The Role of Aviation in Global Warming
The aviation industry is a crucial part of our economy, with air transport experiencing significant historical growth and promising future projections. We rely on planes for everything from imports and exports to business travel and tourism, with approximately 40 million passenger flights a year. However, the importance of this industry comes with negative effects that continue to impact our climate.
Aviation significantly contributes to carbon emissions, accounting for approximately 2.5% of global CO₂ emissions. This disproportionate impact on global warming necessitates strategies to mitigate these emissions through improved fuel efficiency, the use of carbon-neutral fuels, and reduced air traffic.
Historical Trends in Aviation Emissions
The aviation industry has seen remarkable growth over the past few decades, which has significantly impacted global greenhouse gas emissions. According to the International Council on Clean Transportation (ICCT), carbon dioxide (CO2) emissions from commercial aviation have doubled from 0.5 billion tons in 1990 to 1 billion tons in 2019. This 100% increase in emissions over the past thirty years reflects an average annual growth rate of 3.5%.
This surge in emissions is primarily driven by the rising demand for air travel, especially in emerging markets like Asia and Latin America. Despite advancements in fuel efficiency, the overall increase in air travel has outstripped these gains, leading to higher emissions. The ICCT warns that if current trends continue unchecked, global aviation emissions could reach 1.5 billion tons by 2050, making it one of the fastest-growing sources of greenhouse gas emissions.
Understanding these historical trends is crucial for addressing the environmental impact of aviation and developing strategies to mitigate future emissions.
Aviation Emissions and Their Impact
Emissions from flying are a significant contributor to global greenhouse gas and CO2 emissions, playing a crucial role in climate change by significantly impacting global warming. Around 2.4% of global CO2 emissions come from aviation. When considering other gases released during flights and the water vapour trails produced by aircraft, the aviation industry can be held responsible for 5% of global warming.
The rapid growth in air traffic and the limited advancements in reducing commercial aviation emissions pose significant challenges, emphasizing the urgency for better regulations and alternative modes of transport.
CO2 Emissions from Planes
Planes release vast quantities of CO2. Calculating the CO2 emissions of flying involves considering various elements that affect how much CO2 is released per flight and person, and subsequently how detrimental each flight is to the environment.
Emission factors are crucial for accurately assessing carbon emissions related to air travel, as they take into account parameters such as flight distance and passenger occupancy rates, highlighting the complexity of understanding the true environmental impact of aviation.
The Importance of Altitude in CO2 Calculations
- You Thought Only Distance Mattered, Why Height is More Critical
The distance a plane travels obviously impacts how much CO2 is released per flight. However, a less-known factor that must be considered is altitude, which, like distance, has a direct warming impact on the planet.
This is due to "Radiative Forcing," which occurs when the amount of energy entering the Earth's atmosphere differs from the amount leaving it. If more radiation enters than exits, as is happening today due to the enhanced greenhouse gas effect, the atmosphere warms up. This process is known as radiative forcing because the energy differences can force changes in the Earth's climate.
When planes release contrails (water vapour that freezes around black carbon particles in the exhaust, appearing as white wisps in the sky), it exacerbates radiative forcing. These contrails trap heat, preventing it from leaving the atmosphere and warming the air below.
Marc Stettler, a lecturer at Imperial College London, found that changing planes' altitudes by just 2000 feet higher or lower could reduce contrail warming effects by up to 59%. Specific conditions are needed to form contrails, such as high humidity and low temperatures, meaning they do not form in all areas of the sky. Therefore, when calculating the warming effects and CO2 of flights, altitude must be considered, as flight paths through contrail-forming regions have more severe warming effects.
Plane Contrails and Radiative Forcing
Domestic Flight Emissions
Domestic flights, such as those within the UK, have a CO2e emission of 0.13 kg per KM per passenger. However, flights at altitudes where contrails are formed nearly double this to 0.2548 kg per KM per passenger.
International flights also contribute significantly to CO2 emissions, with specific aircraft types showing varying fuel consumption rates. Forecasts indicate a growth in passenger traffic for both domestic and international travel as the aviation industry recovers from the COVID-19 pandemic.
Example: London to Edinburgh Return
- With Radiative Forcing: 0.27 tonnes of CO2e
- Without Radiative Forcing: 0.14 tonnes of CO2e
Short-Haul Flight Emissions
Short-haul flights within Europe emit 0.08117 kg of CO2e per KM without radiative forcing, and 0.153 kg with it.
Example: London to Barcelona Return
- Without Radiative Forcing: 0.18 tonnes of CO2e
- With Radiative Forcing: 0.35 tonnes of CO2e
Long-Haul Flight Emissions
For flights outside of Europe, the CO2e emission is 0.1028 kg per KM without RF, and 0.19309 kg with RF.
Example: London to JFK
- With Radiative Forcing: 1.65 tonnes of CO2e
- Without Radiative Forcing: 0.87 tonnes of CO2e
Offsetting CO2 Emissions and Carbon Footprint
To offset a flight, one would need to plant 281 trees to remove the CO2 emissions in a year. For a long-haul flight, planting 3 trees would offset emissions over 25 years. Alternatively, a verified carbon credit for 1.65 tonnes costs around £20.
The Class of the Flight
Impact of Seating Class on Emissions
According to the ICCT, business class passengers are responsible for 2.6 to 4.3 times more emissions than economy passengers due to more space and amenities.
Economy Class
- More seats, less personal CO2 load
Premium and Business Class
Fewer seats, higher personal CO2 load
Flying premium or business class significantly increases your personal CO2 load due to the larger seats and additional services provided.
It is crucial for individuals to be conscious of their own carbon footprint, particularly through activities like flying. By examining personal habits and making lifestyle changes, such as reducing air travel, individuals can lessen their carbon emissions and contribute to broader discussions on climate change.
Additional services increase carbon footprint
First Class Emissions
- Short-haul with RF: 0.227 kg of CO2e per KM
- Long-haul with RF: 0.592 kg of CO2e per KM
Example: First Class London to New York Flight
- Requires offsetting 6.58 tonnes of CO2e
- Equivalent to planting 1,119 trees or purchasing verified carbon credits
Regulating Aviation Emissions
Regulating aviation emissions is a complex challenge that involves multiple stakeholders and international agreements. The International Civil Aviation Organization (ICAO) is the primary global body responsible for overseeing aviation emissions. In 2016, ICAO introduced a global market-based measure known as the Carbon Offset and Reduction Scheme for International Aviation (CORSIA).
CORSIA aims to cap net emissions from international aviation at 2020 levels, with an ambitious goal of reducing emissions by 50% by 2050 compared to 2005 levels. Under this scheme, airlines are required to purchase carbon offsets to compensate for their emissions. The revenue generated from these offsets is used to fund sustainable aviation fuels and other emissions-reducing projects.
In addition to CORSIA, various countries have implemented their own regulations to curb aviation emissions. For instance, the European Union’s Emissions Trading System (EU ETS) mandates that airlines operating in Europe purchase carbon allowances to cover their emissions. The funds raised through the EU ETS are also directed towards projects aimed at reducing emissions.
These regulatory efforts are essential for managing the environmental impact of aviation and promoting the development of sustainable aviation fuels and technologies. By understanding and supporting these regulations, we can contribute to a more sustainable future for global aviation.
Conclusion and Sustainable Aviation Fuels
Height, distance, and class significantly impact CO2 calculations for flights. Understanding these factors helps in offsetting travel emissions. However, beware of misleading low numbers; proper solutions involve accountability and investment. At SKOOT, we offer solutions, but it's crucial for individuals to take responsibility for their emissions.
