UK government is likely to be challenged by its own climate change advisory body on its decision to approve a third runway at Heathrow and permit a doubling in air travel by 2030.

The Committee on Climate Change believes that the rapid expansion of air travel is inconsistent with the Government’s legally binding commitment to cut overall carbon dioxide emissions by 80 per cent on 1990 levels by 2050.

It believes that allowing aviation to expand at the rate proposed by the Government could place an unacceptable burden on other industries to achieve the cut.

The committee is also concerned that the expansion of air travel will undermine efforts to persuade developing countries to agree emissions cuts at the UN summit on climate change in December.

When approving the third runway in principle in January, the Government made it conditional on the aviation industry meeting its own target of cutting emissions to 2005 levels by 2050. Ministers avoided using the 1990 baseline because this could have forced airlines to halve the present number of flights.

Air passenger numbers grew from 102 million in 1990 to 240 million in 2007 and are due to reach 470 million by 2030.

In a letter published today, the committee says that if aviation emissions are at 2005 levels in 2050 the rest of the economy will have to make 90 per cent cuts to achieve the overall 80 per cent emissions reduction target.

The committee will publish a review of UK aviation and its impact on climate change on December 8, one week before Gordon Brown and other world leaders are due to sign a global treaty on cutting emissions.

In an interview with The Times David Kennedy, the committee’s chief executive, said: “It wasn’t specified in our terms of reference but we could take it upon ourselves to talk about Heathrow in our UK aviation review.”

He said that the review would discuss what level of increase in air travel could be accommodated by Britain’s legally binding carbon budgets.

“Can you double demand? You can imagine a world where you have more people flying because you have efficient planes running on biofuel. But whether these things are plausible, we will report back in December.”

Virgin Atlantic is among a handful of airlines that have experimented with using a tiny percentage of biofuel mixed with conventional jet fuel in test flights without passengers. However, industry analysts believe that concerns about safety and a lack of sustainable biofuel sources mean that it is likely to play only a minor role in powering future aircraft.

In its letter to the Government today the committee says that airlines cannot rely indefinitely on offsetting their emissions by buying allowances.

The letter says: “The aviation industry should also plan for deep cuts in gross CO2 emissions.” It adds that unless a global deal is reached on cutting aviation emissions, airlines will account for one fifth of all CO2 emissions by 2050.

Vicky Wyatt, a Greenpeace climate change campaigner, said that any government would find it almost impossible to build a third runway at Heathrow if it followed the committee’s advice.

“Even without the proposed expansion of aviation, the UK industry is going to find it very hard to offset its emissions through trading carbon, not least because we already fly more than any other nation on Earth and other industries such as the power sector would have to reduce their emissions even further to create room for the aviation sector to grow even more. Electricity consumers could end up footing the bill.”

The Conservatives have said that they would cancel plans for new runways at Heathrow and Stansted and would also oppose the expansion of Gatwick. However, the party has refused to say whether it would limit the overall growth of UK aviation.