Michael McCarthy: Cameron is sticking to his green guns despite the risks

It's not quite up there with Princess Diana shaking hands with an HIV sufferer, in 1987, when Aids was still a subject of panic.

But the picture of David Cameron surrounded by huskies as the frozen wastes of the Arctic stretch out behind him qualifies, like that haunting Diana picture, as an iconic image: it unforgettably represents the moment when an attitude changed.

You can call it staged, you can call it a stunt, but there is no doubt that this image marks a wholly new psychological departure, and that it would have occurred to none of Mr Cameron's three failed predecessors as Tory leader, William Hague, Iain Duncan Smith and Michael Howard, to mark a shift in emphasis in Conservative policy by going to northern Norway to tickle a dog.

Embracing the issue of climate change – by visiting the Arctic where it is most visible – was an essential part of the first half of the Cameron project, the second half of which, of course, is to be elected to power. The first half was to become electable, and we are starting to forget that for all of the Hague, Duncan Smith and Howard tenures, from 1997 to 2005, that's what the Tory party wasn't. The Tories were seen by much of the electorate as "the nasty party" – Tory frontbencher Theresa May said so herself. And thus the first half of the Cameron project was to "decontaminate the brand".

Showing that Conservatives cared about the environment was right at the heart of this, and it was very successful. Yet it was noticeable that once brand decontamination had been achieved, Mr Cameron's emphasis on matters green, and on climate change in particular, fell away. After all, though it may make a difference in general attitudes, most politicians consider there are very few votes in the environment, not least in a recession, and the new generation of Tory hopefuls reflect this in their priorities.

Changed priorities, however, do not mean that David Cameron himself has changed his view about the importance of global warming as an issue of policy, as opposed to an issue of politics; and it seems highly unlikely that a Cameron government will renege on the climate change commitments of its Labour predecessor. And that may well mean trouble with a new generation of Tory backbenchers.