Direct carbon dioxide emissions from commercial passenger aircraft are expected to increase by 87% between 2025 and 2050, according to new forecasts from aviation consultancy IBA.
Analysis from IBA's NetZero sustainability platform suggests annual tailpipe emissions will rise from around 843 million tonnes of CO₂ in 2025 to 1.58 billion tonnes by 2050. The figures represent gross tank-to-wake emissions and do not account for the potential impact of sustainable aviation fuel (SAF), carbon offsetting schemes or other market-based emissions reduction measures.
The forecast comes despite significant improvements in aircraft efficiency over the same period. IBA projects average fleet emissions intensity will fall by around 20%, from approximately 91 grams of CO₂ per revenue passenger kilometre (RPK) in 2025 to 73 grams by 2050.
However, the consultancy expects passenger demand to grow faster than efficiency improvements can offset. Global RPKs are forecast to increase by 134%, from 9.25 trillion in 2025 to 21.65 trillion in 2050.
Fleet renewal is expected to play a major role in reducing emissions intensity, with newer aircraft offering lower fuel burn than the models they replace. Even so, IBA forecasts the global commercial passenger fleet will almost double in size, growing from around 29,800 aircraft in 2025 to more than 56,000 by 2050.
Archie Brown, senior analyst at IBA, said efficiency gains from fleet renewal would continue to reduce emissions on a per-passenger basis but would be insufficient on their own to bring down total emissions as air travel demand grows.
He said achieving the aviation industry's longer-term decarbonisation goals would require wider adoption of sustainable aviation fuels, further operational improvements and supportive policy measures.
Under IBA's baseline scenario, zero-emission aircraft are not expected to enter commercial service in meaningful numbers until after 2046. By 2050, they are forecast to account for around 0.3% of the global passenger fleet, with operations largely limited to local and regional routes.
IBA said its analysis is intended as a baseline projection rather than a net-zero pathway, combining aircraft delivery and retirement forecasts with assumptions around passenger demand, utilisation and load factors. Dedicated freighter aircraft are excluded from the study.
