Meanwhile, a previously exotic and uneconomic competing technology emerged. In 1857, inventor Michael Dietz started selling an innovative kerosene lamp. It was clean-burning, reliable and the petroleum fuel didn't spoil on the shelf like whale oil. Plus, because the price of whale oil was driven up, Dietz's lamp had a lower total cost of ownership. By 1859, when oil was discovered in western Pennsylvania, whale oil had lost two-thirds of its market share.

By the 1870s, whalers were begging for government subsidies. Whaling ran out of customers before it ran out of whales.

The whales were saved; not by guilt, fear and good intentions. The whales were saved by profit-maximising capitalists, technological innovators and demanding middle-class consumers who cared more about the light than the fuel that kept it burning.

It's a story that Amory Lovins, co-founder of the Rocky Mountain Institute, likes to recount in his public speeches, and one that is at the heart of a strategy document he co-authored for US big business and the Pentagon called Winning the Oil Endgame, a strategy to get the US and world economy off oil by 2040.

It's a lesson worth pondering. Climate-change activists, as I recounted last week, are reduced to guilt and fear in attempts to persuade us to change our evil ways. Very few will tell the truth: more austerity equals less freedom.

It's unlikely that you or I will vote for people who promise to take away our ability to buy a car we would actually want to drive or use to take our kids shopping. I know this is true because, despite climate scares, over the first 10 days of 2007, more than 22,000 people bought new vehicles in the Republic, a 20% increase on 2006. A higher proportion than ever of those were suburban assault vehicles or, if you prefer, Dalkey Tractors.

So why are the exhortations of the Green Party to shame us and government into tiny cars doomed to fail? For one, I suspect that after centuries of people from London or the Dublin archbishop's house telling them what to do, Irish people are not in a mood to be lectured. For another, any devastating effects of climate change - by which we do not mean the curtailment of Alpine skiing - are likely to be felt first by poor people in faraway places for whom we'd be delighted to hold a charity concert and emote about over a documentary we watch on a plasma screen.

Why don't most people listen to music recorded on lacquer phonographs? Because technologies came along that consumers preferred and, coincidentally, were more widely affordable and made more money for business - albeit sometimes a different business than the old one the new technology disrupts.

So it's likely to be with our current dependence on oil.

If we do change our behaviour, it's unlikely to be down to a sudden desire for austerity or government fiat. The private sector, under pressure to seek greater profits and higher share prices, is the only way to deliver the goods - because it's in their interests.

Hope and greed trump guilt and fear.

One company to watch is Ford, a Detroit dinosaur if there ever was one. Its new CEO is Alan Mulally, who spent 37 years at Boeing, which in recent years has beaten Airbus in part by incorporating ultralight materials into aircraft design.

Planes that carry more passengers for less money. Cars are ridiculously inefficient.

Less than 0.04% of the energy created by the engine is actually used to move the passenger. Seven-eighths never makes it to the wheels and 95% of the rest heats the road and air. The real advances to be made are in retooling for smarter design and more efficient materials and fuels.

That's where the money is.

Because if Ford mass-produced a roomy SUV using carbon-fibre instead of steel, running on advanced biofuels instead of petrol, and actually cost less - you'd probably buy it. And that's more likely to save the planet than you wearing that Greenpeace pin.