They do not own a car and never have. They have never been on an aeroplane. To get where they need to go they use either bus or train. Very occasionally — if they have a particularly heavy suitcase — they might use a taxi, but no more than once or twice a year.

They do not shop in out-of-town supermarkets or buy fancy fruit out of season. They have never tasted a strawberry in January or a kiwi fruit or mange tout at any time of the year. Most of their vegetables are grown in the back garden or their allotment and the food they have to buy comes from local shops.

They have no need for recycling bins because there is virtually nothing to put in them. Indeed, the very notion of recycling is alien to them. The woman uses a shopping bag, so there are no plastic bags to get rid of and she buys her milk in bottles that are washed and returned. Every scrap of potato peeling or old cabbage leaf ends up in the compost heap and there is no kitchen waste because, quite simply, there is no waste. Stale bread is turned into delicious bread pudding and leftover vegetables into a fry-up.
They buy only what they need because they have no fridge. The larder stays cool enough year round and nothing goes rotten. Ever.

They turn off the light if they are not in the room and if they had central heating they would turn that down too. But they don’t. They have a fire in one room and the rest of the house is as cold as charity.

You may be starting to smell a rat by now and, yes, I am cheating a little. This virtuous couple with an ecological footprint smaller than a dormouse’s paw happens to be my mother and father. It is an accurate picture of how they (and I) lived until I was in my teens. You may very well recognise them if, like me, you were born into a relatively poor working class family 50 or 60 years ago. They were probably your parents too.

Sir Nicholas Stern might well have had them in mind as he worked on his review of climate change and its economic consequences, released by the government last week. The question is not whether we can return to such a simple lifestyle. We won’t and we can’t. The question is what sort of changes we can reasonably be expected to make — and, of course, whether there’s much point in worrying about it anyway, given that this nation produces only 2% of the world’s CO2 emissions.

Even if we shut up shop completely, we are told, the effect would be limited. The Chinese alone are pumping out so much more of the stuff every day, opening a new coal-fired power station every week, that the experts tell us the benefit gained from us all living in caves and eating nothing but nuts and roots would be outweighed faster than you can catch and skin a rabbit for your wife’s new winter outfit.

Two years. That’s all it would take for the Chinese to make up for our spartan lifestyles. And that’s not counting India.

But that misses the point entirely. The debate about climate change is taking an intriguing turn — from practical self interest and arguments about the science to considerations of right and wrong. It’s becoming a moral issue. My parents had no idea they were “green” or that they were leading virtuous lives, but today they would be feted by all right-thinking environmentalists.

Our anger at our American cousins for leading such profligate lifestyles is not based entirely on the damage they are doing to the environment. We get angry at them for their sheer damned selfishness because it makes us feel better about ourselves. There’s nothing like a little righteous indignation to get you out of bed in the morning.

It’s just not right the way they behave — running air-conditioners in their gardens (the latest Californian fad) while we are recycling away like mad, and then jumping into their hot tubs, which are kept bubbling on their balconies in case the neighbours pop round in their 6 litre behemoths for a quick dip. Typical Americans!

Is there, perhaps, the merest hint of hypocrisy here? One of the biggest-selling items in our own garden centres last year was patio heaters — usually collected from the store in a gas-guzzling 4x4. It’s hard to think of a more idiotic and expensive way of hurling C02 into the atmosphere. I sounded off about them on Today a few months ago and you’d have thought I had suggested reinstating the death penalty for double-parking.
One woman told me I was really, really cruel. How else could she escape from the television if she couldn’t sit out on the patio when it was getting a little chilly? I suggested she might buy a nice woolly cardigan (much lower running costs than a patio heater) or even — God forbid — turn off the telly for an hour or so. But my heart wasn’t really in it. I knew she was beyond redemption.()