Leading climate scientists who created Greater Manchester’s carbon neutral by 2038 commitment are urging Andy Burnham to unequivocally reject new drilling in the North Sea.

In a letter to the prime minister they said he, as mayor of Greater Manchester, had unveiled one of the UK’s most ambitious local climate programmes that tackled housing, green growth and public transport.

Reports over the weekend continued to suggest Burnham was set to give the green light to controversial new drilling in the North Sea by approving the Jackdaw and Rosebank oilfields, which were given approval under the Conservatives but put on hold by legal action. The ruling in court said a more detailed assessment of the environmental impact was required to take into account the effect on the climate of burning any fossil fuels extracted.

Prof Kevin Anderson and scientists from the Tyndall Centre at the School of Engineering at the University of Manchester, who wrote the open letter to the prime minister, said it was “with considerable concern” that they had read reports suggesting his government intended to approve the further development of the Rosebank and Jackdaw oil and gasfields.

To do so would send a signal around the world that the UK was backtracking on its international climate commitments, they said.

If the reports were accurate that he intended to give the go ahead to drilling at Jackdaw and Rosebank, the scientists wrote, “they represent a profound departure from the principles you promoted as Mayor of Greater Manchester”.

Labour made a manifesto promise that no new oil and gas licences would be issued, but Jackdaw and Rosebank were already in the system at the time of the last general election. A consultation on Jackdaw will finish on 8 August.

With extreme heat and wildfires across the UK and Europe this summer, the academics said the evidence showed global emissions must be cut by 8% every year if the world was to meet the upper limit of a maximum of 2C of heating in the Paris climate agreement.

Anderson and his colleagues urged Burnham to adhere to commitments he made when announcing the Greater Manchester carbon neutral by 2038 policy.

They undertook the carbon budget analysis that underpinned the target championed by Burnham in 2024, when he said Greater Manchester could be front and centre of the green industrial revolution.

At the time Burnham said he needed greater powers than those of a mayor to deliver the pace of change required to tackle the climate crisis.

Now he has those powers, the scientists who helped him create the carbon neutral plan in Manchester said he must not abandon unequivocal scientific evidence in the face of short-term political pressure.

“The scientific evidence has only strengthened since those earlier commitments were made,” the letter said.

“Global temperatures have already risen to the lower limit of the Paris Agreement’s temperature range (1.5°C). Extreme weather events are becoming increasingly evident across the UK, most vividly the widespread moorland fires driving air quality to unsafe levels in Greater Manchester.”

Remaining global carbon budgets, which give policymakers headroom for action, continue to shrink rapidly. If governments are to respect even the weaker 2C interpretation of the Paris Agreement, global carbon dioxide emissions must now fall by almost 8% every year, starting immediately, they said.

“Against that backdrop, approving the further development of oil and gasfields cannot be reconciled with the UK’s repeated commitment to honour its international climate obligations,” the letter said.

Anderson and his colleagues said any approval of new drilling would send the wrong signal to the rest of the world.

“It would suggest that, on climate change, the UK is prepared to step back from obligations it has repeatedly urged other nations to uphold.”

The letter urged Burnham to show the same commitment to evidence and political courage that characterised his leadership in Greater Manchester in response to pressure to open up new drilling in the North Sea.

“Future generations will not judge governments by the ingenuity with which they justified expanding fossil fuel production,” the scientists wrote. “They will judge whether, when faced with unequivocal scientific evidence and clear international commitments, they had the courage and compassion to act in a manner consistent with the obligations they had freely entered into.”