There's an old joke about how many climate change sceptics it takes to change a lightbulb, the punchline being of course that it doesn't take any: more research is needed to see if the thing needs changing. When I was first told this pun I realised I'd also heard the same figure quoted in a parallel joke about religious fundamentalists: none are needed there too, not because more research is needed, but because God will change the bulb for them if only they pray hard enough.
The humour of these 'lightbulb jokes' always functions in the same way - poking fun at the universal difficulty all groups find to effect change. The problem with change in relation to our climate is that, whatever your position, it is in no way a joke. Rather like the fundamentalists, the issues we are dealing with are of such gravity that choosing to ignore the situation is not an option. If you don't form an opinion on Kanye West, so be it; if you don't form an opinion on hell or our climate, one could very possibly be formed for you, and things, in both cases, could get very hot regardless.
I grew up in a very strong religious climate and so debate over religious issues has been a common experience. You might be expecting me to say that, having begun arguing strongly from one side I've ended up arguing strongly from the other, but the truth is more complex. Having begun arguing strongly from one side, I've ended up realising that arguments rarely do anything to actually change people's minds.
This, I believe, is the lesson the climate change debate needs to learn from religion: nobody ever switched their opinion simply through the process of rational debate.
The lesson is relevant because the more I hear from climate sceptics the more I hear them sounding like religious fundamentalists. By that I mean that, behind the façade of appearing to be thoroughly engaged in debating the issues, what they seem really doing is fighting to avoid having to face up to the truth. In other words, it's not so much that sceptics have looked carefully at the evidence and don't believe the climate science, but more that they fear the trauma of what belief would mean.
All of us want to believe that we are fully rational people and that we accept or reject things on the basis of reasoned choice. All of us want to believe that we are reasonable women and men open to changing our minds as and when the evidence comes before us. As I have watched countless friends and associates move from fundamentalist religious belief I've come to understand this is simply not true.
Change is very rarely a continuous incremental movement that occurs in light of new evidence. On the contrary, what tends to happen is that evidence stacks up against our position, but is resisted and resisted until it can't resist any more. Rather than a smooth shift in position as and when new ideas cross our path, instead we tend to experience changes in our minds as a rupture, a trauma, a sea-change or violent storm - an earthquake if you will: a crunching, brutal shift of our mental tectonic plates after a long period of pressure building up.
There is good reason for this. Our inertia stops us from being swept about with every new whim or trend. It is good to hold a position over time. But there comes a point where to do so is not an act of faithfulness to a vision, but an act of blindness to the facts. We end up resisting what is in plain sight in front of us for as long as possible to prevent the trauma of the responsibility of having to change.
There is a moment in the gospels which might prove oddly instructive here. St Paul - or Saul as he was known then - was the sceptic par excellence. Politically powerful and influential, he was the most vehement, most violent opponent of this new-fangled religion, not only speaking out great tirades against it, but seeking to put to death those who gathered in support. Did reason change his mind? Not one bit. Did a moment of blissful enlightenment? Never. What ended up changing the sceptic Saul of Tarsus into the evangelist Paul was no a moment of light but the trauma of darkness. His sight was taken from him. Plunged into inky blackness, he was forced to confront his own inner blindness. This was no gently reasoned U-turn, but a screaming admission of error.
Tragically, despite the recent record-breaking floods, despite the hurricanes and melting ice and searing temperatures in Australia, an even greater climatic trauma is what it might yet take to change those who, despite the evidence and reasoned argument, still remain deeply sceptical about man-made global warming.
It is tragic because this rupturing mode of change leaves us exposed to terrible danger, simply because it means that the action required to respond is delayed. The pressure of evidence builds up and up, but it is only in the huge trauma of a storm that smashes our final defences that we realise we need to act - and by this time our actions are lagging way behind the enormous climate shifts already in effect.
If I have learned any lesson from my long experiences in the religious sphere it is this: reason will play almost no part in shifting opinions on the environment. This is not to say that we mustn't keep presenting the facts urgently. Rather, we must be realistic about the ability of facts to change minds.
What environmentalists need to see is that deep down sceptics probably already know that they are wrong, and that continuing to attack them will, to a point, only build up their resistance. Instead of desperately raining more evidence down on them, we need to reflect on how we might best help manage the rupture they will be facing by admitting their error. Everything from countless conversations with those exiting fundamentalism tells me that that it is fear of this trauma, the haunting by the truth they have kept anxiously suppressed, that stops them making the changes that they know need to be made.
Horribly, hell is what stalks both paths here. For the recovering fundamentalist is can take years to move beyond the guilty load that the threat of hell crushed them with. For the recovering climate sceptic, it will be the knowledge that a hellish future for earth may not be easy to avoid any more. Either way, the stakes are too high for jokes. We must give as little ground to sceptics who would have us do nothing to move on carbon emissions as we give to fundamentalists who would blame progress on gay marriage for our recent floods.
Like Saul, many sceptics are politically powerful and wield great influence. Like the early church, what we need are politicians and leaders with the courage to live out the future as it has been revealed to them. It is time to move on from debate to action, hoping that we are not too late, but also, paradoxically, welcoming the trauma of more violent demonstrations of climate change at the doorsteps of those who continue to resist what deep down they probably already know.