The expansion of Heathrow would be an expensive disaster for Britain and the world. Burnham needs to block it | George Monbiot
A third runway at Heathrow would impose massive economic and environmental costs that far outweigh its benefits, according to government analysis, yet ministers continue to support the project. The Department for Transport calculated the construction would cost between £23.4bn and £62.5bn, yet add only 0.03% to 0.05% to GDP—far less than the airport's claimed 0.43%—whilst causing major harm to the health of up to 3 million people. Transport Secretary Andy Burnham has signalled ambivalence, calling the project "contested" and suggesting it is principally a matter for London.
The climate implications are particularly severe. The Climate Change Committee warns that Heathrow's expansion alone would cause more carbon emissions by 2054 than any other sector of the economy. The true heating impact of aviation is substantially underestimated in policy: when accounting for compounds released in the upper atmosphere, flying's warming effect is 517% greater over a 20-year period than CO2 alone. Proposed sustainable aviation fuel solutions—whether biomass-based or synthetic—are equally problematic; biomass would require half of all UK agricultural land, whilst synthetic fuels have massive energy demands.
- Third runway would cost up to £62.5bn yet add minimal GDP growth
- Project would harm 3 million people's health whilst causing massive carbon emissions
- "Sustainable" fuel solutions would either destroy farmland or require vast energy inputs
Both sides, in good faith
The strongest fair case each way — we don't pick a winner.
The case for
Heathrow's expansion would strengthen Britain's economic competitiveness by improving international connectivity for businesses and consumers, with lower ticket prices through increased capacity and competition. Modern aircraft already emit far less per passenger than older ones, and the project provides time for sustainable aviation fuels and efficiency improvements to mature at scale whilst the UK pursues decarbonisation alongside growth. Construction and operation would generate substantial employment and economic activity, whilst capacity is necessary to compete with continental rivals like France and Germany.
The case against
Government analysis shows the project would cost tens of billions whilst delivering only 0.03-0.05% GDP growth—negligible returns that cannot justify such expenditure. Aviation's true climate impact is vastly understated in policy: accounting for upper-atmosphere compounds, flying's warming effect is 517% greater than CO2 alone, and Heathrow's expansion would generate more emissions than any other economic sector by 2054. Proposed solutions are illusory: sustainable aviation fuels would require half of all UK agricultural land or enormous energy inputs, making genuine decarbonisation impossible at expanded capacity.