UK airports are planning to expand almost three times faster than the government's climate change advisers say is sustainable, according to research by Sky News.

Our analysis of the "masterplans" for 21 of the country's biggest airports show they intend to add 192 million passengers to the 286 million that already use their terminals over the next 10-20 years.

That's a growth of 67%.

It far exceeds the ceiling of "at most 25%" that the Committee on Climate Change has told the Department of Transport is the limit for sustainable growth if the UK is to meet its commitment for net-zero greenhouse gas emissions by 2050.

Lord Deben, the chairman of the committee, told Sky News: "The fact is, it is the law that we have to keep our emissions down.


"I don't want to stop people having holidays. That would be the last thing I want.

"But you can't have a holiday at the cost of the Earth. If you want to have holidays the industry has to find ways of having holidays without destroying the Earth."

Image: Southampton airport hopes to grow from two million to five million passengers by 2037

Heathrow, with its plan for a controversial third runway, accounts for 50 million extra passengers.

But even if Boris Johnson scraps the runway - and he vowed to lie in front of the bulldozers when he was elected as a west London MP in 2015 - our figures show the government faces a massive challenge in curtailing passenger numbers.

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Three-quarters of the anticipated passenger growth is at other airports.

Gatwick, the UK's second-busiest airport, hopes to add 24 million passengers to the 46 million already using its terminals.

But our research reveals even small airports have big plans.

Southampton hopes to expand from two million to five million passengers by 2037 - an increase of 151%.

Image: Gatwick hopes to add 24 million passengers to the 46 million already using its terminals

But the biggest expansion of all is at Doncaster Sheffield airport, where passenger numbers could growth from 1.2 to 7.2 million - that's up 490%.

Belfast City airport wants to almost double the number of passengers to four million over the coming years.

Brian Ambrose, its chief executive, defended the growth, adding that the local economy stood to benefit.

"We are an island off an island. Flying is essential," he said.

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"We are fortunate that we have airlines with more modern aircraft with fewer emissions. If we grow with that kind of product we can grow and reduce our emissions at the same time."

According to the Committee on Climate Change, aircraft using UK airports produce 37 million tonnes of greenhouse gas a year.

But fuel efficiency is expected to improve by just 1.4% a year and low-carbon biofuels are expected to make up only 10% of aircraft fuel in 2050.

That's nowhere near enough to compensate for the planned-for increase in passengers.

Controls on numbers, perhaps with a levy on frequent flyers or a carbon tax, look inevitable.

Lord Deben said: "The overarching matter is that we are steadily destroying our ability to live on this Earth.

"The idea that something is good for the economy only stands up if the economy itself is properly protected.

"That is what we are doing in our net-zero plan which is now the law. Because we need it to make sure this planet is available for future generations.

"The thing that is good for the economy are the green changes that we are making in this country and are leading the world on."

Green groups and the London mayor will challenge Heathrow's expansion plans in the Court of Appeal on Thursday. Their case was dismissed by two High Court judges in May.

Grant Shapps, the transport secretary, has said he is separately looking at whether "the figures stack up" to justify the third runway.