The full-flight carbon dioxide (CO2) emissions of all flights departing from EU27+EFTA airports have followed a similar pattern to noise and continued to grow until an all-time high of 147 million tonnes in 2019. Figure 1.10a. shows the trends in full-flight CO2 emissions including future forecasts under different traffic, technology and air traffic management scenarios. Figure 1.10b. shows the net (i.e. lifecycle) CO2 emissions, including the effect of the EU Emissions Trading System (ETS) for the period 2013-2020 and that of in-sector measures including sustainable aviation fuels and new propulsion technologies (electric and hydrogen aircraft beyond 2035) under the base traffic scenario. No forecast of emissions reductions from market-based measures have been made due to on- going discussions on ETS and CORSIA at the European and ICAO level.

In 2019, aircraft operators covered 22% of their CO2 emissions by purchasing allowances under the EU ETS. The ETS has not fully mitigated the growth in CO2 emissions due to the growth in emissions from flights outside its applicability scope. CO2 emissions dropped by 57% in 2020 due to the start of the COVID-19 pandemic. If the ReFuelEU mandate16 for sustainable aviation fuels is met, net CO2 emissions could be about 50% lower in 2050 than in 2019. Electric and hydrogen aircraft were assumed to deliver an additional 5% net CO2 reduction by 2050 and are expected to have a larger emission reduction potential beyond this date.

Emissions of nitrogen oxides (NOx) shown in Figure 1.12. , as well as volatile particulate matter (PM), have followed an even steeper growth since 2005, respectively +46% and +40%. Emissions of carbon monoxide (CO), unburnt hydrocarbons (HC) and non- volatile PM have also grown but at a lower rate (+4% to +13%). Under the base traffic scenario, the most optimistic technology and air traffic management scenario would bring NOx emissions close to their 2019 levels in 2050. The same applies to CO and volatile PM emissions, while HC and non-volatile PM emissions could reduce between 2019 and 2050 ( Figure 1.15. ).

In 2019, long-distance flights (above 4,000 km) and twin aisle jet aircraft represented approximately 6% of departures and half of all CO2 and NOx emissions ( Figure 1.13. ), while intra-EU+EFTA flights represented 77% of flights and 39% of CO2 emissions ( Figure 1.14. ).

European aviation emissions in context

Flights departing from EU27+EFTA represented 16% of global aviation’s CO2 emissions in 2018. In 2019, all departing flights from Europe were accountable for 5.2% of the total EU27+EFTA greenhouse gas emissions (an increase from 1.8% in 1990) and 18.3% of emissions from the transport sector, making aviation the second largest source of emissions in the transport sector after road [3] . This increase is due to traffic growth outpacing fuel efficiency improvements and reductions of emissions from other sectors. In 2020, aviation emissions decreased to 1.9% of total EU27+EFTA greenhouse gas emissions and 9% of emissions from the transport sector.

Aviation is also an important source of air pollutants, especially nitrogen oxides (NOx) and particulate matter (PM). Compared to 2019, the 2020 share of aviation NOx emissions within the transport sector has dropped from 22.8% to 13.4% within EU27+EFTA, while the share in total NOx emissions almost halved from 10.6% to 6% [4] . In absolute terms, NOx emissions from aviation have almost tripled since 1990, and their relative share has quadrupled, as other economic sectors have achieved significant reductions. For emissions of PM2.5, the total share from aviation is less than 1% while it accounted for 5% from the transport sector. Emissions of PM2.5 have slightly increased since 2000. The carbon monoxide (CO) and oxides of sulphur (SOx) emissions from aviation have also increased since 1990, while these emissions from most other transport modes have fallen.


Towards decarbonisation of aviation

According to the UNEP Emissions Gap Report 2020 [5] , domestic and international shipping and aviation currently account for around 5% of global CO2 emissions and are projected to consume between 60% and 220% of allowable CO2 emissions by 2050 under IPCC illustrative 1.5°C scenarios.

In 2021, the Science Based Targets initiative (SBTi) published guidance for passenger and cargo airlines to set their own CO2 reduction targets [7] . This guidance helps companies understand how much and how fast they should reduce their greenhouse gas (GHG) emissions to align with the goals of the Paris Agreement. The target setting method for airlines is based on the SBTi’s Sectoral Decarbonization Approach (SDA), which states that a company’s GHG intensity (grams CO2 equivalent per revenue tonne kilometre) should converge to the sector’s average Paris-aligned GHG intensity by 2050.

In March 2022, ICAO published a report on the feasibility of a long-term aspirational goal (LTAG) for international civil aviation CO2 emission reductions [8] . The study looked at various integrated scenarios combining in-sector measures (technology, operations and fuels) out to 2050 and 2070. While none of the scenarios in the study reached zero CO2 emissions in 2050, the most ambitious one (IS3) led to residual CO2 emissions of ~200 million tonnes (i.e. ~90% less than the baseline “do nothing” scenario or one third of emissions in 2019). Further discussions on the feasibility of an LTAG are due to take place at ICAO’s 41st Assembly in October 2022.

International Aviation CO2 Emissions


16 As per the European Commission ReFuelEU Aviation Initiative proposal of July 2021.