Background

The report investigates the aviation sector’s ability to meet net-zero CO2 emissions by 2050. Given the projected growth in air traffic and fleet size, achieving this goal requires significant advancements in sustainable aviation fuels (SAFs) and zero-emission planes (ZEPs). The study defines a net-zero carbon budget of 18.4 billion tonnes for the sector, calculated from four industry decarbonisation roadmaps.

Methodology

The analysis projects lifetime CO2 emissions from the 2023 global fleet and new aircraft deliveries through 2042 under three scenarios: Baseline, Optimistic SAF, and Optimistic SAF + Fuel Efficiency. The scenarios vary in their assumptions regarding the uptake of SAFs and improvements in fuel efficiency. Committed emissions from the existing fleet were calculated using data on average mission speed, fuel burn, and fleet composition. New aircraft deliveries were modelled based on forecasts from Boeing, Airbus, and Embraer.

Results

The 2023 in-service fleet is expected to emit approximately 9 billion tonnes of CO2 before retirement, consuming almost half of the net-zero carbon budget. Under the Baseline scenario, lifetime emissions from new aircraft delivered between 2024 and 2042 are projected to exhaust the balance of the net-zero carbon budget by 2032. The Optimistic SAF and Optimistic SAF + Fuel Efficiency scenarios extend this timeline to 2037, demonstrating the impact of increased SAF uptake and fuel efficiency improvements. Nonetheless, to achieve net-zero emissions, all new aircraft delivered by the mid-2030s will need to be zero-emission.

Recommendations

The report offers three key recommendations for aircraft manufacturers:

• Accelerate the development of narrowbody ZEPs, especially those powered by hydrogen, to achieve zero CO2 emissions during operation.
• Ensure compatibility with 100% SAFs for all new aircraft starting in 2030, not just SAF blends.
• Establish stringent Scope 3 emission targets, aiming for net-zero emissions from aircraft over their lifetimes by 2035.

Comparison with carbon budgets

In the Baseline scenario, aviation emissions are projected to deplete the net-zero carbon budget by 2032 due to fleet growth and limited technological improvements. The Optimistic SAF + Fuel Efficiency scenario reduces lifetime emissions from new deliveries by more than 50%, delaying budget exhaustion to 2037. Despite these measures, the study emphasises the need for manufacturers to transition away from fossil fuels by the mid-2030s to align with climate goals.

Potential future research

The study suggests further research on the impacts of fleet evolution on non-CO2 forcings and regional differences in fleet growth. It also highlights the importance of standardising methodologies for calculating Scope 3 emissions to improve comparability across manufacturers.