Long-Haul Flights: The Dark Side Of European Getaways

Air travel is a significant contributor to global warming, with aviation accounting for about 3.5% of effective radiative forcing to date. While flying, planes emit CO2 and other atmospheric gases and pollutants, such as soot, nitrous oxides, and water vapour, which have a warming effect on the atmosphere. The impact of aviation on the environment is significant, and with the number of flights projected to increase, it is essential to consider the pollution caused by a flight to Europe.

The environmental impact of aviation

Aviation has a significant environmental impact. Aircraft emit carbon dioxide (CO2), nitrogen oxides (NOx), soot, and other pollutants, contributing to global warming and air pollution. While flying, planes emit pollutants that have both warming and cooling effects on the atmosphere. The warming effect is stronger, and aviation is estimated to account for about 3.5% of effective radiative forcing, which measures the difference between incoming and outgoing energy, ultimately determining the temperature of the atmosphere.

The impact of aviation on the environment is not limited to climate change. Aircraft emissions also have negative consequences for human health and ecosystems. Nitrogen oxides, for example, are linked to lung damage, and exposure to fine particulate matter (PM2.5) can lead to respiratory diseases, lung cancer, and stroke. In 2021, 97% of people in European cities were exposed to PM2.5 concentrations above World Health Organization guidelines, and hundreds of thousands of people die prematurely in Europe each year due to air pollution.

The number of flights has increased, and with it, aircraft emissions. Between 2013 and 2018, emissions from planes rose by 32%, and they are projected to increase by nearly 50% in the next two decades. This is partly due to the growing number of passengers, which is expected to double in the next 20 years. While fuel efficiency improvements are being made, they are not keeping up with the increase in flights.

To reduce the environmental impact of aviation, several measures have been proposed. These include reducing corporate travel, as well as the use of clean fuels and e-fuels, such as e-kerosene, which can significantly lower carbon emissions. The European Union (EU) is also taking steps to address aviation's contribution to air pollution. From 2025, the EU will start monitoring non-CO2 emissions on all flights departing the bloc, and the European Aviation Safety Agency has published a report with proposed mitigation measures.

The health risks of air pollution

Air pollution is the presence of contaminants in the atmosphere, such as dust, fumes, gas, mist, odour, smoke or vapour, in quantities that can be harmful to human health. According to the World Health Organization (WHO), indoor and outdoor air pollution causes nearly seven million deaths worldwide each year.

The health effects of air pollution vary depending on the type of pollutant, the length and level of exposure, and other factors, including individual health risks and the cumulative impacts of multiple pollutants. The main pathway of exposure is through the respiratory tract, which can lead to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout the body, impacting the lungs, heart, and brain, among other organs. Fine particulate matter, such as soot, smog, and aerosols, can penetrate deep into the lungs, enter the bloodstream, and travel to organs, causing systemic damage to tissues and cells. Exposure to high levels of particulate matter can lead to reduced lung function, respiratory infections, and aggravated asthma in the short term, while long-term exposure increases the risk of stroke, heart disease, chronic obstructive pulmonary disease, and cancer.

Other common air pollutants with significant health risks include mercury, lead, dioxins, and benzene, which are often emitted during the combustion of fossil fuels, incineration, or found in gasoline. These pollutants can have severe health impacts, including eye, skin, and lung irritation, blood disorders, damage to the liver, immune, nervous, and endocrine systems, and adverse effects on reproductive functions.

In addition to the health risks associated with ambient air pollution, air travel also poses specific challenges. For example, the recirculated air in aircraft ventilation systems can increase the risk of exposure to allergens, such as peanut dust, and infectious diseases, such as SARS-coronavirus. Pregnant women may also face potential risks, including exposure to cosmic radiation, increased stress, and, in some cases, complications during delivery. Patients with cardiac problems represent a major group at risk for flight-related complications.

While the impact of aviation on climate change has been well-documented, the health risks associated with air pollution from flights are less frequently discussed. However, it is clear that the emissions and pollutants released by aircraft contribute to the overall degradation of air quality and pose significant health risks to the global population.

The economic impact of air pollution

Air pollution has a significant economic impact, causing a vast array of costs. Poor air quality has been linked to decreased workplace productivity, with 1.2 billion workdays lost globally each year, potentially rising to 3.8 billion by 2060. The World Bank estimates that the health damage caused by air pollution costs $8.1 trillion annually, equivalent to 6.1% of global GDP.

The burning of fossil fuels, which contributes to poor air quality, has significant costs. Air pollution exposure from fossil fuels costs each average American around $2,500 in additional medical bills. When coupled with higher temperatures, causing increased ozone pollution, the annual health costs in the United States rise to $7.9 billion due to worsened asthma and other health issues.

Air pollution also affects talent recruitment, as cities with severe air pollution are less desirable places to work. Some companies have offered hardship-posting compensation for employees relocating to cities with dangerous air pollution levels. Additionally, air pollution contributes to global crop yield losses of 3-16%.

However, research shows that the economic benefits of air pollution mitigation can outweigh the costs. For instance, the Clean Air Act in the United States has resulted in a 30:1 ratio between the economic benefits and the costs of pollution mitigation. Clean air action can boost economic growth, and since 2014, it has increased the EU economy by €50-60 billion annually. Improving air quality is crucial for building stronger economies and addressing climate change.

The ineffectiveness of current measures

The aviation industry is one of the fastest-growing sources of greenhouse gas emissions, and if left unaddressed, it will significantly contribute to the climate crisis. Despite the considerable impact of the sector, no concrete measures are in place at the regional or global level to reduce aviation's non-CO2 emissions. While the European Union has shown a preference for multilateral action, the lack of a common global system through the United Nations Framework Convention on Climate Change (UNFCCC) or the International Civil Aviation Organization (ICAO) has hindered progress.

The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) was introduced in 2016 to stabilize CO2 emissions at 2020 levels. However, this scheme only applies to volunteer states, and the impact of long-haul flights, which have a higher environmental impact, is not adequately addressed. Additionally, the scheme's effectiveness is questionable, as it relies on purchasing emission units from other sectors rather than directly reducing emissions in the aviation industry.

While the EU will start monitoring non-CO2 emissions on all flights departing from the bloc starting in 2025, this is a delayed response to the issue. The European Commission was first tasked with addressing non-CO2 emissions in 2008, and despite a landmark report published in 2020 analyzing the climate impact of aviation, the EU has been slow to implement meaningful changes. The proposed solutions, such as the use of clean fuels, exist but are not widely adopted.

Furthermore, the current measures primarily focus on CO2 emissions, neglecting the significant impact of non-CO2 emissions. Aviation affects the concentration of atmospheric gases and pollutants such as ozone, methane, water vapor, soot, sulfur aerosols, and water contrails, contributing to a net warming effect. This warming effect is estimated to be up to three times worse than the warming caused by aviation's CO2 emissions, yet it is not given the same attention or urgency in policy responses.

The protection of human health from air pollution has typically been addressed through regulations of air quality and emission standards. However, the geographic variability of health risks poses a challenge. Pollutants released into the environment fluctuate spatially, and the impact on populations can vary depending on their location. This variability is not adequately considered in current measures, leading to ineffective health protection for certain vulnerable regions. Additionally, ranking industries according to their effectiveness in health risk improvement can help facilitate better policy performance, but it is unclear if this is widely implemented.

Alternatives to air travel

A return flight from London to Berlin emits around 0.6 tonnes of CO2 per person, and a return flight from London to San Francisco emits around 5.5 tonnes of CO2 per person. Flying is the most damaging way to travel in terms of climate impact. However, there are several alternatives to air travel that produce fewer emissions.

One alternative is to travel by train. High-speed rail networks are being expanded in some countries, such as China, and there is a growing political movement in the US to build high-speed train lines as part of the Green New Deal. Travelling by intercity train releases just 41g of CO2 per passenger mile, which is significantly less than flying.

Another option is to travel by bus or coach. Buses are a common mode of transportation in almost every city worldwide, with many agencies offering regional, national, and international bus services. Travelling by coach releases even fewer emissions than trains, with just 28g of CO2 emitted per passenger mile.

Road tripping is another alternative to flying, which can be done by car or bike. Biking is a particularly popular way to travel in certain regions, such as the Leh Ladakh in India, which features some of the highest motorable roads and passes in the world. Group cycling trips are also organised in several countries, including the USA, Europe, and Latin America.

Finally, reducing corporate travel is an easy way to cut aviation emissions. During the COVID-19 pandemic, many employees adjusted well to working from home and flying less, indicating that flying for work is not as necessary as previously thought. By reducing corporate travel to 50% of pre-COVID levels, Europe could cut CO2 emissions by 32.6 MtCO2 by 2030, which is equivalent to taking 16 million polluting cars off the road.

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