How Rising Aviation Emissions Threaten UK’s Climate Targets

Article by Ashwin Aggarwal, student of history and politics at the University of Warwick.

From 2023 to 2024, aviation emissions rose by 9% on the previous year, an indication that achieving Net Zero by 2050 appears increasingly less likely. Major news included approval for runway expansions at Gatwick and Luton in April and September last year. And in November 2025, the Transport Secretary confirmed the preferred scheme for expansion at Heathrow. If approved, this expansion would result in an estimated 4.4 million tonnes of carbon dioxide equivalent (MtCO₂e) per year from this single runway alone.

Meanwhile the Climate Change Committee (CCC) – the independent climate change advisory body to the UK government – has explicitly warned that aviation emissions must stay close to today’s levels until the mid-2030s. This advice has been largely ignored. The aviation industry presents few signs of slowing down and I argue unless policy shifts decisively from an efficiency-based approach to one of sufficiency, we should not expect to meet our legally binding climate goals. With this come serious environmental and political repercussions. Let me explain why.

The Argument for Efficiency

The efficiency-based approach argues that aviation emissions can be reduced without limiting demand, primarily through technological improvements and alternative fuels. This proposal rests on the development of Sustainable Aviation Fuel (SAF): fuels made from feedstocks including biofuels, oils, waste and renewables. SAFs are often presented as low-disruption solutions, as no engine modifications to aircraft are required.

There is evidence that development in efficiency has delivered some progress. According to the Carbon Budget and Growth Delivery Plan (CDGBP), the UK must ensure that 10% of jet fuel used is made from SAFs by 2030. Current emissions reductions data indicate good progress: from 2023-2024, the UK increased its SAF proportion by 0.7% to 2.1%. Following these increases, it may appear reasonable to expect proportions to reach mandated targets of 22% by 2040. This leaves the impression that aviation can be decarbonised without reducing passenger demand.

However, I argue there are several issues with this line of thought. The first is whether a 22% SAF proportion is sufficient to satisfy Net Zero targets by 2050. Net Zero requires a total shift to low-carbon sources where no emissions are produced. That being said, Net Zero is an uneven process. In the transport industry for example, rates of new electric vehicle (EV) sales stood at 19.6% in 2024. Predictions that this rate will increase to 94% by 2030 may seem absurd at first glance, yet achievability is often nonlinear. As the price of EVs reaches parity with Internal Combustion Engines (ICEs) adoption accelerates as it becomes more affordable to shift to renewable forms of driving. SAF enthusiasts are thus resting their hopes on scaling up SAF sales in aircrafts when the market permits.

The Case for Sufficiency

However, there is a fundamental issue with this model and its demanded extraction of nature’s resources. Fuels made from hydrogenated esters and fatty acids (HEFA) are constituted from residues of cooking oils: chips, tallow, samosas. Yet these resources are finite and cannot be expected to support the aviation sector. Whilst the nation may relish fish and chips, our eating habits do not generate sufficient quantities of fuel for large-scale SAF production. That leaves us with expecting a change in national diets to supply aviation fuels, a proposal both not credible and unlikely given the growing climate of obesity in the UK.

Power-to-Liquid (PtL) is often presented as a long-term alternative to HEFA fuels, but they too face barriers in production. Whilst science lists two distinct forms of PtL production, both require huge energy demands. The first method is synthesising CO₂, water and renewable electricity to produce hydrogen. Meanwhile the second uses electrolysis of water to produce hydrogen, which is added to with sustainably sourced CO₂. There are two key issues. First this process is subject to uncertainty: Airbus recently announced delays to its hydrogen aircraft concept originally planned for market delivery by 2035. We should not expect PtL involvement in SAFs to increase significantly in the near future. Second, the requirement for renewable electricity in both production processes raises serious concerns regarding the sufficiency of resources across all industries.

The UK, like all countries in the world, does not have an unlimited supply of renewables. That only 28% of British Industry is ‘electrified’ suggests serious shortfall in the pathway to Net Zero. Current and future plans are impressive – including an additional 15GW offshore wind by 2029 – but these do not even meet current domestic demand, let alone international aviation needs. Whilst renewable capacity is increasing, there remains a serious risk that renewable energy will be diverted from key sectors, including transport and heating, to meet aviation demands.

Conclusion

Thus I suggest our fascination with portraying negative emissions technology (NET) as the ‘hero’ that will save us from the climate crisis is problematic. Simply put, efficiency alone may not be the answer. Our planet’s resources are finite. Where land and energy are required for Carbon Capture Storage (CCS), forest protection, renewable deployment, agriculture and housing, balancing nature’s resources is just as important as investing in new technologies. The larger the proportion of sustainable fuels, the greater the environmental pressure placed on ecosystems. Therefore, I stress that future aviation mitigation policy must take a fundamentally different approach – one rooted in sufficiency, not efficiency to guarantee a better future for this planet.