Another summer as hot as this one and Al Gore will become the next president of the United States. Yes, of course, one broiled July and sautéed August do not a global warming make. But it does concentrate the mind wonderfully on the claims that a hotter climate is already here, that it is closely related to fast-rising carbon dioxide levels and that this should not be a political but an empirical question.

The debate, of course, is not completely clear-cut and there have been legitimate arguments about whether what we are observing is due to man-made causes, solar activity, carbon emissions or natural cycles. There have been cogent arguments by Bjorn Lomborg, among others, that it would make more sense to invest in immediately tractable environmental issues such as clean drinking water in developing countries.

But there comes a point at which the data reaches a tipping point of credibility for even the most querulous sceptic. For me, that tipping point is the unexpected recent acceleration of global warming and the now-famous feedback loop in which warming can not just increase gradually, but swiftly — as carbon melts the polar ice-packs, decreases the amount of energy reflected back into space and so ratchets the cycle of warming much more dramatically.

The record heatwaves of the past decade are not flukes. Neither are the more extreme hurricanes and typhoons that we have been experiencing lately. The possibility that global warming will not be a smooth and gradual process, reversible at any point, but an unpredictable and volatile jolt upward renders previous, less alarmist cost-benefit analyses more and more beside the point.

Yes, I saw Gore’s persuasive movie, An Inconvenient Truth. But no, I’m not some sudden convert to environmentalism. Twenty-one years ago I worked at Margaret Thatcher’s then-favourite think tank, the Centre for Policy Studies, and wrote a policy paper called Greening the Tories. It struck me then, as it has dawned on David Cameron two decades later, that the environment is not an inherently left-wing topic. It is, in many ways, a quintessentially conservative issue.

At the core of conservatism, after all, is the word “conserve”. The earth is something none of us can own or control. It is something far older than our limited minds can even imagine. Our task is therefore a modest one: of stewardship, the quintessential conservative occupation.

Conservatives do not seek to remake the world anew. We do not hope to impose upon it some abstract ideological “truth” or bring about some new age for humanity. We seek as conservatives merely to live up to our generational responsibility and to care for the inheritance we have in turn been given. This ecological vision is a Burkean one, which is why Toryism’s natural colour is as much green as blue.

Of all those likely to be alarmed by freakishly hot summers, potentially freezing futures and drastic events such as super-hurricanes, conservatives should surely be the most prominent. Conservatives tend to like things as they are and have been. They are discombobulated by change, which they always experience as, in some measure, loss.

And loss it is. When an old tree is uprooted by a storm, when an old church is razed or an old factory turned into loft apartment, we all sense that something has been lost — if not the actual thing then the attachments that people, past and present, have forged with it, the web of emotion and loyalty and fondness that makes a person’s and a neighbourhood’s life a coherent story.

Human beings live by narrative. We become sad when a familiar character disappears from a soap opera, or an acquaintance moves, or an institution becomes unrecognisable from what it once was. These little griefs are what build a conservative temperament. They interrupt our story, and our story is what makes sense of our lives. So we resist the interruption, and when we resist it we are conservatives.

Resisting massive climate change is resisting a huge disruption of what we have been and there are few endeavours more conservative than that. The sadness one feels at the destruction of, say, New Orleans, is a conservative emotion. There is also something about British patriotism that stirs most deeply when it is reminded of the physical beauty and fragility of the islands that generations have called home.

In the past, the conservative argument against environmentalism was that it was anti-entrepreneurial, that it inhibits economic growth, that it is synonymous with crude attempts by government to control industry. And there are indeed transactional costs for environmental improvements. Some companies went under because of restrictions on the emissions that gave us the hole in the ozone layer. But others thrived; and as long as government policy rests primarily on incentives for market innovation, rather than clumsy efforts to police pollution, disruption can be minimised.

We knew this 20 years ago, as my little pamphlet argued. Instead of crude limits on certain emissions, governments can create markets in pollution permits, allowing companies to buy and sell rights to pollute and so allow economic costs to be minimised. Or the government can tax petrol so the global market makes it more profitable for the private sector to develop new energy technologies more quickly.

In America, car emissions standards are beneath China’s. That is a scandal. Petrol, in real terms, is cheaper in the United States than in the past; and yet the Bush administration still will not touch the tax on it. Mercifully, the states are leaving Washington behind — witness the unlikely alliance last week between Arnold Schwarzenegger and Tony Blair. And if the polls are correct, Congress may be in Democratic hands before too long. As Churchill once remarked, Americans always do the right thing . . . eventually. The question this time is whether “eventually” will be too late to avoid some of the more drastic environmental consequences of more inertia.

There is to my mind one central decision that Washington has to take: to tax petrol to a level that jolts the private sector into serious non-carbon-based energy investment. This is not an impossibility, as some assume. Many on the religious right — dedicated to what they see as moral stewardship of God’s creation — are joining hands with liberal activists to support such a move.

The dreaded neocons are also potential recruits. Weaning the West off oil which is increasingly controlled by Islamist terror regimes is a geo-strategic necessity. If you need a selling point, why not call an increase in petrol taxes a “war tax”? Maybe if Gore had been president in September 2001 we would already be seeing the benefits of such a posture.

What, after all, are the costs of action? Yes, the economy may take a hit from an increase in petrol prices. But the US economy has powered through a sharp increase in energy costs these past few years. If it can survive an increase that is largely financing Islamist terror, why could it not weather an increase that could innovate non-carbon energy resources?

Yes, China and India will be the biggest threats to the atmosphere in the next century. But if the West innovates new energy sources, China and India will adopt them — and buy them from us. That was the core of the call by Martin Rees, president of the Royal Society, for emergency investment in non-carbon technology last week. But the public sector need not do this alone. There is money in green technology. Just as the private sector innovated anti-HIV drugs which then helped to save many in developing countries, so new energy sources can soon be adopted elsewhere.

This kind of green politics is not anti-human or impractical. It’s humane and pragmatic. It’s not ideological; it’s empirical and prudent. Far from violating conservatism’s philosophical core, concern for the world that we inherit is the central animating feature of Toryism at its most imaginative and serious.

We need government to unleash the private sector to protect the country and landscape we love, the seasons we remember, the places we call home. If that isn’t an essential conservative calling, what is?