Since telling the public to "vote blue, go green" in 2006 and pledging in opposition to lead "the greenest government ever", David Cameron has had little to say on climate change. In the three and a half years since he entered No. 10, the PM hasn't made a single speech on the subject, nor attended a UN environmental summit. Emboldened by his silence, Tory climate change deniers have rushed to fill the void. Energy minister Michael Fallon has described climate change as "theology" and Environment Secretary Owen Paterson has declared: "People get very emotional about this subject and I think we should just accept that the climate has been changing for centuries." [The 12 warmest years have all come in the last 15.] Tory MPs have put forward a bill to abolish the Department for Energy and Climate Change, and George Osborne has repeatedly posited a false choice between growth and green energy investment.

But confronted by the devastation wrought by Typhoon Haiyan, which some attribute to climate change, Cameron has found his voice again. He told reporters during his trip to Sri Lanka:

"There is no doubt there have been an increasing number of severe weather events in recent years. And I'm not a scientist but it's always seemed to me one of the strongest arguments about climate change is, even if you're only 90 per cent certain or 80 per cent certain or 70 per cent certain, if I said to you there's a 60 per cent chance your house might burn down do you want to take out some insurance? You take out some insurance. I think we should think about climate change like that.

"Scientists are giving us a very certain message. Even if you're less certain than the scientists it makes sense to act both in terms of trying to prevent and mitigate.

"So I'll leave the scientists to speak for themselves about the link between severe weather events and climate change. The evidence seems to me to be growing. As a practical politician I think the sensible thing is to say let's take preventative and mitigating steps given the chances this might be the case."

Admirable words, but will they be supported by policy? At present, the UK's greenhouse gas emissions are rising, not falling, with investment in clean energy at a seven-year low and Britain forecast to miss its carbon reduction targets. Against the advice of the climate change select commitee, Cameron refused to include a 2030 decarbonisation target in the energy bill, despite an estimated saving of £958 to £1,724 for each household and the potential creation of up to 48,000 new jobs.

More recently, in an attempt to counter Labour's proposed energy price freeze, he has pledge to "roll back" green taxes, with no apparent consideration given to the environmental consequences. The energy and climate change commitee warned in response: "Backtracking on these legally binding contracts will damage policy credibility, seriously undermine investor confidence and could increase the cost of capital for new energy investments – thus pushing up energy bills".

But with the PM's green conscience stirring again, is he about to perform another volte-face? As ever with Cameron, one can never be sure what he really believes.