I’ve been a green conservative for as long as I can recall. Perhaps my first ecological feelings welled up as a boy when I saw the copses and fields of my rural Sussex neighbourhood torn up for housing developments. The sense of dislocation I felt at seeing familiar places altered, of trees uprooted, ponds drained and woodlands paved was, I realised later, a conservative impulse.

I liked the world as it was. It was a home of sorts and I was happy in it. And when it was changed by the forces of market capi-talism, forces that seemed utterly indifferent to the human impact of their upheaval, the cultural contradictions of conservatism became much clearer to me.

That was a long time ago and I can appreciate now the parochialism and narrowness of my childhood perspective. But the contradiction - or, perhaps, more accurately the tension - between conservatism and environmentalism endures. You can rebrand the Tory party all you want, but green growth is not an easy concept. In practice, it’s hard and costly and, in a recession, much easier said than done.

In America, there are, alas, some residual and powerful forces on the right that still want to insist climate change is not real. I cannot see how an empirical and sceptical review of the data can lead one to the conclusion that warming is a hallucination. And the good news is that, increasingly, the old conservative debate about whether warming is occurring is being replaced by a much more interesting one about what to do if it is.

Should we bear the heavy economic and social costs of trying to mitigate it in the teeth of a global depression? Or should we find creative ways to adjust to and live with it and hope that the faster growth of a less green world might be the long-term key to developing the new energy resources and technologies to restrain it?

To be perfectly honest, I’m unsure. But a lack of certainty does not seem to me to be a crippling disadvantage in this debate. For one thing, the scientists are themselves unsure precisely how much warming will occur and what its potential effects could be. If you read the very careful and much hedged reports by the Intergovernmental Panel on Climate Change (IPCC), you find that good scientists do not proclaim total disaster with the zeal of Al Gore. They forecast a range of possibilities, with another range of effects, and they freely admit the difficulty of judging which is the likeliest.

Economists, at least the good ones, in turn exercise the same sort of caution. The “cap-and-trade” emissions regulation mantra, which is taken for granted by David Cameron and Barack Obama, can be examined in terms of classic economic costs and benefits. You can do your best to predict how costly it would be to try to prevent climate change by a mandatory capping of carbon emissions and compare this with how costly it would be to do nothing about it - and a whole range of possibilities in between. This is not as exciting or as entertaining as envisioning Manhattan 6ft under water but, in the real world, it’s where adults start to plan the future.

There’s a robust case to be made, if you take this approach, that the economic and social costs of cap-and-trade outweigh the small and rather fragile benefits that restraining climate change would bring. We run the risk of putting a big damper on economic growth (and thereby human well-being), and erecting a complex and often unmanageable regulatory bureaucracy, in order to wring rather minor reductions in global temperature.

Of course, if you believe humans have no right to disrupt the planet’s ecology to this extent and have a moral obligation to leave Earth as we found it, then these arguments are irrelevant.

However, if you see human population growth as it is occurring, and if you accept that billions of Indians and Chinese and Africans will want to improve their lot, and if you think our essential task is to accommodate our own species’ genius and well-being without rendering our planet uninhabitable, you might let your green imagination wander a little. Perhaps a little muddling through might not be so bad. Perhaps new technologies will emerge that would make a massive government attempt to police carbon-emitting industry moot. Perhaps the economic slowdown gives us a breathing space to see if it might happen.

My own tentative view is that, accepting the middle range of options that the IPCC has set out, doing nothing at this point may be the least worst option. And that’s certainly more likely in the US than some may now think. Obama is indeed committed to cap-and-trade in ways that George W Bush never was. However, people forget that Bill Clinton and Al Gore were much more in line with Obama and were stopped from adopting Kyoto by Congress. Congress is still there. And Democrats from the industrial heartland, already reeling from the collapsing auto industry, are in no mood to aggressively land their constituents with another economic burden right now. That’s why, when you look at the congressional schedule, you can see that cap-and-trade is behind healthcare and education in the budgetary process.

The trouble with inaction, of course, is that there is a real risk that warming might unexpectedly accelerate past the middle range of IPCC forecasts. If you look at more recent shifts - and the speed of the Arctic’s disappearance in summer, for starters - the Gore scenario could indeed become likelier. And if that happens, the cost-benefit analysis shifts back in favour of urgent action. Is there a better way to address it?

My own preference is to avoid the bureaucracy of cap-and-trade in favour of a serious carbon and petrol tax that would shift the economic balance towards noncarbon energy. If you gave back the tax revenue through a tax refund, you could avoid depressing growth and help cushion the working poor from higher petrol costs. You need no new bureaucracy to do this – and you’d help drive green decision-making away from top-down government towards more bottom-up human-level calculations.

It’s not as satisfying as a massive government regulatory programme. It tries to counter the worst-case scenarios without assuming them. It hopes that a carbon-hostile tax would prompt a technological breakthrough to solve the problem. And it’s easily reversible if needs be. It’s the kind of green policy that is neither in denial nor in hysteria, and it’s a rough balance between the planet’s needs and humanity’s. Think of it as innovation over regulation - a way to manage the contradictions of conservatism and environmentalism after all.

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