Fig. 12

a Quantile regression of the CO₂ emission vs ln(GDP) when the country’s E.C. is 2980.96 kilowatts at τ=0.97.Q _R −solid blue, Q _W −dashed blue, μ _LS −red solid line. b Quantile regression of the CO₂ emission vs ln(E.C.) when the country’s GDP is $13,359.73 at τ=0.97. Q _R −solid blue, Q _W −dashed blue, μ _LS −red solid line. c 3D scatter plot with Q _R −red and Q _W −green for τ=0.97