| Studies | Countries | Methodologies | Results |
| Halicioglu (2009) | Turkey | Granger causality, ARDL | GDP----En |
| Zhang & Chang (2009c) | China | Granger causality, VECM | GDP ® En |
| Apergis & Payne (2009c) | 6 Central American countries | Panel vector error correction model | En GDP in the short run |
| Apergis & Payne (2009b) | 11 independent common wealth countries | Panel cointegration error correction model | En GDP In the short run |
| Saboori & al (2012) | Malaysia | EKC hypothesis | CO2 ® GDP In the long run |
| Lotfalipour et al. (2010) | Iran | Toda-Yamamoto method | GDP ® CO2 In the long run |
| Chang (2008) | China | Multivariate cointegration, vector error correction model | GDP CO2 En GDP En®CO2 |
| Fodha and Zaghdoud (2010) | Tunisia | Granger causality based on ECM | GDP® CO2 |
| Ang (2008) | Malaysia | Granger causality | GDP CO2 |
| Richmond & Kauffman (2006) | 20 developped countries | Cointegration test | En ® CO2 GDP ® CO2 |
| Ozturk & Acaravci (2013) | Turkey | Granger causality ARDL cointegration | EC ≠ GDP CO2 ≠ GDP |
| Pao & al (2011) | Russia | Granger causality VECM, cointegration | GDP CO2 EC GDP EC CO2 |