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Aviation: journey to a sustainable future

Photo: pxfuel

Aviation is a key driver of global economic development, supporting mass employment and contributing 4.1% to the world’s GDP. It has seen multi-decadal growth in both passenger numbers and emissions. As the impact of climatic warming accelerates and the world’s climate action mission ramps up, the urgency with which aviation must reduce its contribution to atmospheric CO₂ will continue to gather pace – particularly given that other industries will find it much easier to decarbonise.

In 2009, aviation was one of the first industries to establish a global, sector-wide plan to reduce its impact on the environment. The commitment at the time was to reduce net CO₂ emissions to half of their 2005 value by 2050 – representing 325 million tonnes of CO₂ (MtCO₂). Nevertheless, global aviation emissions had increased to 915 MtCO₂ by 2019.

Taking their lead from the goal of the 2015 UN Paris Agreement – which set an international ambition to hold the increase in atmospheric warming to 2°C with an aspirational limit of 1.5°C – some nations and industry bodies have gone further and committed to achieving net zero CO₂ emissions by 2050. The UK became the first major economy in the world to pass laws to end its contribution to global warming – legislating to bring all greenhouse gas (GHG) emissions to net zero by 2050.

With the backdrop of these lofty ambitions, the International Air Transport Association (IATA – the industry’s largest trade association) forecasts that global air passenger journeys will see annual average growth of 3.7% over the next 20 years. This is despite the devastating impact Covid-19 has had on air transport. Other potential limits to growth, including the environmental concerns of consumers, governments moving to suppress growth or a shift to other modes of transport are all expected to have limited impact on the overall growth picture. With all this in mind, is net zero a realistic aim for aviation and how will the industry go about achieving it?

Michael Gill, Executive Director of the Air Transport Action Group (ATAG) certainly thinks so in his foreword to ATAGs Waypoint 2050 publication – an analysis of the climate change pathways for aviation to 2050:

“It took aerospace engineers around 30 years to get us from the first commercial air service to the jet engine. The last 30 years have seen us halve the CO2 emissions for every passenger’s journey. The next three decades to 2050, and the ones that follow, will allow us to enter the third era of aviation: that of sustainable fuels, electric and hybrid flight and, eventually, zero carbon connectivity”.

Aviation is perhaps one of hardest industries to decarbonise due to the lack of zero-carbon alternatives. The UK Committee on Climate Change (CCC) – who advise the UK government – agree that whilst a reduction of aviation emissions to net zero is theoretically possible, achieving it presents huge challenges both technological and political. The broad outline will mean first reducing emissions as much as possible, followed by using various GHG removal techniques to offset the remaining emissions. This action will need to be underpinned by a raft of international and domestic policy measures:

• Emissions Reductions

– Derived mainly from improvements in fuel efficiency through new technologies, aircraft design and operational efficiencies.

– Use of sustainable biofuels and potentially synthetic fuel, each giving a large life cycle carbon saving over fossil fuels.

– Managing demand through carbon pricing, taxation and the control of airport capacity.

• GHG Removal (offsetting)

Primarily via bioenergy with carbon capture and storage (BECCS) and the direct capture of CO₂ from the air (DACCS).

• Policy Measures

– Deep collaboration between government and industry.

– Significant and sustained funding for the latest research and development projects in sustainable aviation technologies – driving innovation for engine and aircraft design, biofuels and operational practices.

– Global policies must align with the intent of the Paris Agreement, providing a level playing field for airlines and reducing the likelihood of carbon leakage (where emissions simply move between airlines on the same or similar routes).

The great challenge in the coming decades will be to overcome these hurdles without stifling international connectivity and the many associated economic benefits this brings.

Time will tell if firstly, the political appetite and cooperation exists to drive aviation’s push towards net zero, and secondly whether the required technological advancements come to fruition. If not, then it is likely aviation will no longer be afforded its licence to operate – a scenario the current global economic model cannot endure.

Further reading:

ATAG Waypoint 2050 publication: https://www.atag.org/our-publications/latest-publications.html

Sustainable Aviation Decarbonisation Roadmap: https://www.sustainableaviation.co.uk/