While the UK has been a global leader in the fight against climate change, it has shown signs of faltering in its commitments since the Brexit referendum.

And the added political turmoil caused by an indecisive general election now risks a dangerous drift on the issue of our age, just as scientists are warning that time is starting to run out to prevent the worst effects of global warming.

Under Theresa May, the Government adopted ambitious targets to cut greenhouse gas emissions but then delayed publication of the legally required plan to achieve them, prompting ClientEarth – a group of activist lawyers who are taking ministers to court for a third time to force them to improve their latest attempt at an Air Quality Plan that abides by the law – to threaten to sue.

The deal between the Conservatives and the Democratic Unionist Party, which together would command a slim majority, will enable Ms May to stay in Downing Street for now, but the uneasy political alliance could easily collapse, potentially causing a fresh election. The DUP is a party that once appointed an environment minister who does not believe humans are responsible for climate change and fresh election would see further drift.

Ms May was reportedly insisting she would not stand down but looks unlikely to last, given her disastrous decision to call the election, lacklustre performance during the campaign and the Tories’ history of ruthlessness with failure.

Her potential replacements include people with strong track records on taking climate science seriously and others set in the Donald Trump mould.

Boris Johnson, the Foreign Secretary, has questioned whether climate change is real; Michael Gove, the former Justice Secretary, has talked about ripping up environmental regulations after Brexit; and Sir Michael Fallon, the Defence Secretary, once railed against “unthinking climate change worship” that had “damaged British industry” while he was energy minister.

But Amber Rudd, the Home Secretary, who stood in for Ms May during the BBC leaders debate, is regarded as a genuine “green blue”, a politician capable of seeing past the politicisation of global warming, understanding the science and the need to take action. During the last Tory leadership contest, she promised to hold Mr Johnson’s feet to the fire if his apparent climate science denial became a problem.

And Philip Hammond, the Chancellor, has said it is “wholly consistent with Conservative values to tackle the challenge of climate change”, quoting Margaret Thatcher as saying “the last thing we want is to leave environmental debts for our children to clear up”.

He may have a low profile, but Greg Clark, the Business Secretary, is highly regarded within environmental circles and could be just the safe and competent, if rather boring, pair of hands the UK needs in these tumultuous times.

It has been noted by others that many leading Tory Brexiteers are also climate science sceptics or deniers, with some campaigners so close that they share the same address.

Amid the apparently inevitable Tory party infighting, possible attempts by Labour to cobble together an unlikely coalition, and the chance of a weakened government stumbling on for a few months before calling another election, the world keeps turning and warming.

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The most pressing issue for the UK is the publication of the long-delayed but legally required Emissions Reduction Plan, aka the Clean Growth Plan, which will involve making massive and potentially controversial decisions.

Among the most significant involve decarbonising transport – by facilitating the switch to electric vehicles – and heating, most of which is currently done by gas. Norway’s approach to the sort of issues that will be covered in the plan was to announce a complete ban on petrol-powered cars by 2025.

The government must also decide how it will replace ageing coal-fired and nuclear power stations due to come to the end of their working lives in the mid-2020s. Ministers have also promised a 25-Year Environment Plan to help achieve a much-repeated pledge to leave the natural world in a better state than they found it.

Gareth Redmond-King, a former civil servant who is now head of climate and energy policy at environmental group WWF-UK, said it was possible that Ms May would simply reappoint her existing ministerial team and Nick Hurd, the climate change minister, would carry on with his job of producing the Emissions Reduction Plan.

But he added this was “almost hard to imagine”, given the political infighting widely expected to break out.

“That intriguing is going to distract people and the Clean Growth Plan is just not going to be top of people’s agenda,” Mr Redmond-King said. “[Theresa May] is also not going to feel she can stand up to Trump as we have asked her to do. I don’t think anything will change for the better.”

James Orr, Friends of the Earth's Northern Ireland Director, said the Conservatives' decision to carry on in Government with the support of the DUP was alarming.

"Under the DUP leadership, Northern Ireland has become a wild west for the environment. Northern Ireland is the dirty corner of the UK with some of the biggest illegal waste sites and mines in Europe. The pro-fracking DUP is a climate pariah," he said.

“When we need clear leadership they are muddled over Brexit. They want to have their cake and eat it. On the one hand they are active Brexiteers but on the other they are desperate to preserve the economic benefits of ties with Europe.

“Their manifesto had hardly a positive word on the environment and nothing at all on climate change. Theresa May must not allow the DUP to further weaken her already inadequate manifesto commitments to maintain environmental protections and preserve nature.”

Oxfam has been campaigning on climate change as it has become an increasingly pressing issue for many developing countries around the world.

Matthew Spencer, Oxfam GB's director of policy, influencing and campaigns, said he now feared British drift on the issue.

“Whatever the outcome [of the election], the risk is that Britain spends the next few months internally focused, not playing its role in the world – which has traditionally been very positive, both in terms of development and climate action – at a time when there’s a real challenge to climate action coming from the Trump administration and investors are waiting for clarity about the clean energy plan,” he said.

“Both on the international stage and the domestic front, there is some really important government business. The uncertainty of a hung parliament and the Brexit negotiations means we could become very parochial.”

Bob Ward, policy and communications director at the Grantham Research Institute on Climate Change and the Environment, said the Emissions Reduction Plan would be “the big thing that is going to be on the desk of whoever comes in”.

“We are going to need to really accelerate the development of electric vehicles, and there are going to have to be big decisions on how to replace gas central heating systems,” he said.

“Both of these will require significant policy development and are likely to be controversial."

One concern before the election was that Brexit was taking up civil servants time so much it was impacting their work on climate change and environment.

Mr Ward said he suspected that following the election the relevant departments "are going to spend even more time trying to work out our Brexit position".

At stake is the UK’s transition to a low-carbon economy.

Dr Nina Skorupska, chief executive of the Renewable Energy Association, said despite the “uncertain times”, the main parties were all agreed on the need to reduce greenhouse gases, create jobs and cut energy bills.

“The renewable and clean tech industry has been waiting for nearly a year for the release of the Clean Growth Plan and it’s now critical for us that we have a clear commitment and direction, no matter what shade of government,” she said.

However, Ben Caldecott, an associate fellow at liberal Conservative think tank Bright Blue, saw a potential silver lining.

“There is a deep cross-party consensus on the need to tackle climate change and to make our country cleaner and greener. This will be a fertile area for cross-party collaboration in a hung parliament,” he said.