A way forward in reducing carbon emissions in environmentally friendly countries: the role of green growth and environmental taxes

Figures & data

Table 1. The results of the panel unit root test.

	Levels		First differences
	Breitung	CADF	Breitung	CADF
CO2	–1.56	–2.06	–5.10***	–2.59***
GG (GG^2)	–1.44	–1.76	–5.49***	–4.29***
ETAX	0.02	–1.42	–3.11***	–2.28***
REN	0.68	–1.87	–5.19***	–2.51***
EI	0.63	–1.45	–4.72***	–2.67***

*** 1% level of significance.

Source: Authors.

Table 2. The results of the panel cointegration test.

Pedroni cointegration		Westerlund cointegration
	Statistics		Statistics
Modified Phillips–Perron t	6.64***
Phillips–Perron t	2.68***	Variance ratio	7.09***
Augmented Dickey–Fuller t	3.69***

*** 1% level of significance.

Source: Authors.

Table 3. Koenker (2004)’s quantile results.

	OLS	0.05	0.10	0.25	0.50	0.75	0.90	0.95
GG	–1.23*** (0.333)	–0.48 (0.340)	–0.56* (0.320)	–0.91** (0.375)	–0.86 (0.669)	–0.64* (0.381)	–0.82* (0.475)	–0.60 (0.520)
GG^2	–0.17*** (0.053)	–0.05 (0.054)	–0.06 (0.051)	–0.10* (0.060)	–0.12 (0.107)	–0.10* (0.061)	–0.13* (0.076)	–0.11 (0.083)
ETAX	–1.21*** (0.161)	–0.62*** (0.163)	–0.79*** (0.154)	–1.15*** (0.181)	–1.09*** (0.322)	–2.15*** (0.183)	–2.51*** (0.228)	–2.48*** (0.250)
REN	–0.55*** (0.042)	–0.22*** (0.043)	–0.21*** (0.040)	–0.27*** (0.047)	–0.61*** (0.084)	–0.94*** (0.048)	–0.87*** (0.060)	–0.86*** (0.065)
EI	–1.41*** (0.116)	–1.77*** (0.118)	–1.67*** (0.111)	–1.62*** (0.130)	–0.66*** (0.232)	–0.79*** (0.132)	–1.29*** (0.164)	–1.58*** (0.180)
Cons.	8.38*** (0.526)	6.32*** (0.535)	6.57*** (0.504)	7.37*** (0.590)	7.79*** (1.052)	11.73*** (0.599)	13.38*** (0.746)	14.25*** (0.817)

* , ^**, ^***Represent 10%, 5% and 1% level of significances, respectively.

Source: Authors.

Table 4. Powell (2016)’s quantile results.

	OLS	0.05	0.10	0.25	0.50	0.75	0.90	0.95
GG	–1.23*** (0.333)	–0.44 (4.892)	–0.56** (0.274)	–0.91*** (0.349)	–0.86** (0.377)	–0.66** (0.324)	–0.83** (0.403)	–0.60* (0.351)
GG^2	–0.17*** (0.053)	–0.07 (1.649)	–0.06* (0.034)	–0.11** (0.043)	–0.12*** (0.046)	–0.10** (0.046)	–0.13*** (0.050)	–0.11** (0.043)
ETAX	–1.21*** (0.161)	–0.61*** (0.093)	–0.79*** (0.145)	–1.15*** (0.186)	–1.09** (0.473)	–2.10*** (0.251)	–2.04*** (0.434)	–2.40*** (0.562)
REN	–0.55*** (0.042)	–0.23*** (0.038)	–0.21*** (0.036)	–0.27*** (0.052)	–0.61*** (0.102)	–0.93*** (0.066)	–0.88*** (0.113	–0.88*** (0.099)
EI	–1.41*** (0.116)	–1.79*** (0.103)	–1.68*** (0.067)	–1.63*** (0.079)	–0.66** (0.312)	–0.79*** (0.223)	–1.29*** (0.375)	–1.58*** (0.304)
Cons.	8.38*** (0.526)	6.44* (3.515)	6.57*** (0.433)	7.37*** (0.597)	7.79*** (1.412)	11.57*** (0.728)	12.46*** (0.973)	14.10*** (1.163)

* , ^**, ^***Represent 10%, 5% and 1% level of significances, respectively.

Source: Authors.

Figure 1. Results from quantile regression.

Source: Authors.

Koenker, R. (2004). Quantile regression for longitudinal data. Journal of Multivariate Analysis, 91(1), 74–89. https://doi.org/10.1016/j.jmva.2004.05.006

 Web of Science ®Google Scholar

Powell, D. (2016). Quantile regression with nonadditive fixed effects. https://ideas.repec.org/c/boc/bocode/s458157.html

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Data availability statement

The data are available upon request.