At the very least, those concerned about global warming and the green economy can take heart from the fact that David Cameron has not appointed a climate change sceptic as secretary of state for the Department of Energy and Climate Change (he has form). Amber Rudd says climate science is “compelling” and has spoken strongly of the need for a strong deal at a crunch UN summit in Paris in December.



But there appears to be much more to be optimistic about than that, with her appointment meeting with broad approval from green business and campaigners. Firstly, she was climate change minister for almost a year before the election, meaning she can hit the ground running in the tortuous but crucial climate change negotiations.

One government insider told me she is “really green and no-nonsense” and can get things done, adding that her past experience as an investment banker and businesswoman will be useful in delivering the huge investment needed in the energy sector.

The key will be whether energy and climate change policy is run from Decc or the Treasury. Rudd was first elected as an MP in 2010 and rose quickly, becoming a parliamentary private secretary to chancellor George Osborne and then assistant whip. Being relatively close to the chancellor will be vital in getting Rudd’s energy policies through, but another former Decc minister and windfarm opponent, Matt Hancock, is said to be closer to the chancellor.

Rudd, MP for Hastings and Rye, frequently quotes Margaret Thatcher when asked about the Tory attitude to climate change. “The first world leader to speak about climate change at the UN was Margaret Thatcher and she of course was a scientist and the science is completely compelling. If I’m challenged on it by any of my own party – although I haven’t been – I would say ‘I’m a Thatcherite – aren’t you?’” she told Business Green in 2014.

So, despite having been barred by Michael Gove from going the UN climate talks in Peru in December, it seems likely Rudd will push hard for a deal to cut emissions.

But her admiration of Thatcher may well prove more divisive in other areas. She is a strong believer in business and markets as drivers of change, rather than regulation and government intervention. The balance between those two approaches is at the heart of arguments about how to fight climate change and also how to ensure the UK’s energy system is simultaneously low-carbon, affordable and secure.

A looming problem is the much-delayed EDF nuclear power station that Rudd backs. Despite the promise of vast subsidies, the deal is still not finalised. Rudd’s instincts will not be to throw even more billpayers’ money at the problem, but losing the station would leave a big hole in the UK’s energy plans.

Just before the election, Rudd said: “We will continue to take action to protect the environment as part of our long-term economic plan for green jobs and growth. However, we will do it in a way that represents the lowest possible cost to consumers - through bearing down on the costs of green energy, driving greater innovation and working with business to deliver solutions.”

Championing the fast-growing green economy will be vital - it was barely spoken of by the Tory part of the coalition. But the “lowest possible cost” promise is directly contradicted by the Conservative’s own manifesto, which pledged to halt subsidies to new onshore wind farms, the cheapest renewable energy available.

Rudd’s business-centred approach will also be challenged by the need to continue to increase the energy efficiency of the Britain’s cold and leaky homes. It’s the cheapest way of all to cut carbon emissions and tackle fuel poverty, but the coalition’s market-based approach, the Green Deal, was a complete flop. Most insulation was delivered by forcing the big energy companies to do it. A Tory aversion to regulation also rules out improving building regulations to provide warmer homes. However, sources have told the Guardian that Rudd does place a high priority on delivering energy efficiency.

The attitudes of Rudd’s ministers will be important but there could scarcely be less unity of purpose than there was under the coalition, where windfarm-averse Tory ministers were sent into Decc to fight LibDem energy secretary Ed Davey.

Greenpeace called Rudd’s appointment hopeful while Richard Black, director of the Energy and Climate Intelligence Unit, said: “The appointment of Rudd is significant in that it shows that the Conservative Party leadership retains its commitment to policies based on sound climate science.”

Whether that commitment survives better than Cameron’s pre-2010 election slogan of “vote blue, go green” remains to be seen.

Updated 15:00: Liz Truss remains Environment secretary; Greg Clark replacing Eric Pickles at Communities and Local Government; Oliver Letwin to run Cabinet Office.

Liz Truss, who was promoted to environment secretary after Owen Paterson’s sacking in July 2014, is to continue in the post. Truss has been an enthusiastic backer of British farmers and food but has been much less vocal on the natural environment.

Truss has said the highly controversial badger cull will be rolled out more widely. Most farmers support the cull, aimed at curbing tuberculosis in cattle, but scientists have declared it ineffective. The Department of Environment, Food and Rural Affairs was heavily cut in by the coalition and, as an unprotected department, faces further cuts. With the large flood defence budget now set till 2020, other areas are likely to suffer.

Former Communities and Local Government secretary Eric Pickles was widely loathed by the renewable energy industry for repeatedly overruling planners to turn down onshore wind farms. Greg Clark, by contrast, earned a reputation as a calm and thoughtful shadow energy and climate change minister up to 2010 and saw through controversial planning rule changes with huge fuss during the coalition government. Planning decisions relating to fracking and new airports will test Clark. But he may bring a more evidence-based approach to rubbish collections than Pickles.

The promotion of Oliver Letwin to full cabinet member and in charge of Cabinet office is another boost for green businesses and campaigners. Letwin is seen as one of the most environmentally friendly Conservative MPs.

Some Twitter reaction to Rudd’s apppointment

@NickMolho @dpcarrington Agree good choice - innovative moderniser. And has potential to convince Osborne of econ benefits of climate action — Stephen Tindale (@STindale) May 11, 2015

Good news this am! @AmberRuddhr who has done huge amounts of work for #climate, appointed as new #energy secretary http://t.co/e8RnJdHgBg — REA (@REAssociation) May 11, 2015

Congratulations @AmberRuddhr. A minister that understand the business case for low carbon & energy efficiency and some welcome continuity. — John Alker (@johnalker) May 11, 2015