The government's climate advisers have concluded that the proposed third runway at London Heathrow cannot be sanctioned under current UK climate policies and should only be allowed to go ahead if airlines accept financial responsibility for reducing the environmental impact of additional flights.
Their assessment highlights a gap between the expansion plans for Britain’s busiest airport and the national commitments to cut greenhouse gas emissions. The advisers said that without stronger measures to control aviation emissions, approving the runway would be inconsistent with the policies intended to meet the country's climate targets.
"Pay for cleaner flying," the report recommends in broad terms, signalling that carriers should bear the costs of cleaner technology, sustainable fuels or other measures to limit the carbon footprint associated with increased capacity. The advisers argued that relying on existing policies and market signals is insufficient to keep aviation emissions in line with the government's broader climate goals.
The finding places further pressure on ministers who must weigh economic and connectivity arguments for the expansion against environmental obligations. It also places the spotlight on airlines, which would face new expectations to invest in decarbonisation if the runway is to win backing under the advisers' conditions.
Government officials will have to consider whether to strengthen aviation-specific policies, such as introducing tighter market-based mechanisms, mandates for cleaner fuels or obligations that require airlines to compensate for the emissions linked to growth. The advisers' warning is likely to shape debates between industry groups, environmental campaigners and policymakers as the expansion decision proceeds.