The United Kingdom’s independent Climate Change Committee has warned that any expansion of Heathrow Airport would require substantial additional measures to keep aviation emissions compatible with the country’s legally binding climate targets.

The committee said that expanding the airport, including construction of a proposed third runway and additional terminals, could put pressure on the UK’s carbon budgets under current policies. It said aviation would need to become more efficient, increase the use of sustainable aviation fuels and support permanent carbon dioxide removal.

The warning comes as passenger demand for air travel continues to grow. According to the committee, aviation now accounts for about 9% of the UK’s emissions, making reductions in the sector increasingly important for the country’s long-term climate strategy.

The committee has therefore linked any future airport expansion with stronger requirements for airlines to address their emissions rather than relying on reductions from other parts of the economy.

Sustainable aviation fuel is expected to play a role in the industry’s transition, although increasing production and ensuring sufficient supplies remain major challenges.

The committee has also pointed to carbon dioxide removal and permanent storage as another potential component of the strategy. However, the scale and cost of such technologies remain important considerations.

Heathrow has argued that airport expansion should be compatible with both economic growth and the UK’s net-zero ambitions. The debate therefore involves balancing increased aviation capacity with the country’s climate commitments.

The latest assessment adds climate considerations to the wider debate over the future of one of Europe’s busiest airports and highlights the challenge governments face in expanding transport infrastructure while reducing greenhouse-gas emissions.