Question to the Department for Transport:

To ask the Secretary of State for Transport, what estimate he has made of the potential reduction in emissions from aviation as a result of reduced stacking in the event of the completion of a third runway at Heathrow airport.

The UK has embarked on an ambitious programme of airspace modernisation, one of the key drivers of which is to reduce aviation’s environmental impact. This programme should allow more direct routing, reduce delays, enable aircraft to climb at a faster rate, and also reduce the amount of stacking.

With regards to Heathrow expansion, the environmental impact of the proposed airspace changes linked to this development, including their likely effect on CO₂ emissions, will be assessed in coming years through the statutory Civil Aviation Authority airspace change process. Therefore there is currently no estimate of the reduction in emissions as a result of modernising Heathrow’s airspace.

The Airports National Policy Statement is also clear that a new Northwest Runway will not receive development consent unless, with mitigation, it can demonstrate compliance with legal obligations on air quality.