| Environmental degradation | CO2 | Emissions from the consumption of fossil fuels (coal, oil, gas, & flaring) and cement manufacturing, measured in millions of tons. |
| Financial development | FD | proxied by total credit extended to the domestic private sector. Measured in thousands of thousands of rands. |
| Renewable energy | RE | sum of energy produced by solar, wind, hydro, and biomass, measured in terawatt-hours (Twh). |
| non-renewable energy | NRE | sum of energy produced from coal, gas, nuclear, and oil, measured in terawatt-hours (Twh). |
| Unemployment rate | UNE | % of the labour force without job and is actively seeking employment. Number of Unemployed Individuals / Total Labor Force) x 100. |
| Gross domestic product per capita | GDPPC | GDPPC = . Measured in thousands of rands. |
| Population growth | PoPG | Population growth = ( is the population for current year while is the previous year’s population. Measured in percentages. |
| lnCO2 | lnRE | lnNRE | lnFD | lnGDPPC | lnUNE | lnPoPG | |
|---|---|---|---|---|---|---|---|
| Mean | 19.83199 | 1.905622 | 6.842393 | 11.10335 | 10.59556 | 3.204458 | 0.193221 |
| Maximum | 20.01946 | 3.916582 | 6.995005 | 12.95522 | 11.60443 | 3.535145 | 0.826218 |
| Minimum | 19.53270 | -0.839977 | 6.644770 | 7.995307 | 9.240870 | 2.827314 | -0.424896 |
| Std. Dev | 0.132203 | 1.101700 | 0.110610 | 1.347595 | 0.736088 | 0.141324 | 0.303079 |
| Skewness | -0.651467 | 0.138099 | -0.356087 | -0.587482 | -0.312028 | -0.077501 | 0.070162 |
| Kurtosis | 2.365489 | 2.868652 | 1.809568 | 2.316204 | 1.773277 | 4.115382 | 2.412554 |
| Jarque-Bera | 2.800322 | 0.124717 | 2.565759 | 2.464155 | 2.525729 | 1.690802 | 0.486377 |
| Probability | 0.246557 | 0.939546 | 0.277238 | 0.291686 | 0.282843 | 0.429385 | 0.784124 |
| ADF | ||||||
|---|---|---|---|---|---|---|
| Variables | Level | 1st diff | ||||
| Intercept | Trend & Intercept | None | Intercept | Trend & Intercept | None | |
| lnCO2 | 0.3514 | 0.9223 | 0.8655 | 0.0000*** | 0.0000*** | 0.0000*** |
| lnRE | 0.5870 | 0.0120** | 0.6103 | 0.0000*** | 0.0000*** | 0.0000*** |
| lnNRE | 0.3135 | 0.8167 | 0.8647 | 0.0000*** | 0.0001*** | 0.0000*** |
| lnFD | 0.0524* | 0.0815* | 0.9994 | 0.0000*** | 0.0004*** | 0.0000*** |
| lnUNE | 0.8256 | 0.5164 | 0.8906 | 0.0006*** | 0.0026*** | 0.0021*** |
| lnGDPPC | 0.0010*** | 0.9953 | 0.9697 | 0.0212** | 0.0011*** | 0.2784 |
| lnPoPG | 0.0512* | 0.1532 | 0.0190** | 0.2573 | 0.0001*** | 0.0321** |
| Phillips-perron | ||||||
|---|---|---|---|---|---|---|
|
Variable |
Level | 1st diff | ||||
| Intercept | Trend & Intercept | None | Intercept | Trend & Intercept | None | |
| lnCO2 | 0.3587 | 0.9630 | 0.8729 | 0.0000*** | 0.0000*** | 0.0000*** |
| lnRE | 0.6966 | 0.0120** | 0.7987 | 0.0000*** | 0.0000*** | 0.0000 |
| lnNRE | 0.3225 | 0.9115 | 0.9014 | 0.0000*** | 0.0000*** | 0.0000*** |
| lnFD | 0.0300** | 0.0858* | 0.9993 | 0.0000*** | 0.0000*** | 0.0000*** |
| lnUNE | 0.8217 | 0.4905 | 0.9481 | 0.0003*** | 0.0006*** | 0.0000*** |
| lnGDPPC | 0.0013*** | 0.9953 | 1.0000 | 0.0196** | 0.0011*** | 0.2678 |
| lnPoPG | 0.0643* | 0.3145 | 0.0246** | 0.0000*** | 0.0000*** | 0.0000*** |
| Test Statistic | Value | Signif. | I(0) | I(1) |
|---|---|---|---|---|
| F-statistic K |
22.79664 6 |
1% | 2.88 | 3.99 |
| 5% | 2.27 | 3.28 |
| Variable | Coefficient | Std.err | t-statistic | P-value |
|---|---|---|---|---|
| LnCO2 | 0.105412 | 0.084163 | 1.252482 | 0.2296 |
| lnRE | 0.020549 | 0.006607 | 3.110070 | 0.0072*** |
| lnRE(-1) | 0.015475 | 0.005510 | 2.808407 | 0.0132** |
| lnFD | 0.011651 | 0.016167 | 0.720642 | 0.4822 |
| lnFD(-1) | -0.028079 | 0.014275 | -1.962798 | 0.0685* |
| lnFD(-2) | -0.037080 | 0.015582 | -2.379735 | 0.0310** |
| lnUNE | -0.032371 | 0.044564 | -0.726403 | 0.4788 |
| lnPoPG | 0.015751 | 0.014553 | 1.082343 | 0.2962 |
| lnPoPG(-1) | -0.018175 | 0.016712 | -1.087546 | 0.2940 |
| lnPoPG(-2) | -0.074021 | 0.020399 | -3.682708 | 0.0025*** |
| lnNRE | 0.744821 | 0.100766 | 7.391614 | 0.0000*** |
| lnGDPPC | 1.201628 | 0.192998 | 6.226118 | 0.0000*** |
| lnGDPPC(-1) | -0.434713 | 0.227808 | -1.908239 | 0.0757* |
| lnGDPPC(-2) | -0.193472 | 0.165226 | -1.170956 | 0.2599 |
| Cons | 6.878929 | 1.398905 | 4.917367 | 0.0002*** |
| Variables | Coefficient | Std. err | t-statistic | P-value |
|---|---|---|---|---|
| lnRE | 0.020549 | 0.003877 | 5.300566 | 0.0001*** |
| lnFD | 0.011651 | 0.008910 | 1.307549 | 0.2107 |
| LnFD(-1) | 0.037080 | 0.007493 | 4.948363 | 0.0002*** |
| lnPoPG | 0.015751 | 0.009486 | 1.660519 | 0.1176 |
| LnPoPG(-1) | 0.074021 | 0.011615 | 6.372838 | 0.0000*** |
| lnGDPPC | 1.201628 | 0.114179 | 10.52405 | 0.0000*** |
| LnGDPPC(-1) | 0.193472 | 0.093596 | 2.067106 | 0.0564* |
| ECM | -0.894588 | 0.054699 | -16.35483 | 0.0000*** |
| Test | F-statistic | P-value |
|---|---|---|
| Breusch-Pagan-Godfrey test | 0.8516 | 0.6156 |
| Breusch-Godfrey LM test | 0.2389 | 0.7909 |
| Jarque-Bera | P-value | |
| Normality | 0.9003 | 0.6375 |
| T-statistic | P-value (5%) | |
| Recursive sum test (CUSUM) | 0.2894 | 0.9479 |
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