Deborah Orr: If George waves his apple core at me, I'm ready with my compost bin

Even I, a fan, have to admit that this sounds a bit on the fatuously judgemental side. Nevertheless, I immediately leapt to the task of installing a composter in my own garden, on the unlikely chance that Mr Monbiot might appear in my kitchen one fine day, and help himself to something from the fruit bowl. It's a long shot, but I am prepared.

I am also pleased with myself, even more so than usual, as I trot, chopping-board in hand to the bin of righteousness, or drift, secateurs poised, round the garden with a trug. People, I tell myself (basing my analysis on the scientific sample of George and me), can change their habits decisively in the pursuit of sustainability. And they can feel good about it too.

Which is a tiny part of the reason why it's such a drag to learn the contents of a new report from the Department for Environment, Food and Rural Affairs. The report highlights the explosion in "food miles", suggesting that the amount of carbon dioxide emitted by food transport increased by 12 per cent in the 10 years from 1992, and continues to rise dramatically.

The report suggests that the cost of food miles to the UK is somewhere in the region of £9bn a year, which is greater than the total contribution of the agricultural sector to GDP and half the total value of the food and drink manufacturing sector. This profligacy, though, horrendously damaging to the environment as it is, cannot even necessarily be challenged by the simple expedient of switching to home-grown produce. Less energy, it turns out, is used to import tomatoes from Spain than to grow them out of season in the UK. Clearly, the act of putting the wee green bit in a box to rot is not quite getting to the heart of the matter.

This is the point at which many people decide that their own little attempts at saving the planet are pitiful drops in the ocean. Why forego the patio heater when the neighbours down the road have two? Why turn the telly off at the plug, if it means that the electric clock on the video flashes every time it's switched back on? Why expend precious cupboard space on green boxes, when the energy used to recycle glass is almost as great as that used to make it from scratch?

There is widespread understanding that environmental change needs to be made on a planetary scale, led by politicians, rather than on a personal scale, led by individuals. Yet, even as we observe in despair the crawling progress that is made on these issues, so we send our various mixed messages, that leave governments - even those not in the blatant grasp of the oil industry - in a cleft stick.

Make Poverty History campaigners are the most touching, because their ideas about free trade and industrial development are so horribly doomed to create the worst environmental damage in just the places they want to help so sincerely.

And those of us with our compost bins and our dishwasher-cleaned glass for recycling in China? Are we the Marie Antoinettes of our age, playing milkmaid as an ugly, self-righteous revolution gathers pace?

The baffling thing about the environment movement is that its inroads into daily habits have been so marginal. My own belief, though, is that if we can fix this, then everything - everything - will fall into place. Surely, whatever contribution that can be made to such a project, however nominal, is valuable.

* No one has been at pains, over the past few days of sad revelation, to point out that the number of innocent victims of the London bombings has diminished by four. Nor, in the avid discussion of the lives and motivations of the bombers, has there been too much inclination to dismiss these mass murderers as "evil" or "monstrous". Perhaps this indicates that there is a broad consensus that these young men were victims too - of ideology, of hatred, of history, of modernity, of fanaticism, and mainly of their own malleable gullibility and lack of self-respect. They wanted, the fools, to be martyrs. Instead, they died as pawns and patsies, idiot victims far more pitiful than those they so blankly annihilated.

Harry Potter and the African witch-doctors

Those of us looking to the Christian faith for insights into the depth of the Islamic schism were disappointed this week. The Church of England, bless it, was still divided over whether living life in an imitation of Christ might have meant following his teachings rather than contriving to be born with a penis.

But even this was not diverting enough. The really bad news was that a new Harry Potter was being published, with Catholic and Protestant united in condemnation.

The Rev Richard Billingshurst triggered the scrapping of a school's Harry Potter day, saying: "The children were being told it was just a bit of fun, but there is an evil reality out there."

Pope Benedict, in what may even be his first appearance in the mainstream consciousness since he was annointed, told a Roman Catholic critic of the JK Rowling children's favourites that the stories "deeply distort Christianity in the soul".

These men ought to get out more. On the bus the other day, I listened to a very loud African woman engage another in conversation. The two of them talked for about two and a half miles about their evangelical London churches, the witch-doctors they'd known in Nigeria and the improving synergy between the Christian Church and African magic in the capital. I was longing to take notes, but too intimidated to do so. My fellow passengers were clearly of the same opinion, since they sat studying the floor without moving a muscle throughout the exchange. When the loud lady got off, she exchanged phone numbers with the quiet one.

I think we ought to know what the Pope and the Reverend think about that lot.

* Absolutely everyone has been saying how butt-clenchingly awful Nigella Lawson is in her new daytime television programme. Rumours suggest, in fact, that the chat show-with-cooking is so bad it's good.

I therefore switched on Nigella yesterday, diligently mining the cultural open-cast in order to save my readers the bother. Dirty jobs, etc...

Sadly, it seems, the moment for Schadenfreude has already passed. In its first minutes it supplied a plethora of reasons why iPods weren't actually that good, why Sudoku wasn't all it was cracked up to be, why the most puzzling thing in the universe is how a jerk like Justin Timberlake got to be Cameron Diaz's boyfriend, and why Frank Sinatra was the over-rated grandfather of the over-ambitious pub-belter. I jotted the recipe down as well.

I can only assume that either the guest - Jayne Middlemass - is such a TV natural that she saved the show on Friday, or that the will for Nigella to fall flat on her beautiful face was very strong indeed. My hunch is that Ms Lawson could yet master the format if she felt inclined to. How odd that we'd all get such a cheap thrill if the opposite was true.