Airport expansion plans backed by the government are putting the UK’s net zero target in “serious jeopardy”, MPs have warned.

Without new safeguards, proposals to enlarge airports including Heathrow and Gatwick could push the UK over its carbon budgets, according to a report from the cross-party Commons environmental audit committee.

The MPs said ministers must set out how they are going to meet climate, environment and biodiversity targets while pursuing significant airport expansion and before any of the projects break ground.

Their report found that government policies were insufficient to cut carbon emissions from the aviation sector in line with targets. It said demand for air travel was expected to rise, further putting the reduction plans in “serious jeopardy”.

Keir Starmer, the prime minister, and his chancellor, Rachel Reeves, have approved airport expansion in a desperate search for economic growth.

However, the committee said: “The government has not demonstrated that the economic growth from airport expansion provides enough benefit to outweigh the negative climate and environmental impacts it will lead to.”

The report also said ministers had ruled out measures to manage demand for aviation, such as limiting the number of flights. The MPs also warned that uptake of sustainable aviation fuel might not help cut emissions because it was not yet being used or produced on a commercial scale. Last year, Air New Zealand scrapped its 2030 decarbonisation target, blaming difficulties in securing sustainable fuel.

The expansion schemes are expected to start before the government updates its national policy statement on airports, released in 2018. The MPs said this meant the government was avoiding scrutiny and relying on “an outdated policy framework which is inconsistent with its objectives”.

Toby Perkins, the Labour chair of the committee, said: “Meeting our decarbonisation targets is already a major challenge. Expanding airport capacity is likely to make that task much harder. Under the government’s existing ‘jet zero’ strategy, expanding airport capacity is likely to put net zero at serious risk, unless it is accompanied by a serious strategic approach to increasing the pace of decarbonising aviation.

“Having ruled out the kind of demand management measures likely to seriously reduce emissions, ministers need to make clear what alternative tools they are willing to use to ensure targets are met.”

Alethea Warrington, the head of aviation at the climate charity Possible, said: “This is the final nail in the coffin for the government’s case for airport expansion. The government’s scrutiny committee has made it clearer than ever that airport growth is a bad option for Britain, and that the government simply doesn’t have any economic evidence to justify the environmental devastation this would cause.

“The government must listen to the experts, scrap this reckless agenda of airport expansion, and instead invest in the everyday journeys which really matter to millions of us.”

A Department for Transport spokesperson said: “The transport secretary has launched the review of the airports national policy statement – a significant step in advancing plans for a third runway at Heathrow airport, which will drive economic growth and create jobs, delivering on our plan for change. We have been clear that airport expansion will only go ahead if it aligns with our legal obligations on climate change, including net zero, and we will be seeking advice from the independent Climate Change Committee to inform the review.”