Aircraft Emissions

Aviation is responsible for 2.5% of global CO₂ emissions [1]

Data source: Calculated by Our World in Data based on Lee et al. (2020); Bergero et al. (2023); and Global Carbon Project. Note: Factors other than CO₂ from aviation and increased warming due to altitude are not included.OurWorldInData.org/energia | CC BY [1]

But it has contributed about 4% of global warming to date [1]

Although aviation accounts for approximately 2.5% of global CO2 emissions, it's contribution to climate change is more significant. In addition to CO2 emissions, aircraft influence the concentration of other atmospheric gases and pollutants. For example:

Nitrogen oxide (NOx): Temporarily increases ozone (a greenhouse gas) and long-term reduces methane (another greenhouse gas).
Water vapour: Emitted by aircraft exhaust, contributes to the formation of clouds and contrails.
Soot and sulfur aerosols: Can both warm and cool the atmosphere depending on conditions.

David Lee et al. (2020) quantified the overall effect of aviation on global warming using “radiative forcing”, which measures the difference between incoming solar energy and energy radiated into space. When the absorbed energy exceeds the radiated energy, the atmosphere warms. Studies indicate that aviation has contributed approximately 3.5% of global radiative forcing to date and is responsible for 4% of the global temperature increase since pre-industrial times.

About two-thirds of the warming caused by aviation comes from non-CO2 forcings, such as:

Contrails: Formed by water vapor from aircraft exhaust, they have a significant warming effect.
Nitrogen oxides (NOx): Temporarily increase ozone and long-term reduce methane.

This explains why, although aviation contributes only 2.5% of global CO2 emissions, its total warming impact is greater.

Carbon emissions from commercial flights are set to triple by 2050, amid growing demand for travel and freight [2]

However, it is possible to reduce these emissions by 85% through demand management, technological improvements in efficiency and the widespread use of biofuels. The International Council on Clean Transportation (ICCT) offers guidance on how to design pragmatic policies using research on aviation technologies, fuel efficiency and alternative fuels.

Figure 1. Average fare increase for 30 routes by country of carrier registration and assignment method, along with the average carbon intensity of routes by country of carrier registration.

aviazione icao 2023.pdf

Regulate emissions from international aviation without distorting the market

Objectives and Regulations

The International Civil Aviation Organization (ICAO) has established a Long-Term Aspirational Goal (LTAG) to achieve net-zero CO2 emissions in international aviation by 2050. To facilitate this goal, member countries are encouraged to develop State Action Plans (SAPs) that serve as roadmaps.

Policy Impact Analysis

A recent analysis evaluated the market effects of two different methods of regulating CO2 emissions in commercial aviation on 30 international routes in China, Europe and the United States. The study applied regional carbon taxes to airfares based on the operator's country of registration and country of departure. The results showed that regulation based on the country of registration can introduce market distortions, leading to higher airfares for carriers located in countries with higher carbon prices.

Emissions Reduction Strategies

Demand management: Introduction of policies that encourage the use of less polluting alternative transport, such as the train, especially for medium-short distances.
Technological efficiency: Investment in advanced aviation technologies that improve fuel efficiency and reduce aircraft energy consumption.
Alternative fuels: Promotion and use of sustainable biofuels that can replace traditional fossil fuels, significantly reducing the carbon footprint of the aviation sector.

To address the expected increase in carbon emissions in commercial aviation, it is essential to implement a combination of strategies that include demand management policies, technological improvements and the adoption of alternative fuels. Only through an integrated and well-regulated approach will it be possible to reach the goal of net zero emissions by 2050 without causing significant market distortions.

Figure 2. Consumption of the aviation carbon budget from cumulative emissions over the expected fleet life

ID-188-–-Committed-emissions_wp_final.pdf

Lifetime aircraft emissions with a net zero carbon budget

Commitment to Zero Emissions

In 2022, airlines and aircraft manufacturers promised to achieve net-zero CO2 emissions by 2050. However, the commercial aviation sector is expected to grow rapidly, with traffic potentially doubling, thus also increasing the fleet and the use of aircraft.

Evaluation of Decarbonization Projections and Scenarios

This paper examines whether current aircraft delivery projections are aligned with the goal of net zero emissions by 2050. Using models that consider 2023 global fleet CO2 emissions and new aircraft deliveries up to 2042, we have three decarbonisation scenarios analysed:

Baselines
Sustainable Aviation Fuels (SAF)
Optimistic SAF + Fuel Efficiency

Search results

2023 fleet: Expected to emit around 9 billion tonnes of CO2 before being retired, nearly half of the net zero carbon budget.
New Aircraft (2024-2042): Overall emissions will exhaust the net zero carbon budget between 2032 (baseline scenario) and 2037 (optimistic SAF + fuel efficiency scenario).

Implications for the Aviation Sector

To meet climate targets, all new aircraft delivered by the mid-2030's will have to emit zero net CO2 emissions throughout their operational lives. A market is expected for at least 10,000 new aircraft powered by hydrogen, electricity or 100% SAF by 2042.

Recommendations for Aircraft Manufacturers

Development of Zero Emissions Aircraft (ZEP): Accelerate the development of ZEPs, especially hydrogen-powered narrow-body aircraft.
100% SAF usage: Ensure all new aircraft can use 100% SAF, starting in 2030.
Value Chain Emissions Targets: Set aggressive targets to reduce emissions throughout the entire product lifecycle.

To reach the goal of net zero CO2 emissions by 2050, the aviation sector will need to significantly increase investments in low-emission technologies and zero-emission aircraft.

This graph shows the different activities that contribute to tourism’s total carbon footprint. Data Source: Nature Climate Change (2018) [3]

The impact of global tourism

Access to increasingly low-cost air travel through low-cost airlines has had a huge effect on tourist numbers globally. Tourists, in addition to travelling, use energy for accommodation, services and purchases. Tourism's carbon footprint is equivalent to 8% of global human emissions. About half of these emissions are due to transportation. For domestic tourism, residents mainly use the car, followed by the plane. International travel, whether continental or intercontinental, is mostly carried out by air [3].

"In 1950, passengers entering the United States were 23 million. In 2018, they were 1.4 billion, 56 times more. In Italy, the increase was around 275%: the number of passengers arriving arrival went from 276 thousand in 1950 to 75 million in 2014, equal to 1.3 times the Italian population [4]."

In 2030 it is estimated that greenhouse gases will grow by 25% with 2 Gt of CO2, linked to transport attributable to tourism [4].

Figure Dx United Nations World Tourism Organization (UNWTO, 2023) – OurWorldInData.org/tourism | CC BY [5]

Figure Sx: These are averages based on 2020 UK conversion factors. Values will vary based on distance traveled, vehicle model, occupancy rate, flight class, and various other factors. [3]

Solutions - Reducing Demand for Air Travel: "A Goal for Businesses" [6]

The Flight Problem as the Default Option

Impact of Frequent Flyers: Those who fly more than three times a year belong to a minority that has a disproportionate environmental impact.
Carbon Footprint: Carbon calculators show how emissions from air travel can quickly dominate our personal carbon footprint.

Technological Solutions and Demand Reduction

Tecnologie Future: Biocarburanti e energia a idrogeno sono in sviluppo ma non ancora pronti per l'uso commerciale.
Azione Immediata: È necessario ridurre ora la domanda di viaggi aerei per mitigare le emissioni.

The Role of Companies

In the service sector such as universities and consultancy firms, many frequent travelers are hosted. 30% of business travelers fly for work at least once a month. An example of data analysis was carried out at Imperial College, where aviation accounted for 9% of total emissions in the 2017/18 academic year. 15% of travelers were responsible for 50% of recorded emissions.

Ripensare i Viaggi di Lavoro

The first question to ask is whether the trip is really necessary. Video conferencing and the use of local scientists/staff/entrepreneurs can replace many business trips, this type of reduction does not have a correlation to a negative impact on professional success. Let's take an example of an Alternative Work Trip by analyzing the "Amsterdam-London" route.

Fly or Take the Train?: In 2016, 1.6 million people flew from Amsterdam to London. However, the high-speed train via Brussels is a valid alternative.
Time and Emissions: Considering the time for check-in and transfer, the flight takes 4 hours and 50 minutes, while the train takes 4 hours and 30 minutes. The flight produces 57 kg of CO2 per person, compared to 3 kg by train.
Emissions Comparison: The amount of CO2 produced by a flight is equivalent to that generated in a month by an average UK household through electricity consumption.

To reduce the environmental impact of air travel, companies must adopt policies that favor more sustainable means of transport, rethinking the need for travel and preferring alternatives such as trains ("slow travel") that offer significant environmental benefits. Changing the default travel options for continental travel. Here are some examples of advantages:

Productivity: Time spent on the train can be used productively for work, without the interruptions and space limitations of flying.
Luggage and Liquids: Train travel has no restrictions on liquids or luggage, making travel less stressful.
Networking: Traveling by train to large conferences in Europe can turn into a networking opportunity, as many scientists and professionals choose the train, facilitating meetings and discussions during the journey.
Efficiency of Sleeper Trains: Europe is crossed by a network of sleeper trains that connect various cities, such as Prague and Venice, making night travel an efficient solution. This allows travelers to save on accommodation costs at their destination.
Reduction of Carbon Emissions: The difference in carbon emissions between trains and planes is significant. For example, taking the train from London to Prague saves 153kg of CO2, the equivalent of the emissions generated to power a house for three months.

By implementing these policies, companies not only contribute to environmental sustainability, but also improve the travel experience of their employees, offering them more comfortable and less stressful options.

ICAO Carbon Emissions Calculator (ICEC)

The ICAO Carbon Emissions Calculator (ICEC) is a tool developed by the International Civil Aviation Organization to calculate carbon dioxide (CO2) emissions from air travel. This calculator was created to support carbon offset programs and is based on a methodology that uses the best data available in the industry.

Main Features of the ICEC:

Advanced Industry Data:
- Types of Aircraft: Consider the different types of aircraft used in commercial flights.
- Route Specific Data: Use detailed airline route information to accurately calculate emissions.
- Load Factors: Takes into account passenger and freight load factors, which affects fuel consumption and emissions.
Ease of Use:
- Simple Interface: Requires only a limited amount of information from the user, such as departure and arrival airport.
- Accessibility: Publicly available and simple to use for anyone who wants to estimate their carbon emissions.
International Standard:
- Global Recognition: It is the only internationally approved tool for estimating carbon emissions from air travel, lending credibility and standardization to the calculations performed.

How does ICEC work?

The user enters the departure and destination airport, as a result the calculator uses industry data, such as aircraft type, specific route and load factors, to calculate CO2 emissions. The resulting result is the estimated carbon emissions for the specified trip, which can be used for offsetting purposes or for environmental awareness. More and more travelers are using this tool to understand the environmental impact of their air travel, promoting more sustainable choices.

Are you curious?

I'll leave you the link/button below so you can try it right away! and have fun calculating your trips!

ICAO Carbon Emissions Calculator (ICEC)

Bibliography

[1] Hannah Ritchie (2024) - “What share of global CO₂ emissions come from aviation?” Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/global-aviation-emissions' [Online Resource]

[2] Gates, B. (2021). Clima. Come evitare un disastro. La Nave di Teseo Editore spa, pp, 204. https://theicct.org/sector/aviation/

Godin, S. (Ed.). (2022). The Carbon Almanac: It's Not Too Late. Penguin:

[3] “Carbon Footprint of Tourism”. Sustainable Travel International, 2020, https://sustainabletravel.org/issues/carbon-footprint-tourism/.

[4] Godin, S. (Ed.). (2022). The Carbon Almanac: It's Not Too Late. Penguin, pp, 150.

[5] “Tourism”. Our World in Data, Apr. 2017. ourworldindata.org, https://ourworldindata.org/tourism.

[6] “Reducing Demand for Air Travel Starts at Work”. Grantham Institute at Imperial College London, 3 Feb. 2020, https://granthaminstitute.com/2020/02/03/reducing-demand-for-air-travel-starts-at-work/

Page updated

Google Sites

Report abuse