Airport capacity constraints and demand reduction on flying needed to hit net zero target, says report

A report by low carbon energy consultants Element Energy (EE) analysing the UK government’s ‘Jet Zero’ strategy to hit net zero aviation emissions by 2050, with interim reduction targets for the 2030s, concludes the scenarios are over-optimistic. The report, commissioned by UK campaign group the Aviation Environment Federation, concludes acting early by halting airport capacity growth along with implementing other demand reduction measures pose a far less risky approach to reaching the targets. EE estimates the aviation sector will need to cut emissions faster and deeper in the near term than the government is currently projecting. The government’s plans overestimate the likely improvements in operations, technology and alternative fuels, along with out-of-sector solutions such as engineered GHG removals, and are unlikely to be developed at the speed and scale necessary, it argues. AEF, meanwhile, has joined with other NGOs in calling on the government to withdraw its policy support for UK airport expansion until aviation emissions start falling and wider emissions are “substantially below” a 1.5°C-compliant trajectory.

Despite aviation demand – in terms of UK terminal passengers – being forecast to increase by over 70% in the latest government assumptions between 2018 and 2050 under its High Ambition scenario, aviation is expected to be one of only two sectors (the other being agriculture) still to have residual emissions in 2050, with very high-cost carbon removals required to mitigate this. As laid out in its Jet Zero further technical consultation in March 2022, possible trajectories by the UK Department for Transport (DfT) show in-sector CO2e emissions of 36Mt in 2030, 28Mt in 2040 and 15Mt in 2050, or net CO2e emissions of 24-29Mt in 2030, 12-17Mt in 2040 and 0Mt in 2050. The latest government statistics show international aviation emissions in pre-pandemic 2019 amounted to 37MtCO2e, which have more than doubled since 1990, with a further 1.5MtCO2e from domestic flights.

As part of its net zero by 2050 commitment, the UK aviation industry last year announced interim decarbonisation targets of a net reduction in emissions by “at least” 15% by 2030, relative to 2019, and a 40% net reduction by 2040 as, said its Sustainable Aviation cross-sector alliance, “with the pace of decarbonisation ramping up as game-changing sustainable aviation fuels, permanent carbon removal, and new low and zero-carbon technologies – such as electric and hydrogen-powered aircraft – become mainstream in the 2030s.”

However, the report by Element Energy says the High Ambition scenario “is over-reliant on emerging high-risk technologies and uncertain policy in the forecasting of the emission abatements in 2035.” Key risk factors, it says, include a slow-down in aerospace R&D spend post-Covid that makes it unlikely efficiency improvements will achieve a step-change growth of 2.0% annually from 1.5% historic levels. It is also pessimistic about the higher levels of SAF demand required by 2035 to meet the High Ambition scenario and questions as misleading the 100% emissions savings assumed from SAF. In addition, it criticises the exclusion of aviation non-CO2 effects as substantially underestimating aviation’s warming impact.

It also says the scenario sees a substantial emissions abatement in 2050 relying on CORSIA carbon pricing on long-haul flights reaching ETS levels, which it believes is unlikely. CORSIA, ICAO’s global carbon offsetting scheme for international aviation, is currently designed to end in 2035.

“Overall, it is unclear how DfT plans to deliver these high rates of technological improvements, SAF uptake and aircraft efficiencies,” says the report. “Expanding carbon pricing, with EE estimations suggesting that only about 17% of total aviation emissions are currently priced, would also be essential to support the rapid uptake of new technologies by airlines but would rely on breakthroughs at ICAO in terms of the level of ambition in CORSIA and future arrangements for a market-based measure after 2035.”

EE says relying on greenhouse gas removals is also risky and argues “they should only be deployed once both technological and behaviour change options to reduce emissions have been exhausted.”

It suggests demand management policies could take several forms, including reducing passenger demand for flying through carbon pricing, an air miles or frequent flyer levy, applying VAT or reforms to Air Passenger Duty, and restricting the availability of flights through management of airport capacity. Additional non-financial behaviour change interventions could include improved marketing of domestic tourism opportunities and consumer information about the CO2 impacts of flights.

“Constraining demand now through airport capacity is far easier and more reliable than allowing capacity and demand to grow and then rapidly trying to reduce demand in the future through pricing mechanisms,” says EE. “We conclude that there should be no airport expansion until and unless it is clear that both in-sector (aircraft technology) and out-of-sector (carbon removal) emissions reductions are on track to meet a fair emissions reduction for 2035 and beyond.”

Commenting on the findings, Cait Hewitt, Policy Director at the Aviation Environment Federation, said: “The government’s plan is to sit back and allow both airports and emissions to grow in the short term while hoping for future technologies and fuels to save the day. This new report gives a damning appraisal of the level of risk in every aspect of the current approach to aviation emissions and highlights the need for action now, including ruling out airport expansion and limiting demand, to ensure aviation makes a fair contribution to cutting emissions by 2035 and is on a pathway to net zero by 2050.”

On the back of the report, AEF and six other environmental NGOS – AirportWatch, Friends of the Earth, Green Alliance, Greenpeace, Possible and Transport & Environment – have written an open letter to Aviation Minister Robert Court that calls on the government to withdraw its support for airport expansion in the UK. The letter also expresses concern over the assumptions the government’s Jet Zero draft strategy makes on increases in sustainable fuels and carbon removals occurring after 2030, “but with no clear policy plan to ensure they are delivered.”

Photo: Heathrow Airport