Investigation of greenhouse gas emissions originated from public transportation: The case of Ankara

Human induced activities have been increasing the atmospheric abundance of greenhouse gases at an alarming level since pre-industrial times, eventuating in global warming by means of increasing the heat-trapping abilities of the greenhouse gases. Advanced climate models project that global temperature change will exceed 1.5 degrees Celsius at the end of the 21th Century, whereafter the adverse effects of the global warming will be unavoidable. Hence, reducing the atmospheric abundance of the greenhouse gases is of vital importance. Transportation sector is the second largest contributor of the Turkish anthropogenic greenhouse gases with its dominant source being road transportation. In Turkey, road transportation is heavily dependent on individually-owned automobiles. Greater use of public transportation will reduce excessive automobile dependency and greenhouse gas emissions, also providing economic and social benefits. Incidental to both international and domestic regulations, the annual national greenhouse gas inventory covering the Turkish anthropogenic greenhouse gases are being reported adopting the IPCC methodology. The national inventory utilizes fuel sold method in emission calculations from transportation sector. In this thesis, direct greenhouse gas emissions originated from the EGO public transport buses are analyzed with both the highest and the current tier approaches used in the national inventory adapting the IPCC methodology. It is observed that, current approach used estimated emissions in carbon dioxide equivalent ninety five percent less than the highest tier approaches utilized in this thesis. Altering the fuel use habits and vehicle fleet expansion compared to the current trend, hundred and thirty one kilotons of emissions in carbon dioxide equivalent will be avoided and 88,843,822 TL will be saved in a period of next ten years. Keywords: Direct greenhouse gas emissions, IPCC methodology, tier approaches, emission factors.