Clearing the Air: How Airlines are Cutting Greenhouse Gas Emissions

According to the European Union, direct emissions from aviation account for about 3% of the EU’s total greenhouse gas emissions. On a global scale, the figure is circa 2.5% of CO2 emissions.

Despite aviation being one of the most carbon-intensive activities, these figures are relatively modest. The reason is simple: not everyone flies. According to Gössling & Humpe (2020), just 10% of the world’s population flies over the course of most years. But things are changing.

The global figures have been relatively stable for many years, but have increased since around 2010, reflecting, what we believe to be, the general increase in rising incomes in certain areas of the world, as well as the increase in online-purchase generated activities, resulting in a rise in small-item transportation movements.

It is certainly the case that the International Air Transport Association (IATA) released data recently for February 2024 global air cargo markets showing continuing strong annual growth in demand. Total demand, measured in cargo tonne-kilometres (CTKs) rose by 11.9% compared to February 2023 levels.

The number of flights performed globally by the airline industry has increased steadily since the early 2000s, reaching 38.9 million in 2019. Due to the global pandemic, that figure dropped to 16.9 million in 2020, but has increased in the years following that. In 2024 it reached a new peak of 40.1 million flights.

Although relatively minor by comparison, we must also add the impact of military aviation emissions, likely to increase as many countries increase their military capabilities in the face of global instability.

The picture looks grim, but there is light on the horizon.

Airlines fall in scope for TCFD (Taskforce on Climate-related Financial Disclosures) which, amongst other reporting standards and mandated reporting requirements, has raised awareness across the airline and air transport industry of both their contribution to GHG emissions and climate change, and the ways in which the contribution might be mitigated.

The European Union has led the way from a regulatory perspective with its aviation Directive, under the banner of ‘Fit for 55’. On 14^th July 2021, the European Commission adopted a series of legislative proposals setting out how it intends to achieve climate neutrality in the EU by 2050. This includes an intermediate target of an at least 55% net reduction in greenhouse gas emissions by 2030 – the so-called ‘Fit for 55’.

Previous fuel-efficiency initiatives have already led to a drop in the amount of aviation fuel burned per passenger by 24% between 2005 and 2017. However, the environmental benefits have been outpaced by the sustained growth in air traffic. In 2017, passengers flew on average 60% further than in 2005.

According to the EU, if global aviation were a country, it would rank in the top 10 emitters.

Placing the emissions in context, a person flying from Lisbon to New York and back generates roughly the same level as the average person in the EU does by heating their home for a year.

CO2 emissions from aviation were included in the EU emissions trading system (EUETS) which requires all airlines operating in Europe (European and non-European) to monitor, report and verify their emissions, and to surrender allowances against those emissions.

This system has so far contributed to reducing the carbon footprint of the aviation sector by more than 17 million tonnes per year, with compliance covering over 99.5% of emissions.

From 2021, the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), set out to stabilize CO2 emissions at 2020 levels by requiring airlines to offset the growth of their emissions after 2020.

But, of course, airlines are only part of the story.

Improved air traffic management systems, the development of new and improved engine technologies, the widespread use of lighter materials in aircraft construction, together with pioneering work in the area of sustainable aviation fuels, are looking increasingly like bright lights on the aviation sustainability horizon.

According to Airbus Industries, sustainable aviation fuels can reduce CO2 emissions, on average, by 80% compared to traditional jet fuel. Other low-impact technologies such as electric and hydrogen-powered aircraft are also being developed by major aviation companies. In fact, the first electric aircraft to fly under its own power with a person on board flew for 9 minutes from Linz in Austria on 21^st October 1973. We’ve come a long way since then.

The industry’s efforts are not only on a grand scale. I’m sure that anyone traveling by air will have noticed the increasing pressure on the amount of luggage that can be carried, with financial penalties often used to keep levels to a minimum. Reductions in weight, mean reduced emissions. It’s that simple.

When it sets its mind to goal-achievement, the aviation industry is a formidable force. Who, for example, could have predicted on 17^th December 1903, when the first flight of the Wright Flyer took place, that a mere 120 years later, aviation would have become the enormous industry it is today.

Like many of the world’s climate and environmental challenges, there is unlikely to be a single solution to the aviation industry’s GHG emissions challenge. However, it was the spirit of collaboration that led to unprecedented levels of safety, the universal introduction of ‘black boxes’ in aircraft and the sharing of technological advances, that will drive the industry’s climate-impact agenda forward.

The solution to reducing the aviation industry’s GHG emissions, and its impact on the climate and the environment, will be the agglomeration of fuel technologies, new construction materials, better flight sequencing, improved engine technologies, use of AI and other digital technologies, changes to passenger habits but, above all else, the significant change in attitude of everyone involved.