It was bad enough when David Cameron told his officials to cut the 'green crap' but his successor just sent out a massive signal she's not remotely bothered about global warming.

It was, with the possible exception of appointing Boris Johnson as Foreign Secretary, the starkest statement of intent made by Theresa May in her first 24 hours in Downing Street.

Amid mounting concern that the world must do much more to prevent the worst effects of climate change, our new Prime Minister decided to abolish the UK’s climate change department.

In 2013, in the teeth of an energy bill crisis, David Cameron reportedly said it was time to “get rid of all the green crap”. That statement can be interpreted in two ways: cut everything green because it’s all crap or cut the green policies that are crap and keep those that work.

To be fair to the departed Prime Minister, while support for renewable energy was slashed under his watch – as the fossil fuel industry continued to benefit from lavish subsidies – there was still significant funding to help offshore windfarms and biofuels, for example. About half the power generated by the giant Drax power station currently comes from biofuels thanks in part to Government help.

And Cameron never decided climate change was such a trivial issue that it did not deserve its own Government department.

May’s priorities could not be more clear. The clues are in the titles. 

Britain now has a Secretary for Exiting the European Union – a very sensible move if Brexit is inevitable – a Secretary for International Trade and a Secretary for Business, Energy and Industrial Strategy. You wouldn't know it, but the latter will be responsible for dealing with climate change.

The majority of ‘experts’ warned leaving the EU would cause serious economic problems for the UK and, potentially, the rest of the world. Michael Gove, sacked from the Cabinet, dismissed their warnings, but May most certainly did not.

So, it appears, Britain will concentrate on one thing for the next four years – preventing the economy from disappearing down the toilet.

Fear of a Brexit apocalypse seems to have prompted May to sacrifice the fight against climate change in the hope of avoiding a recession that would almost certainly see her removed from office – by her own side, if not Labour.

But, make no mistake, this could be a historic blunder of global proportions.

The UK and Germany drove much of the European Union’s world-leading environmental policies. Only last month, the then Energy and Climate Change Secretary Amber Rudd announced the UK would reduce greenhouse gas emissions by 57 per cent by 2030.

It was target widely praised by environmentalists with Hugh McNeal of industry body RenewableUK hailing the “clear signal” that the UK would “show bold leadership on carbon reduction”.

Rudd is regarded as a genuine ‘green blue’, a Conservative who understood the pressing need to deal with climate change – even if it meant making an announcement that sounded better than it actually was ahead of the Paris climate summit.

The new Home Secretary was “a driving force” behind international deal agreed at Paris last December, according to Professor Corinne Le Quéré, director of the Tyndall Centre for Climate Change Research at the University of East Anglia.

Asked about the prospect of occasional climate sceptic Boris Johnson becoming Prime Minister before May’s coronation, Rudd stressed she would be “very, very clear” and “very vocal” in holding Britain’s next leader to account on the issue.

But as she struggles, and likely fails, to deliver May’s ambitions to reduce immigration to tens of thousands, she may find that commitment slipping down her agenda.

Now at international meetings, world leaders expecting to meet the UK climate change secretary will instead be introduced to the Business Secretary. 

There are worse people than Greg Clark who could have been in this role. The UK’s new Environment Secretary Andrea Leadsom, on becoming Energy Secretary last year, decided to make her first question to officials “Is climate change real?” She claimed she had since been convinced but it shows an alarming lack of knowledge and interest in the world’s most pressing issue.

Clark was hailed as an “excellent appointment”, someone who “understands climate change” and the “the benefits of Britain developing a low-carbon economy” by Richard Black, director of the Energy and Climate Intelligence Unit.

But in a Cabinet packed with people with dubious voting records on climate change and funding links to sceptics, Clark may find projects that do not immediately turn a profit get short-shrift.

And he may come under pressure from companies with the mindset of Volkswagen -- which "cynically" deceived the authorities to enable their cars to pump out exhaust fumes at levels harmful to human health – to push for the cutting of ‘red tape’ and ‘Brussels-style bureaucracy’ that hit their profits in the Brave New World of Brexit Britain. 

That this red tape helped reduce the number of premature deaths caused by the air pollution may be overlooked, as it was during the referendum campaign.

The UK’s focus on the need to survive Brexit may be sensible. But the risk is we become dangerously short-sighted.

Stripped of a leader on climate issues, the world’s efforts to prevent global warming – already half-hearted at best – may falter. The talk at Paris was limiting global warming to well below 2 degrees Celsius, but the actual pledges could see temperatures rise by more than 3 degrees – perilously close to a scenario so extreme and unpredictable that few experts attempt to predict what the world would be like. If those pledges turn to nothing, our children may find out.

Another possibility is that Britain will be left behind as the world moves to a different kind of economy, one turbocharged by the virtually free power that mass renewable energy is already starting to deliver. In Germany, customers have even been paid to consume electricity.

The UK would then be forced to belatedly catch up by buying technology from other countries – many of our windturbines already come from Denmark.

A future Britain could be a bleak place: lashed by devastating Atlantic storms, sweltering in heatwaves that kill the young and the old in ever-increasing numbers, a countryside left scarred by disused fracking wells as fossil fuel companies go bankrupt.

But I don’t think this will happen. I actually think we – the UK and the world – are too sensible for that. We will wake up just in time. We will.

I just hope those experts are wrong and that Brexit won’t be so bad the British government decides to think of nothing else.