Britain’s move to “net zero” carbon and the declaration of a climate emergency in parliament will be “given careful consideration” in deciding whether to grant a review of Heathrow airport’s expansion, the government has said.

The new approach falls well short of any commitment to review Heathrow’s expansion, but means the decision on whether to grant campaigners’ request for a review will include the net zero target and the climate emergency among its criteria.

Green campaigners welcomed the pledge, which came in a letter to environmental group Plan B. Tim Crosland, director of Plan B, said: “We’re pleased to see the government is taking seriously our request to review the expansion of Heathrow airport. The government can either take the necessary action to avoid climate breakdown or it can stick to business as usual and expand aviation, but it can’t have it both ways.”

The letter is also one of the first indications of how the net zero target, recommended last week by the committee on climate change, and parliament’s vote to recognise a climate emergency, may be taken into account in future by civil servants giving advice to ministers on key issues such as transport and infrastructure.

Green campaigners will be pressing the government to review existing policies on these issues in the light of the committee’s view that it is “necessary” for the UK to be net zero by 2050, arguing that policy decisions made previously are now invalid. Plan B wrote to the government on 2 May requesting a new review of the airports national policy statement (ANPS), under which the Heathrow expansion will take place, making that argument.

In the letter to Plan B, seen by the Guardian, Caroline Low, the director of Heathrow expansion and aviation and maritime analysis at the Department for Transport (DfT), wrote: “I can confirm that the department will carefully consider this request [for a review of the airports national policy statement, which includes Heathrow].

“As well as giving careful consideration to the net zero report and the declaration of environment and climate emergency, mentioned in the request, it may be necessary to consider the committee on climate change’s recommended policy approach for aviation … and any relevant decisions taken by the government in the coming months as a result.”

A plane takes off over a road sign for Heathrow airport in London. Photograph: Kirsty Wigglesworth/AP

A DfT spokesperson said: “The expansion of Heathrow received overwhelming support from MPs because it would provide a massive economic boost to businesses and communities the length and breadth of Britain, all at no cost to the taxpayer and within our environmental obligations.

“We take our commitment to the environment very seriously and we will give careful consideration to the net zero report. No decision has been taken to review the ANPS, however we are legally obliged to consider requests like this one.”

Last week, a case brought by Plan B and others that ministers must take the Paris climate agreement into account in considering Heathrow expansion was thrown out by the high court.

Officials are also understood to believe that any decisions on the request for a review are some way off because the climate change committee will not produce its policy approach on aviation until later this year, so no decision on how to take its findings into consideration will be made until then. This means no recommendation to the secretary of state is likely until next year.

Crosland responded: “The government can split hairs if they want, but the situation is too serious for that. Parliament approved Heathrow expansion on the basis of very different circumstances to those which now prevail. It’s just common sense the position calls for reconsideration. You can’t declare an emergency and then act like nothing’s changed.”

The net zero report produced by the CCC was hailed as one of the biggest developments in the UK’s approach to climate change in the last decade. The recommendations will require vast changes to all aspects of the British economy, encompassing citizens, consumers, businesses, government and civil society.

MPs passing the vote on a “climate emergency” also marked a historic moment in British politics, as it would, if implemented effectively, require the government to have regard for the climate in policy decisions across the board.

Siân Berry, the co-leader of the Green party, said: “In this age of climate emergency, Heathrow expansion very clearly cannot go ahead. We need the government to acknowledge the emergency situation that previous policy choices have created. All building of new fossil fuel infrastructure has to end. That means banning fracking, stopping new road building and of course ending Heathrow expansion.”