MPs from across the political spectrum say the UK prime minister must urge the US president to remain in the global Paris agreement

Prime minister Theresa May must challenge President Donald Trump’s “contempt” for environmental protection and urge him to remain in the global agreement to fight climate change, according to MPs from across the UK’s political parties.

May will meet Trump on Friday in Washington DC and has been warned by MPs that the US president’s approach to global warming could determine whether or not people around the world suffer the worst impacts of climate change, such as severe floods, storms and heatwaves.

In his first few days as president, Trump has already replaced the climate change page on the White House website with a fossil-fuel-based energy policy, resurrected two controversial oil pipelines and attempted to gag the Environmental Protection Agency, the Agriculture Department and the National Parks Service.

Trump, who has called climate change a “hoax” and “bullshit”, has packed his administration with climate-change deniers and his pick for secretary of state is former ExxonMobil boss Rex Tillerson.

“We have grave concerns about the new president’s views on climate change and his reported plans to abandon the Paris agreement,” said the cross-party Environmental Audit Committee (EAC) of MPs in a letter to May. “Climate change is one of the greatest challenges of all time. The scientific evidence is unequivocal.”

The US is the second largest emitter of greenhouse gas emissions and the MPs said Trump’s “approach to reducing emissions could determine whether we, in the UK and people around the world, experience or avoid the worst impacts of climate change.”

Mary Creagh MP, EAC chair, said: “The prime minister should start by telling him climate change is not ‘a hoax’. We’re urging her to impress upon President Trump the importance of global action to tackle this global problem and to continue the US commitment to the Paris agreement.”

Caroline Lucas, a Green Party MP, said: “Donald Trump’s first few days as president have revealed his contempt for environmental protection. Failing to bring up climate change with him would be a dereliction of duty from Theresa May.”

Ed Miliband MP, a former leader of the Labour Party challenged May in the House of Commons on Wednesday: “As the first foreign leader to meet President Trump, the prime minister carries a huge responsibility on behalf of, not just of this country, but the whole international community in the tone that she sets. Can I ask her to reassure us that she will say to the president that he must abide by, and not withdraw from, the Paris climate change treaty?”

May replied: “The Obama administration signed up to the Paris climate change agreement, and we have now done so. I would hope that all parties would continue to ensure that that climate change agreement is put into practice.”

A government spokeswoman added: “The future direction of US climate policy is a matter for the US. But we face shared challenges on energy and have worked closely together on climate change issues. And we hope to see this continue under the new administration.”

May also told MPs she is “not afraid to speak frankly” to President Trump, thanks to the special relationship between the UK and America. But after the release of extracts from a speech May was giving in the US, she was accused of “grovelling” by former business secretary Vince Cable in order to win a trade deal.

One the eve of Trump’s inauguration, when 2016 was declared as the hottest year ever recorded, leading climate change figures urged the president to “make America great again” – and the world safer – by embracing the trillion-dollar green tech revolution. Over 100 UK climate experts also wrote to May earlier in January warning that Trump’s suggestion that he would cut US climate science would leave the world “flying blind” in tackling global warming.

Craig Bennett, chief executive of Friends of the Earth, said: “Trump’s war on our environment has already begun. Silence [from May] is not acceptable – it will simply legitimise the new president’s climate denial.”

Greenpeace UK executive director John Sauven said: “The relationship is only special if the prime minister is prepared to say what Trump wants to ignore. And what May should make absolutely clear is that the UK won’t wind back the clock on progress but will keep striving for a more peaceful and prosperous future.”

On 11 January, before President Trump’s inauguration, Tillerson said the US should remain part of the global climate change agreement, signed in Paris in December 2015. “It’s important that the US maintain its seat at the table,” he said. The danger of climate change is real and “requires a global response”, he said. “No one country is going to solve this on its own.”

But on Thursday, a draft executive order leaked to the media suggested the Trump administration is preparing to order sweeping cuts in funding to the UN and other international organisations, while potentially walking away from some treaties.