Growth and jobs or a net zero nightmare? Why there's so much opposition to Heathrow's third runway

As any weary traveller knows, an over-busy airport can be hellish.  But the environmental consequences of expanding them are huge. 

Heathrow Airport’s third runway proposal – last updated in 2019 – required lowering the M25, rerouting rivers and compensating thousands for noise and air pollution. 

Delayed by environmental legal challenges, the plans would have seen aviation emissions increase by seven million tonnes per year.

Yet chancellor Rachel Reeves is reportedly set to throw her support behind the controversial expansion, and to greenlight scaling-up projects at Gatwick and Luton. 

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A possible third runway has been slammed by environmental groups as “catastrophic”, “desperate” and “hugely irresponsible”. There are currently no planning permission requests in for the third runway, but with government support it is highly likely the airport would submit one. 

Asked about it in the House of Commons on Monday (20 January), the chancellor declined to “comment on leaks”.

“But what I would say is this government is absolutely committed to growing our economy and making this a great place for business to invest and trade in,” she added. 

So what will expanding Heathrow really mean?

Campaigners are near-unanimous in their opposition to the plan. Building Heathrow’s third runway would increase carbon emissions by seven million tonnes – roughly equivalent to Uganda’s entire carbon footprint.

“A decision to green-light another runway at Heathrow would be hugely irresponsible in the midst of a climate emergency,” said Jenny Bates, transport campaigner at Friends of the Earth.

“Not only would these expansions bring worse air pollution and noise disturbance for local people, approving them would also contradict the government’s own climate advisors, who say that expansion should not go ahead without a proper national plan to curb emissions from the sector and manage passenger numbers.”

Expanding airport capacity would likely negate emission cuts from the government’s clean-power measures.

“Expanding air traffic is incompatible with our legally binding climate targets [net zero by 2050],” said Finlay Asher, an aerospace engineer and a member of decarbonisation advocacy group safe landing. 

Asher “takes pride” in his job. But airport expansion plans are not the way forward, he says. That’s “desperate, short term thinking” – and there’s no carbon budget available for it.

The Climate Change Committee (CCC) is clear on this count: “There should be no net airport expansion unless the carbon-intensity of aviation is outperforming the government’s emissions reduction pathway and can accommodate the additional demand”.

This dilemma has divided Labour. Keir Starmer voted against a third runway in 2018, the same year that he described the climate crisis as the “single biggest problem we face”.

Energy secretary Ed Miliband – who is responsible for keeping the UK on track with its climate goals – has previously opposed the plans. 

Mayor of London Sadiq Khan told the London Assembly just last week he “wouldn’t hesitate to launch with partners and colleagues another legal challenge” against plans for a third runway.

Will the Heathrow third runway plan actually deliver growth? 

Rachel Reeves is gunning for growth – and some forecasts suggest airport expansion will deliver 70,000 jobs and an additional £147bn contribution to the economy by 2050. 

But experts have cast doubt on this version of events, because increased capacity could disproportionately benefit a small number of frequent flyers on international airlines. Local businesses and job creation may see minimal impact. 

Aletha Warrington – head of aviation at climate group Possible – described approving expansions as a “catastrophic misstep”.

“This would deliver a huge increase in emissions, while failing to deliver economic growth. 

“Expanding airports hurts us all, but only benefits a tiny minority. This will just encourage the small group of frequent flyers who take most of the flights, further worsening the UK’s huge tourism deficit.”

Instead, Warrington called for better investment in affordable, low carbon buses and trains – “the everyday connectivity we all rely on”.

Johann Beckford, senior policy adviser at Green Alliance, also cast doubt on the government’s ‘growth’ rationale.

“Airport expansion isn’t a growth strategy. Business travel and jobs at airports have both been declining,” he said. “Rich frequent fliers are likely to benefit from airport expansion, while poorer communities near them have to deal with increased air pollution and noise.”

Decarbonising aviation effectively must be the goal, says Asher. 

“The aviation industry is at a crossroads. Our current flightpath involves continued growth: more flights, bigger airports and rising emissions. On another route lies a bold transformation toward alternative ways of flying. The chancellor’s vision pins its hopes on the former.”

Instead of expansion, Asher calls for investment in zero carbon aircraft delivering “greener, cleaner and quieter flights”.

“The skies are calling for change. Let’s take advantage of the opportunity to lead,” he said.

“No carbon flights” and sustainable aviation fuels promise to reduce aviation’s carbon footprint by using innovative technologies and biofuels. However, sustainable aviation fuels (SAFs) currently account for less than 1% of aviation fuel usage, causing some environmental groups to question their viability.

SAFs “sound good” until you scrutinise them, Anna Hughes, of Flight Free UK, told Big Issue last year. “It’s a gimmick,” she added.

“We need to reduce the amount we fly. But of course, the government is so reluctant to tell people that.”

Either way, the debate between the need for growth and the race to net zero is only getting more complex for the Labour government. With the world heating up fast, the stakes couldn’t be higher. 

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