Investigation of the causal relationships between combustible renewables and waste consumption and CO2 emissions in the case of Tunisian maritime and rail transport

This study investigates the dynamic causal links between carbon dioxide (CO2) emissions, real Gross Domestic Product (GDP), combustible renewables and waste consumption, and maritime and rail transport in Tunisia spanning the period 1980-2011. The autoregressive distributed lag (ARDL) approach and Granger causality tests are employed to examine the short- and long-run relationships between variables. The empirical results suggest a bidirectional short-run causality between CO2 emissions and maritime transport, and a unidirectional causality running from real GDP, combustible renewables and waste consumption, rail transport to CO2 emissions. The long-run estimates reveal that real GDP contributes to the decrease of CO2 emissions, while combustible renewables and waste consumption and maritime and rail transport have a positive impact on emissions. Our policy recommendation is that Tunisia should use more combustible renewables and waste energy and increase the number of passenger's rail and maritime transport in order to motivate economic activities. However, the level of renewables energy required to reduce CO2 emissions caused by transport sector is still very weak.