Table 3.
Unit root test results for level and first differences, first and second-generation, by a panel of countries: EU 27, EU 15, and EU 12, with and without a trend.
| Independent Variables | Unit Root (First Generation) Panel EU 27 Countries | Unit Root (First Generation) Panel EU 15 Countries | Unit Root (First Generation) Panel EU 12 Countries | |||
| Level | Without T | With Trend | Without T | With Trend | Without T | With Trend |
| GHG pc/Area | 18.619 | 57.391 | 11.626 | 31.145 | 6.993 | 26.246 |
| CO2 pc/Area | 27.061 | 62.435 | 18.225 | 41.148 ** | 8.806 | 21.237 |
| CH4 pc/Area | 6.198 | 304.885 *** | 2.613 | 163.794 *** | 3.585 | 141.091 *** |
| N2O pc/Area | 34.175 | 108.859 *** | 18.768 | 39.911 ** | 15.407 | 68.948 *** |
| GDP pc/Area | 7.16 | 353.888 *** | 6.194 | 187.396 *** | 0.966 | 166.492 *** |
| GDPpc^2/Area | 9.338 | 285.478 *** | 7.37 | 124.259 *** | 1.967 | 161.218 *** |
| Edu pc/Area | 65.694 | 45.328 | 25.932 | 18.954 | 39.763 *** | 26.774 |
| Euse pc/Area | 42.878 | 67.337 ** | 18.648 | 42.211 ** | 24.23 | 25.126 ** |
| Elect pc/Area | 53.353 | 44.12 | 21.634 | 25.518 ** | 31.72 | 18.602 |
| 1st Difference | ||||||
| GHG pc/Area | 48.508 | 103.455 *** | 39.335 | 37.261 | 9.174 | 66.194 *** |
| CO2 pc/Area | 45.173 | 104.912 *** | 32.934 | 50.328 ** | 12.239 | 54.584 ** |
| CH4 pc/Area | 168.220 *** | 164.549 *** | 154.304 *** | 70.429 *** | 13.916 | 94.120 *** |
| N2O pc/Area | 130.955 *** | 172.838 *** | 122.939 *** | 147.36 *** | 8.016 | 25.474 ** |
| GDP pc/Area | 108.255 *** | 215.946 *** | 104.53 *** | 128.54 *** | 3.667 | 87.405 *** |
| GDPpc^2/Area | 126.258 *** | 301.138 *** | 116.719 *** | 158.052 *** | 9.539 | 143.086 *** |
| Edu pc/Area | 50.097 | 73.506 ** | 34.202 | 23.155 | 16.077 | 50.351 *** |
| Euse pc/Area | 66.048 | 80.186 ** | 24.21 | 36.954 | 41.838 ** | 43.231 *** |
| Elect pc/Area | 149.773 *** | 134.525 *** | 21.07 | 23.135 | 128.702 *** | 111.386 *** |
|
CIPS (2nd Generation)
Panel EU 27 Countries |
CIPS (2nd Generation)
Panel EU 15 Countries |
CIPS (2nd Generation)
Panel EU 12 Countries |
||||
| Level | Without T | With Trend | Without T | With Trend | Without T | With Trend |
| GHG pc/Area | −1.413 ** | 1.779 | −1.678 ** | 0.216 | −1.536 ** | 1.029 |
| CO2 pc/Area | −1.710 ** | 1.255 | −1.087 | 0.136 | −0.789 | 1.234 |
| CH4 pc/Area | 1.32 | 2.578 | 1.858 | 2.337 | 0.403 | 0.987 |
| N2O pc/Area | −5.372 *** | −3.277 *** | −3.435 *** | −0.547 | −4.787 *** | −4.099 *** |
| GDP pc/Area | 1.527 | 2.042 | 2.424 | 2.1 | −0.118 | 0.533 |
| GDPpc^2/Area | 1.22 | 4.757 | 3.318 | 4.358 | 0.487 | 2.713 |
| Edu pc/Area | 0.8 | 1.9229 | 0.367 | 1.693 | 0.556 | 0.671 |
| Euse pc/Area | −4.983 *** | −1.857 *** | −4.135 *** | −1.761 ** | −3.042 *** | −0.995 |
| Elect pc/Area | −6.187 *** | −3.502 *** | −6.431 *** | −4.170 *** | −2.401 *** | −0.37 |
| 1st Difference | ||||||
| GHG pc/Area | −0.851 | 4.223 | −0.562 | 1.87 | −2.344 *** | 1.984 |
| CO2 pc/Area | −1.923 ** | 2.82 | −2.098 ** | 0.721 | −2.213 ** | 1.172 |
| CH4 pc/Area | 0.057 | 2.361 | −18.59 ** | 1.743 | −3.282 ** | −5.008 *** |
| N2O pc/Area | −2.476 *** | −2.515 *** | 0.229 | 0.361 | −3.427 *** | −3.941 *** |
| GDP pc/Area | −2.633 *** | 1.601 | −3.476 *** | 1.125 | −2.008 ** | 1.055 |
| GDPpc^2/Area | −3.075 *** | 1.932 | −1.470 ** | 2.209 | −0.758 ** | 0.33 |
| Edu pc/Area | 1.219 | 2.28 | 1.739 ** | 2.52 | 2.448 | −0.603 |
| Euse pc/Area | −3.954 *** | −3.380 *** | −2.905 *** | −0.579 | −4.619 *** | −2.985 *** |
| Elect pc/Area | −7.805 *** | −7.364 *** | −4.964 *** | −4.760 *** | −5.060 *** | −4.565 *** |
Notes: **, *** represents statistically significant at 5% and 1%, respectively. The volume of emissions of carbon per capita (CO2), emissions of methanol per capita (CH4), and emissions of nitrous oxide per capita (N2O). T stands for trend.