Heathrow expansion could cost Britain up to £62.5bn, George Monbiot argues

George Monbiot is urging Greater Manchester mayor Andy Burnham to oppose Heathrow expansion, arguing that a third runway would bring major economic and climate costs for Britain.

The UK Department for Transport estimates that the project could cost the country between £23.4bn and £62.5bn. Its analysis put the GDP gain at 0.03% to 0.05%, compared with the 0.43% figure previously cited by Rachel Reeves from a report commissioned by Heathrow.

The department also said the runway could cause major harm to the health and wellbeing of up to 3 million local people. Expansion remains official government policy, but Burnham described it as “contested” and principally a matter for London and London MPs.

Completion date moved to 2039

Heathrow has delayed the project again. After saying last year that its plans were ready to proceed, the airport acknowledged that construction would take four years longer than previously claimed; the revised estimated completion date is 2039.

Aviation’s climate contribution

Monbiot cites the Climate Change Committee, which says that by 2050 almost all CO₂ emissions could come from aviation, while Heathrow’s expansion would produce more carbon emissions by 2054 than any other sector of the economy.

He also refers to research in Atmospheric Environment which found that aviation’s wider effects could increase its warming impact by 115% over 100 years and by 517% over 20 years.

Limits of alternative fuels

The Royal Society estimates that meeting current UK aviation demand with energy crops would require about half of the country’s agricultural land. Synthetic fuels, it found, would require five to eight times the UK’s entire current renewable electricity capacity.

If Heathrow expands, UK passenger numbers are forecast to rise from 299 million in 2025 to 491 million in 2050. Monbiot advocates a frequent-flyer levy: in 2024, 48% of England’s population took no flights, while 5% took at least five overseas flights and accounted for 33% of all such journeys.