This indicator shows greenhouse gas (GHG) emissions from transport in Slovenia from the base year 1986 onwards by transport mode in Slovenia and in European countries in the period 1990–2014. Total emissions are subdivided into road, air and rail transport. Maritime and inland waterway transport emissions are included in road transport, as there is no separate data available on fuel consumption for this purpose. Emissions from international bunkers are not included and are not considered to be national emissions.

Greenhouse gas emissions include carbon dioxide (CO₂), methane (CH₄), dinitrous oxide (N₂O), hydrofluorocarbons (HFC), perfluorocarbons (PFC) and sulphur hexafluoride (SF₆). For comparability purposes, the GHG amounts are calculated as CO₂ equivalent, taking into account the differences between the global warming potential of individual gases. Emissions from transport relate to the first three of the above-mentioned gases.

Mitigation of climate change is the biggest environmental development challenge facing humanity. Scientific results show that there is a connection between GHG emissions (CO₂, CH₄, N₂O and F-gases) and atmospheric temperature. As the amount of anthropogenic greenhouse gases in the atmosphere is intensively increasing due to increasing emissions, particularly as a result of fuel consumption, there is a high probability of a temperature increase in the future. This would strongly influence life on Earth. Therefore, a campaign has been commenced at the international level, the objective of which is to reduce GHG emissions to values that would have an acceptable impact on the environment. The Kyoto Protocol stipulates emissions for the period 2008–2012 with regard to emissions in the base year, which are defined for Slovenia as the sum of CO₂, CH₄ and N₂O emissions in 1986 (the base year for developed countries is 1990) and F-gases in 1995. The limitation of GHG emissions in Slovenia obtained a legal framework and specific objectives with the adoption of the Act Ratifying the Kyoto Protocol to the United Nations Framework Convention on Climate Change (Official Gazette of the Republic of Slovenia, No. 60/2002).

At the 12th conference meeting of the contracting parties in 2006, negotiations on new objectives for the period after 2012 began. The leading role was taken over by the European Union, which adopted an objective in 2007 to reduce GHG emissions by 20% (or 30 %) by 2020 with regard to the base year. A 20% reduction in emissions is required if the international agreement on the reduction of GHG emissions is not adopted and a 30% reduction if it is.

According to the data obtained by the Slovenian Environment Agency, the largest share of GHG is contributed by transport (32% in 2014), followed by the energy sector (27%). Transport GHG emissions almost tripled in the period 1986-2014. Road transport emissions increased by 173% and air transport emissions by 140%; on the other hand, rail transport emissions decreased by 41%. In the structure of greenhouse gasses in the considered period, CO₂ emissions increased the most (169%), followed by N₂O emissions (83%), while CH₄ emissions decreased by 69%.

Road transport is the largest source of transport emissions. In 2014, it contributed 99.1% of all transport emissions. The number of road motor vehicles as well as the power and capacity of their engines has been constantly increasing in Slovenia, while the specific use of new vehicles has been in slow decline. The development of infrastructure, especially in urban areas, cannot follow such growth; therefore, congestion has been becoming more frequent. In recent years, the increase in road freight (especially transit) transport through Slovenia is also a major problem. The share of transit freight transport emissions in 2014 was estimated to be 35.5%, while other emissions are caused by passenger transport (personal transport 63.2%, bus transport 1.4%).

According to the data compiled by the European Environment Agency, GHG emissions from transport (excluding international air and maritime transport) in the EU-28 increased by 13% in the period 1990–2014. With air and maritime transport included, GHG emissions decreased in the period 1990–2014. The decrease in recent years is probably a consequence of reduced freight transport and higher fuel prices, as well as the economic recession. Although EU maritime transport emissions decreased, additional measures will need to be adopted in the EU to achieve a 68% reduction of emissions from transport by 2050 compared to 1990 values (TERM, 2016).

According to the growth of emissions, Slovenia was ranked fifth among 33 European Environment Agency member countries in 2014. In older Member States, growth in emissions has stabilised in recent years, while in the same period, growth has been significant in new Member States. Road and air transport contributed to this growth; GHG emissions from international air transport and maritime transport are also increasing rapidly, but these emissions are not included in the GHG emission totals relevant for the Kyoto targets.

For the fulfilment of its Kyoto Protocol commitments, in 2009, the Government of the Republic of Slovenia adopted an amended and supplemented Operational Programme to Reduce GHG Emissions. According to the last report to the Government on the implementation of the Operational Programme for 2011, lower transport emissions in recent years are a result of a considerable reduction in international trade flows, meaning the volume of road freight transport. The adaptation of excise duties, meaning that retail fuel prices remained comparable to prices in neighbouring countries, was also an important factor. Despite introducing urgent sustainable transport policy measures, Slovenia still failed to meet its Kyoto commitments. Substantial funds for investments in railway infrastructure were secured at the beginning of 2010 to help meet these requirements. In the same year, activities in the field of public passenger transport also intensified. Although support for the development and introduction of low-carbon technologies has increased (new competitive and development centres, a programme to support the introduction of electric vehicles), this area, as a whole, has not yet been given priority in research and development policy.

In 2014, the Government adopted the new Operational Programme to Reduce Greenhouse Gas Emissions by 2020. It sets a long-term target to reduce emissions from the transport sector by at least 50% by 2050 and 9% by 2020 compared to 2008 values. In order to meet these goals, implementation of various measures is planned, e.g. introduction of low-carbon technologies, sustainable transport and ensuring equal or better quality of life with fewer kilometres travelled. Until 2020, the measures will primarily be focused on the improvement of efficiency of vehicles, support of technologies and fuels with lower CO₂ emissions and improvement of the quality and accessibility of public transport in order to intensify its use and optimise transport.