Authors | Country | Period | Methodology | Findings |
| 37 African countries | 1995-2017 | PMG | URB has no significant effect on CO2 |
| 29 African countries | 1970-2019 | CS-ARDL | URB increases EF |
| Saudi Arabia | 1990-2015 | QR | URB increases CO2 |
| ASEAN countries | 1995-2018 | CS-ARDL, AMG, CCEMG | URB increases GHG |
| Pakistan | 1980-2018 | OLS | URB increases CO2 |
| Ghana | 1971-2018 | ARDL | URB decreases CO2 |
| China | 1995-2020 | PMG | URB has no significant effect on CO2 |
| West Africa | 1980-2017 | PMG, AMG | URB increases EF |
| Kenya | 1971-2014 | ARDL | URB decreases CO2 |
| Bangladesh | 1980-2020 | ARDL | URB increases CO2 |
| Türkiye | 1970-2020 | FARDL | URB increases CO2 |
| 5 Asian countries | 1972-2021 | CS-ARDL, AMG, MG, CCEMG | URB increases CO2 |
| China | 1970-2021 | ARDL | URB increases CO2 |
| Somalia | 1985-2016 | ARDL, KRLS | URB increases CO2 |
| 10 nations | 1990-2019 | PMG | URB increases CO2 |
| 5 African countries | 1990-2019 | FE, RE, FGLS, AGM | URB decreases CO2 |
| 95 countries | 1990-2018 | AMG, CCEMG, DCCE | URB increases EF |
| 7 Asian countries | 1990-2018 | CS-ARDL, PMG | URB increases CO2 |
| 16 West African countries | 2005-2018 | GMM, OLS, FE, RE | URB increases CO2 |
| China | 1998-2019 | FE, RE | URB reduces NDVI |
| Nigeria | 1970-2017 | ARDL | URB decreases EF |
| 31 African countries | 1990-2019 | FMOLS, PMG, AMG | URB has an inverted U-shaped impact on CO2 and a U-shaped impact on EF |
| 54 African Union countries | 1996-2019 | QR, FMOLS | URB increases CO2 |
| 16 West African countries | 1990-2018 | AMG, CCEMG | URB increases CO2 |
| 28 EU countries | 2000-2018 | FMOLS, MG, CCEMG, AMG | URB mitigates CO2 |
| Saudi Arabia | 1971-2019 | ARDL | URB causes CO2 |
| 48 African countries | 1980-2016 | QR | URB increases CO2 |
| NICs | 1990-2017 | MG, PMG, AMG, CCEMG | URB increases EF |
| BRICS | 1972-2021 | CS-ARDL | URB increases CO2 |
| 156 countries |
| Threshold regression | URB increases CO2 and EF |
| 30 nations | 1992-2016 | AMG, CCE | URB increases EF |
| Latin America | 1980-2017 | FMOLS, DOLS | URB increases CO2 |
| 5 African countries | 1990-2019 | CS-ARDL | URB has no significant effect on EF |
| 23 African countries | 1960-2016 | CUP-FM, CUP-BC | URB increases EF |
| 34 African countries | 1990-2016 | QR | URB increases CO2 |
| Bangladesh | 1972-2016 | ARDL | URB increases CO2 |
| 5 Asian countries | 1995-2014 | DOLS, FMOLS | URB increases CO2 |
| GCC | 1990-2018 | CS-ARDL | URB increases CO2 |
| 16 West African countries | 1990-2018 | Driscoll-Kraay regression | URB increases CO2 |
| Indonesia | 1971-2014 | ARDL | URB increases EF |
| Latin American and Caribbean countries | 1990-2017 | AMG, CCEMG | URB increases CO2 |
| 10 countries | 1995-2016 | CUP-FM, CUP-BC | URB reduces EF |
| Malaysia | 1978-2018 | ARDL | URB increases CO2 |
| E7 economies | 1990-2016 | AMG, FMOLS, DOLS | URB increases CO2 and EF |
| 5 Asian countries | 1991-2017 | ARDL | URB increases EF, but it moderates the impact of informal economy on EF |
| 22 countries | 1980-2010 | MG, DOLS, FMOLS | URB has insignificant impact on CO2 |
| BRICS | 1998-2016 | FMOLS | URB reduces CO2 |
| Bangladesh | 1973-2014 | ARDL | URB increases CO2 |
| India | 1971-2014 | ARDL | URB reduces CO2 |
| Burkina Faso | 1980-2017 | ARDL | URB increases DF |
| BRICS | 1993-2018 | GMM | URB increases CO2 |
| Pakistan | 1980-2018 | ARDL | URB decreases EF |
| 8 Asian countries | 1982-2017 | FMOLS | URB increases CO2 |
| 19 African countries | 1980-2011 | IV-GMM | URB decreases CO2 |
| 6 island countries | 1995-2014 | FMOLS, PMG | URB reduces CO2 |
| 12 African countries | 1980-2014 | PMG | URB increases CO2 |
| G7 countries | 1971-2014 | CUP-FM, CUP-BC | URB increases EF |
| China | 1970-2016 | ARDL | URB increases EF |
| Nigeria | 1970-2017 | ARDL | URB reduces CO2 |
| 13 Asian countries | 1985-2019 | FMOLS | URB mitigates CO2 |
| SAARC | 1994-2013 | FE | URB has a U-shaped impact on CO2 |
| 9 Asian countries | 1980-2017 | FE | URB increases CO2 |
| African countries | 1980-2014 | PMG | URB increases CO2 |
| BRICS | 1992-2016 | FMOLS, DOLS | URB decreases EF |
| Ghana | 1971-2016 | ARDL | URB increases EF |
| African countries | 2005-2019 | PSTR | URB reduces CO2 |
| 65 countries | 2000-2016 | QR, 2TLS | URB has an inverted U-shaped impact on CO2 |
| Nigeria | 1980-2016 | ARDL | URB increases CO2 |
| 6 ASEAN | 1990-2016 | AMG | URB has no significant effect on EF |
| MENA countries | 1990-2016 | AMG | URB increases CO2 |
| 6 countries | 1990-2014 | AMG | URB increases EF |
| 11 Asian countries | 1995-2018 | FMOLS, DOLS | URB increases CO2 |
| Australia and Canada | 1960-2015 | ARDL | URB increases CO2 |
| Nigeria | 1974-2015 | ARDL | URB reduces CO2 |
| China | 2003-2017 | Dynamic spatial panel | URB reduces CO2 |
| 46 African countries | 2000-2015 | GMM | URB increases CO2 |
| 28 African countries | 1980-2014 | FOLS, GMM | URB mitigates CO2 |
| Pakistan | 1972-2014 | ARDL | URB triggers CO2 |
| 59 countries | 1990-2016 | Driscoll-Kraay regression | URB increases EF |
| 11 countries | 1971-2014 | CCEMG | URB increases EF |
| 4 countries | 1971-2013 | ARDL | URB increases EF |
| Sri Lanka | 1978-2014 | ARDL, FMOLS | URB reduces CO2 |
| Pakistan | 1971-2016 | ARDL | URB reduces CO2 |
| 18 Asian countries | 1980-2014 | PMG | URB increases CO2 |
| South Africa | 1965-2014 | ARDL, FMOLS, DOLS, CCR | URB mitigates EF |
| China | 1996-2015 | FMOLS | URB increases CO2 |
| 55 middle-income countries | 1992-2012 | PMG | URB reduces CO2 |
| ASEAN-5 | 1971-2014 | FE, RE | URB increases CO2 |
| 100 countries | 1980-2017 | DOLS | URB increases CO2 |
| 44 African countries | 1984-2016 | MG, PMG, CCEMG, AMG | URB increases CO2 |
| South Africa | 1980-2017 | ARDL | URB increases CO2 |
| 13 Asian countries | 1980-2010 | MG, PMG, AMG | URB has no significant effect on CO2 |
| 14 African countries | 1990-2014 | AMG | URB increases EF |
| 26 African countries | 1985-2011 | GMM | URB increases CO2 |
| 49 African countries | 1990-2010 | FE | URB reduces CO2 |
| 34 African countries | 1995-2015 | GMM | URB increases CO2 |
| Ghana | 1971-2013 | FMOLS | URB increases CO2 |
| China | 1970-2015 | ARDL | URB increases CO2 |
| Türkiye | 1974-2014 | ARDL, FMOLS | URB triggers CO2 |
| Vietnam | 1985-2015 | ARDL | URB has no significant effect on CO2 |
| Saudi Arabia | 1971-2014 | ARDL | URB reduces CO2 |
| Singapore | 1970-2015 | ARDL | URB mitigates CO2 |
| Senegal | 1980-2011 | NIPALS | URB decreases CO2 |
| Qatar | 1970-2015 | MS | URB increases EF |
| 15 MENA countries | 1975-2007 | DOLS, FMOLS | URB reduces EF |
| 17 Asian nations | 1980-2012 | DOLS, FMOLS | URB has insignificant impact on CO2 |
| Malaysia | 1971-2015 | ARDL | URB has an inverted U-shaped impact on CO2 |
| 19 emerging nations | 1990-2013 | GMM | URB reduces CO2 |
| 141 countries | 1961-2011 | FE | URB has an inverted U-shaped impact on CO2 |
| 45 African countries | 1990-2010 | PMG | URB increases CO2 |
| Nigeria | 1971-2011 | ARDL | URB has no significant effect on CO2 |
| India, Bangladesh, Sri Lanka, and Pakistan | 1982-2013 | OLS | URB decreases CO2 in Bangladesh and India, UBR increases CO2 in Sri Lanka. URB has no significant effect on CO2 in Pakistan |
| 10 European countries | 1991-2011 | DOLS, FMOLS | URB reduces CO2 |
| USA | 1960-2010 | ARDL | URB increases CO2 |
| 28 Chinese provinces | 1996-2012 | GMM, MG, PMG, DFE | URB increases CO2, waste water, and waste solid |
| 5 African countries |
| FMOLS | URB reduces CO2 |
| Malaysia | 1997-2011 | ARDL | URB has a U-shaped impact on CO2 |
| China | 1995-2011 | MG, PMG, DFE | URB increases CO2 |
| 5 Asian countries | 1983-2013 | OLS | URB increases CO2 |
| ASEAN | 1980-2009 | FMOLS | URB increases CO2 |
| BRICS | 1985-2014 | FMOLS | URB increases CO2 |
| China | 1979-2013 | TR | URB increases CO2 |
| 14 MENA nations | 1996-2012 | FMOLS | URB increases EF |
| 93 countries | 1980-2008 | FE, GMM | URB aggravates EF |
| 129 countries | 1980-2011 | DOLS | URB increases CO2 in lower-middle, upper-middle and high-income countries while no effect in low-income countries. |
| 45 African countries | 1980-2009 |
| URB has no significant effect on CO2 |
| 19 African countries | 1985-2010 | VAR | URB increases CO2 |
| Cote d’Ivoire | 1970-2010 | ARDL | URB reduces CO2 |
| 73 countries | 1971-2010 | FE, RE | URB reduces CO2 in middle-/high-income nations, and increases CO2 in low-income, middle-/low-income and high-income nations |
| OECD | 1960-2010 | FE | URB has an inverted U-shaped impact on CO2 |
| 30 China 30 provinces | 1990-2011 | Nonparametric additive regression | URB has an inverted U-shaped impact on CO2 in eastern region, a positive U-shaped effect in central region, and insignificant nexus in western region |
| Africa | 1960-2010 | ARDL | URB has no significant effect on CO2 |
| 16 countries | 1971-2009 | MG, AMG, CCEMG | URB has no significant effect on CO2 |
| United Arab Emirates | 1975-2011 | ARDL | URB increases CO2 |
| MENA | 1980-2009 | DOLS | URB triggers CO2 |