Transport infrastructure and CO2 emissions in the OECD over the long run

A gap in the transportation-environment literature is the absence of studies analysing the effect of transport infrastructure on carbon dioxide (CO2) emissions, controlling for other factors correlated with CO2 emissions. We address this gap by providing parametric and non-parametric estimates of the effect of transport infrastructure on CO2 emissions for a panel of OECD countries over a period of almost 150 years. We also examine economic growth and population as channels through which transport infrastructure influences CO2 emissions. Our point estimates suggest that a 1% increase in transport infrastructure is associated with an increase in CO2 emissions of about 0.4%, although dependent on the long-run estimator used. Our non-parametric estimates suggest a time-varying relationship between transport infrastructure and CO2 emissions, which was positive during the first wave of globalisation, World War II and for most of the period since 1950. We find that economic growth and population mediate the transport infrastructure CO2 emissions relationship.