Climate

Figure 10 shows direct EU-27 GHG emissions trends over time for different modes of transport, including emissions from international bunkers; it also reports projections until 2050. Upstream emissions, associated with, for example, electricity generation and fossil fuel extraction and manufacturing, as well as downstream emissions, from, for example, the end-of-life and recycling of vehicles and their components, are not included in the following figures.

GHG emissions from transport, expressed in MtCO₂e, peaked in 2007, at approximately 1,142 MtCO₂e. They then decreased following the 2007-2008 financial crisis (EEA, 2010) before reacing a new peak in 2019, at 1,102 MtCO₂e. Emissions then decreased sharply in 2020, down to 898 MtCO₂e, due to the COVID-19 pandemic, a drop of 18.5% compared to the previous year. They increased again in 2022 (16.2%), rising to approximately 1044 MtCO₂e.

The share of transport emission on the overall EU-27 GHG emissions increased steadily in the 1990-2019 period, from 16.5% in 1990 to 28.6% in 2019. In 2022, transport accounted for approximately 28.9% of all EU-27 GHG emissions. Overall, in 2022 transport GHG emissions were 25.9% higher than in 1990.

Projected emissions in Figure 10 correspond to those reported by Member States under Article 18 of the Regulation on the Governance of the Energy Union, whereby each Member State developed an integrated national energy and climate plan (EU, 2018b), according to the ‘with additional measures’ (WAM) scenario. This, as further explained in Annex, includes not only all the policies and measures that were adopted or implemented at the time of reporting, but also all planned measures (which may not reflect the lastest developments at EU level). These projections indicate that, in 2050, the transport sector in the EU-27 will still be emitting 656 MtCO₂e, with road transport being the major contributor (51.9%), followed by navigation (24.8%), aviation (22.2%) and rail (0.5%). The relative contribution of transport (including international bunkers) to overall GHG emissions in the EU-27 is expected to grow from 28.9% in 2022 to 31.1% in 2050.

Figure 10. EU-27 GHG emissions as reported to the to the United Nations Framework Convention on Climate Change (UNFCCC) and to the EU Greenhouse Gas Monitoring Mechanism

1Absolute (MtCO2e)2Shares — transport (%)3Shares — total (%)

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Road transport

EU-27 GHG emissions from road transport are almost entirely due to light- and heavy-duty vehicles; powered two-wheelers and other road transport modes are responsible for less than 1% of overall transport emissions.

In 2022, emissions from light-duty vehicles (i.e. cars and vans in Figure 10) reached approximately 544 MtCO₂e and accounted for about 52.1% of all transport GHG emissions. This share has remained essentially constant over the last 32 years, with an average of 53% and standard deviation of 1.1%. Overall, GHG emissions from light-duty vehicles had increased by 21.2% in 2022 compared to 1990. The improved energy efficiency of new vehicles and the increased use of biofuels, both promoted by EU legislation (EU, 2024c, EU, 1998, EU, 2023a), have been more than offset by the increase in demand for passenger transport and an increase in the share of passenger car transport, as discussed in the section on passenger transport activity, Figure 1. This had led to higher GHG emissions from passenger cars in 2019 compared to 2000 (EEA, 2022b).

Recently, more stringent CO₂ emission performance standards for new cars and vans have been approved. Notably, this includes an EU-27 fleet-wide CO₂ emission target for both new cars and vans of 100% reduction, meaning 0 gCO₂/km at the tailpipe, by 2035. The Commission is also required to take legislative initiatives so that new vehicles with internal combustion engines may still be type-approved and sold after 2035, provided they run solely and permanently on CO₂ neutral fuels of non-biological origin. This will require a solid monitoring and enforcing mechanism to avoid any possibility of tampering and deliberate non-compliance with the standard.

Irrespectively of the additional legal initiative mentioned above, the emissions standards only cover the emissions of CO₂ at the tailpipe, meaning that other GHGs such as CH₄ and N₂O are not currently considered. Internal combustion engines using carbon-neutral fuels or hydrogen could potentially emit substantial quantities of climate forcing gases such as N₂O. This is due to the way NOx aftertreatment systems operate, as will be extensively discussed later in the dedicated section on air pollutants (Selleri et al., 2022a, Giechaskiel et al., 2022a, Gioria et al., 2024).

Transport and Environment Report 2022

In addition, the Energy Performance of Buildings Directive has been revised (EU, 2024a); this also aims to strengthen the development of the charging infrastructure for electric vehicles. It includes, for example, provisions on pre-cabling (to enable the installation of charging points at a later stage with minimal effort) for new and renovated buildings and stricter requirements on the number of recharging points which must be available in both residential and non-residential buildings. Moreover, recharging points will have to allow smart charging and, where appropriate, bi-directional charging, supporting vehicle-to-grid integration (EEA, 2023a).

In 2022, heavy-duty vehicles emitted approximately 210 MtCO₂e, representing 20% of GHG emissions from transport. Overall, GHG emissions from heavy-duty vehicles have increased by 29.3% since 1990. Furthermore, heavy-duty vehicles emitted approximately the same amount of GHG as the navigation and aviation sectors combined (both national and international), which totalled 271 MtCO₂e in 2022. The increase in GHG emissions from heavy-duty vehicles in the 1990-2022 period was primarily driven by growth in freight transport activity and by an increase in the share of road freight transport, as discussed in the section on freight transport activity, Figure 3 above. This was only partly offset by lower energy consumption per tonne-km (EEA, 2022b).

In May 2024, CO₂ emission performance standards for new heavy-duty vehicles were further tightened (EU, 2024b). Notably, these include an EU-27 fleet-wide CO₂ emission target of 90% reduction by 2040 and a provision to have all new urban buses with zero CO₂ tailpipe emission by 2035. Also in this case, similarly to the light-duty one, the EC would also be required to take legislative initiatives to allow the possibility of registering heavy-duty vehicles running exclusively on CO₂ neutral fuels. The same concerns already expressed above in relation to similar legislation for light-duty vheicles also apply here.

In 2022, powered two-wheelers (mopeds and motorcycles) accounted for 9 MtCO₂e of GHG emissions, an amount comparable to the one emitted by domestic aviation. Emissions from these modes of transport oscillated in the 1990-2022 period, with an overall increase of 10.7% since 1990. In 2022 they represented 0.9% of the GHG emissions from transport.

Overall, road transport emissions in 2022 totalled approximately 764 MtCO₂e, representing 73.2% of all transport emissions and 21.1% of all EU-27 GHG emissions (including international bunkers). According to the projections, emissions from the road transport sector will reach 596 MtCO₂e in 2030 and 340 MtCO₂e in 2050, corresponding to reductions of 22.0% and 55.4% respectively compared to 2022.

In addition to the measures already discussed, the sector will be covered by a new ETS system, the ETS 2. This will address CO₂ emissions from fuel combustion in buildings, road transport and additional sectors (mainly small industry not covered by the existing EU ETS). This new ‘cap and trade’ system will become operational in 2027 and will be applicable to upstream processes. Thus, fuel suppliers, rather than end users such as households or car users, will be required to purchase and surrender allowances to cover their emissions. The ETS 2 cap will be set to bring emissions down by 42% by 2030 compared to 2005 levels (EC, 2024c).

Waterborne transport

In 2022, combined EU-27 GHG emissions from domestic and international navigation (including inland navigation) reached 149 MtCO₂e, an increase of 19.9% since 1990; this trend has a similar trajectory as that for total transport emissions (Figure 10). In 2022, waterborne transport was responsible for around 14% of total transport emissions, a share that has remained relatively constant over the 1990-2022 period. Also in 2022, international navigation accounted for approximately 7 times the emissions from domestic navigation. It is worth noting that domestic navigation decreased by around 17.6% during the 1990-2022 period, to 18 MtCO₂e. The reduction for the 1990-2019 period, up to but not including the COVID-19 pandemic, was 16.2%.

In 2023, the Monitoring, Reporting and Verification of CO₂ emissions system, commonly known as MRV (Regulation (EU) 2015/757), was amended (EU, 2023d). As a result, from 1st January 2024, shipping companies are required to monitor and report not only their CO₂ emissions but also CH₄ and N₂O emissions that, as we will discuss also later, can be important contributors to the overall GHG emissions from the sector. Moreover, the scope of the regulation will be further expanded (from 2025) to cover smaller general cargo ships between 400 and 5,000 gross tonnage and offshore ships of 400 gross tonnage and above. In addition, starting from 1 January 2024, the EU-ETS will also be applicable to CO₂ emissions from ships of and above 5,000 gross tonnage, calling at or departing from ports in the European Economic Area (EEA), no matter what flag they fly. The system covers 100% of the emissions produced at berth in EEA ports or when travelling within the EEA, together with 50% of the emissions produced by voyages starting or ending outside the EEA. From 2026, emissions of CH₄ and N₂O will also be included (EU, 2023c).

Finally, the Fuel EU Maritime regulation (Regulation (EU) 2023/1805) will apply starting from 1 January 2025, with the exception of Articles 8 (monitoring plan) and 9 (modifications to the monitoring plan) which will apply from 31 August 2024 (EU, 2023f). This regulation aims to increase the uptake of low and zero carbon fuels in maritime transport, by requiring the GHG intensity (measured in gCO₂e/MJ) of energy used on board ships of and above 5,000 gross tonnage calling at EU ports to be reduced progressively. GHG instensity must decrease by at least 2% in 2025 and 6% in 2030, up to 80% by 2050 in five-years increments. Certain exemptions will apply until 2030. Reductions will be estimated from a reference value (91.16 gCO₂e/MJ) calculated based on data reported under MRV (EU, 2023d, EMSA, 2024) for 2020. The regulation also mandates the use of onshore power supply (OPS) or alternative zero-emission technologies while at berth, as further discussed in the section on energy infrastructure.

According to the projections introduced at the start of this section, emissions from the waterborne transport sector are expected to reach 155 MtCO₂e in 2030 and 163 MtCO₂e in 2050, corresponding to variations of 4.4% (0.2%) and 9.6% (5.2%) respectively compared to 2022 (2019).

Aviation

Aviation is the sector which has experienced the largest relative increase in GHG emissions, if the effects of the COVID-19 pandemic are excluded. In 2019, GHG emissions from aviation peaked at around 147 MtCO₂e, representing an increase of approximately 123.4% compared to 1990. This increase was mostly driven by international aviation which emitted 8.9 times more than domestic aviation in 2019. Aviation was responsible for 13% of all transport GHG emissions in 2019, an increase of roughly 5.0 percentage points since 1990. This share dropped to 11.8% in 2020, equivalent to 64 MtCO₂e, as a result of the pandemic. But in 2022 aviation emissions were still 123 MtCO₂e, 92.7% higher again than in 2020, representing an 11.8% share of emissions from the whole transport system.

Notably, CO₂ emissions from aviation within the EEA (with specific provisions for its outermost regions), are covered by the EU ETS. Switzerland has its own system which is however linked to the EU ETS, while the UK system is independent. This means that emissions above the aviation cap need to be compensated for by a reduction in emissions in other sectors of the EU ETS, such that the overall ETS cap is respected (EC, 2024g).

It is worth noting that aviation contributes to global warming also through mechanisms that are not directly related to CO₂ emissions and are normally labelled as non-CO₂ effects. The total average climate impact of aviation has been estimated between two and four times the one associated to CO₂ impact, although the uncertainty associated with the quantification of non-CO₂ effects is higher than those of the CO₂ emissions (Lee et al., 2021). These non-CO₂ effects include, among others, the formation of stable contrails in ice supersaturated regions that can absorb and reflect infrared radiation with an overall warming effect as well as the emission of climate-forcing pollutants. The EU ETS rules for the aviation sector have been revised recently (EU, 2023b); according to the revised Directive, the EC will implement a monitoring, reporting and verification (MRV) system for non-CO₂ effects in aviation from 2025. By 2027, the EC will submit a report based on the MRV. By 2028, if deemed appropriate and after an impact assessment, the EC will produce a proposal to address non-CO2 effects.

In addition to the ETS, in the context of the Fit for 55 policy package (EC, 2021b), the ReFuelEU Aviation regulation (EU, 2023g) aims to gradually increase the uptake of Sustainable Aviation Fuels (SAF) in the aviation sector. These as already mentioned, can reduce GHG emissions from planes of a variable amount, depending on different factors (Watson et al., 2024, Zhao et al., 2021, Uludere Aragon et al., 2023). The regulation requires a progressive increase in the supply of SAF at all EU airports, starting from 2% in 2025 and reaching 70% by 2050. From 2030, 1.2% of the SAF supplied should be synthetic aviation fuel (i.e. 0.07% of aviation fuel supplied at European airports), with this share increasing up to at least 35% in 2050 (i.e. 24.5% of aviation fuel supplied at European airports). In addition, under the revised ETS Directive, additional resources to support the electrification of aviation and actions to reduce overall climate impacts of the sector should be made available. Indeed, the revised ETS Directive commits Member States to use all ETS revenues for climate action, energy transformation and addressing the social challenges of carbon pricing.

According to the projections already introduced, GHG emissions from international and domestic aviation are expected to be around 135 MtCO₂e in 2030 and 146 MtCO₂e in 2050, i.e. variations of 10.1%/-8.3% and 18.6%/-1.2% compared to 2022 or 2019 respectively.

Rail

The rail sector has the lowest absolute GHG emissions of all those shown in Figure 10; it was responsible for approximately 3 MtCO₂e in 2022. This is consistent with the fact that the sector is highly electrified and rail emissions in the GHG emission inventory are only those related to fossil fuel consumption, as already discussed. Notably, diesel consumption in the sector decreased over time, as shown in Figure 7, leading to a 68.1% reduction in direct emissions in the 1990-2019. This occurred despite a 34.9% increase in rail passenger transport activity in 1990-2019 as shown in Figure 1, a stable situation for freight activity, as indicated in Figure 3 and no significant increase in electricity consumption, as illustrated in Figure 7. Overall, the rail sector was responsible for 0.3% of the direct emissions from transport in the EU-27 in 2022.

Methane (CH₄) and nitrous oxide (N₂O) emissions

Having discussed overall GHG emissions in terms of MtCO2e, the following paragraphs will consider the historical and projected emissions of CH₄ and N₂O. CH₄ and N₂O are potent GHG; respectively, they have a global warming potential that is 28 times and 265 times that of CO₂ in a 100-year time frame (Myhre et al., 2013). In 2022, CH₄ and N₂O from transport were responsible for approximately 0.15% and 0.92% of the overall transport GHG emissions and to 0.4% and 5.75% respectively of the overall CH₄ and N₂O emissions in the EU-27, as measured in MtCO₂e.

Furthermore, CH₄ emissions also play a role in air pollution since they contribute to ground level (tropospheric) ozone formation (Fang et al., 2013). Equally, N₂O has been identified in the literature as the most significant anthropogenic contributor to stratospheric ozone layer depletion (Ravishankara et al., 2009). It is important to notice that estimating the emissions of these compounds through the approaches conventionally used in the inventories is not trivial. This problem arises due to several concurring factors. First, there is hardly any emission standard across transport modes, except for the recently approved Euro 7 regulation (EU, 2024d), that regulates the emission of these compounds and requires them to be measured during type-approval and in real-world test. This implies that there is a lack of good quality data when compared to more conventional compounds. Moreover, deriving accurate N₂O emissions through emission factors that depend only on fuel consumption is hardly possible since N₂O mostly forms as a result of processes occurring in the aftertreatment units (Selleri et al., 2021).

Figure 11 indicates that CH₄ emissions from transport fell by 75.6% in the period 1990-2022, to 56.7 Gg (or kiloton, kt). This was mainly due to reduced CH₄ emissions from passenger cars, down from 173.7 Gg and a 74.7% share in 1990 to 24.9 Gg and a 44.0% share in 2022. This decrease can be largely attributed to the evolution of aftertreatment systems. Similar trends and reductions can be seen for other road transport categories over the same period.

Interestingly, powered two-wheelers are a significant source of CH₄ with emissions equal to 8.8 Gg in 2022, i.e. 1.7 times higher than those for heavy-duty vehicles, 9.5 times than those for the whole aviation sector and comparable to those for international navigation. Emissions in the aviation sector were generally stable in the 1990-2019 period at an average of 1 Gg and standard deviation of 0.1 Gg. International aviation emitted 3.1 times more than domestic aviation in 2019.

Navigation is the sector in which CH₄ emissions have increased the most. They reached 14.4 Gg in 2022, an increase of 41.5% compared to 1990, with international navigation emitting approximately 3.2 times more CH₄ than domestic navigation. As discussed in the section on energy, this increase, especially in recent years, was partly due to an increased use of natural gas to power the fleet, together with a shift in the machinery used on-board, from steam turbines to reciprocating internal combustion engines (IMO, 2021).

In future years, CH₄ emissions from the transport sector are expected to increase up to 2035 and then stabilise at a slightly lower level. This projection relates to an important expected increase in international navigation compared to 2022, i.e. an increase of 1.3% in 2030 and 2.3% in 2050. At the same time, CH₄ emissions from road transport are expected to decrease by 9.0% by 2050 compared to 2022. Notably, projections also foresee an increase (up to 6.15 Gg) in emissions of CH₄ from domestic aviation in 2050.

Figure 11. EU-27 CH₄ emissions reported to the UNFCCC and to the EU Greenhouse Gas Monitoring Mechanism

1Absolute (Gg)2Shares — transport (%)3Shares — total (%)

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Figure 12 indicates that N₂O emissions from transport increased from 1990 to a peak in 1998, after which they fell and then rose again up to 2019, reaching 37.4 Gg, i.e. a 39.7% increase compared to 1990. In 2022 emissions where lower, reflecting the impacts of the COVID-19 pandemic; they equalled 36.1 Gg, a 35.0% increase compared to 1990.

Road transport is the main transport source for this GHG and air pollutant with a dominant contribution to ozone depletion. In 2022 road transport was responsible for 73.9% of all N₂O emissions from transport. Inspecting the historical trend it can be seen that passenger cars accounted for the first increase in emissions, while heavy-duty vehicles are responsible for the second one. In both cases, most of the N₂O emissions can be associated with unwanted catalytic reactions occurring in aftertreatment systems.

There are varying systems in use depending on the vehicle and engine technology (e.g. three-way catalysts (TWC), lean NOx traps (LNT), selective catalytic reduction units (SCR)) (Hoekman, 2020). In recent years, in diesel engines, NOx emissions have been mainly controlled through SCR systems which are known to produce N₂O under certain operating conditions (Selleri et al., 2021). This largely explains the latest increase in emission, apparent in recent years, especially for heavy-duty trucks, and still ongoing. According to data reported in the inventories, heavy-duty trucks emitted 10.6 Gg of N₂O in 2022, an increase of 131.1% compared to 1990. It has been shown that, in real world conditions, N₂O emissions from heavy-duty trucks can be very high and can represent a significant contribution to the overall CO₂e emissions of a vehicle (Selleri et al., 2022a, Giechaskiel et al., 2022a, Gioria et al., 2024). As mentioned above, the current methodologies used in GHG inventories may only partially capture this issue.

A switch to internal combustion engines using carbon neutral fuels or hydrogen, will not necessarily address this issue; they will continue to emit substantial quantities of NOx that will have to be regulated through aftertreatment systems, very likely SCR units. Thus, even if the direct combustion of such fuels does not release CO₂, significant quantities of climate-forcing gases could still be emitted in the process of controlling NOx.

Moreover, if SCR units to control NOx also become common in other sectors such as, for example, waterborne transport where diesel technology is ubiquitous, there is likely to be an increase in N₂O emissions, unless proper safeguards are included in the relevant air emission standards. Indeed, in diesel engines equipped with SCR units, unless NOx, NH₃ and N₂O emissions are regulated at the same time, the systems could be calibrated to minimise emission of some compounds at the expense of others. To note also that in the case of H₂ used as an energy carrier, H₂ itself can unintentionally slip into the atmosphere during combustion or in the production and transport processes. While H₂ is not a direct GHG, it affects atmospheric chemistry by impacting the lifetime of other GHGs, namely methane, ozone, and water vapour, with an overall climate warming effect (Arrigoni and Bravo, 2022).

In 2022, waterborne transport was responsible for 14.3% of all N₂O emissions across all transport sectors; this equated to 5.2 Gg (84.0% of which was due to international transport). Emissions in the sector increased by 15.3% in the 1990-2022 period.

Aviation, if we exclude the effects of the COVID-19 pandemic, contributed to 9.8% of overall N₂O emission from transport in 2019, with 3.5 Gg (89.2% coming from international transport). Emissions in the sector have increased by 81.4% in the 1990-2019 period.

In future years N₂O emissions are expected to decrease, mainly driven by a reduction in the contribution from road transport. Indeed, road transport N₂O emissions are projected to decrease by 20.9% and 48.5% in 2030 and 2050 respectively, compared to the levels for 2022. Notice that a further expansion in the contribution of aviation is expected, with an increase of 139.5% (10.9%) in its emissions by 2050 compared to 2022 (2019).

Figure 12. EU-27 N₂O emissions reported to the UNFCCC and to the EU Greenhouse Gas Monitoring Mechanism

1Absolute (Gg)2Shares — transport (%)3Shares — total (%)

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