A: Not according to the Energy Saving Trust. Over the 12 days of Christmas, a typical string of tree lights left on for ten hours a day would produce 1.44kg of carbon dioxide, roughly the same as two dishwasher cycles. Not much on its own, but this figure leaps to 32,000 tonnes of carbon dioxide overall in the UK, since it is estimated that 90 per cent of households leave their lights on 24 hours a day; lovely for people on midnight strolls, less good for the planet.

But let’s not overreact. What would Christmas be without the twinkle-twinkle of rainbow lights? Especially for children. Thank goodness, then, for LED decorative lights and their efficient beams, which use a quarter of the energy of normal ones and last longer. www.Lights4fun.com has charming Christmas tree-shaped white LED fairy lights (£15 for 40), pictured right; there’s also an extensive range at christmastimeuk.com. If you’re stuck with a centuries-old reel of lights that you can’t bear to throw away, at least use an automatic timer so that they turn off when there’s no one awake to appreciate them.

Q: I have heard that the best thing you can do for the environment is to stop eating meat. Is this true?

A: There are strong ecological grounds for just eating your greens. Research by the University of Chicago this year showed that giving meat the chop would reduce your carbon emissions by 1.5 tonnes every year, making it a better way of combating global warming than swapping to an eco-friendly car.

Livestock generates greenhouse gases in part because fossil fuels are used to produce and transport food, but also because the animals emit large quantities of methane, the most potent of greenhouse gases. How? By breaking wind. I don’t mean to put you off your Christmas turkey, but flatulent farm animals are responsible for 14 per cent of global methane emissions; a single dairy cow produces roughly 400 litres (88 gallons) of gas a day. Plus, they demand space: an acre of arable crops can feed 20 times as many people as an acre dedicated to cows.

So cows are not very green. Instead, we should be eating more vegetables and getting stuck into nose-to-tail eating, the waste-not, want-not approach pioneered by the chef Fergus Henderson. Chewing on chitterlings might not be everyone’s rump steak, but it does mean less methane per meat meal.

ECO-BLOGWATCH: GREEN TAXES

This week I asked what green taxes you would introduce if you were Chancellor and responsible for the Pre-Budget Report. Most of you said Mr Brown should have gone farther. “What about incentives for businesses to reduce their energy wastage?” writes Tim Rutherford-Johnson. “The computers in my building are so ancient you aren’t allowed to switch them off at night.”

Some of you supported him. “Brown’s move to exempt stamp duty on zero-carbon homes is a smart one. It could generate thousands of pounds in savings and really influence people’s choices,” writes Mairi. “Suggestions for council tax rebates for people who take energy- efficiency measures in their homes also show promise.”

Mark wants a separate green fund, treating green taxes as windfalls rather than income for the Government. He wants tax on disposable batteries; incandescent light bulbs and plastic bags, making people pay £1 a battery, £5 a bulb and 10p a bag. The thought of which will make many of us grateful that we’re not Gordon Brown.

Want a better world? Vote with your wallet

If green is the new religion, then we are ethically consuming our way to Heaven. Green spending has outstripped even our devotion to alcohol and cigarettes, according to the annual survey of ethical consumerism, compiled by the Co-operative Bank. It hit a record high of £29.4 billion last year, compared with £28 billion on booze and fags.

Organic, Fairtrade and local produce have never been more popular. But can we buy our way to eco-virtue? In newspapers and magazines you can hardly move for green-gift guides and updates on how you can support charities while doing the Christmas shopping. Wondering whether to splash out £279 on a pink Sony camera for your sister? Why not, since £5 of it goes to charity.

Then there’s Bono’s American Express Red card that raises money for fighting Aids in Africa. Shop on this card and consumerist sins can be forgiven. Should the measly 1 per cent that it donates to charity every time you pay for something put you off, how about Wedge, a loyalty card with a difference? Launched by the Big Issue founder John Bird, and soon to be rolled out across the country, it gives shoppers discounts at local stores and more than 100 independent businesses. Customers pay £20 for the card, of which half goes to local charities (wedgecard.co.uk).

The best thing about all of this is that it indicates a hearty appetite for change. We are voting for a better world with our wallets, which gives the right message to the Government. The Wedge scheme goes a step farther by trying to alter the way that we shop. “If people shop locally they are less likely to glut out,” says Bird. “Wedge is about shopping judiciously for what you need.” But there is still the

danger that shopping is a convenient way of wriggling out of environmental problems. “Don’t fret about climate change, folks, I’ve bought some Fairtrade fruit” is the sentiment, and, let’s face it, spending an afternoon in Selfridges hunting down organic-cotton labels is significantly more fun than other demonstrations of green credentials; banner-waving at the town hall, anyone? According to Friends of the Earth, everything we buy has an environmental impact. “Richer countries need to consume less if we are going to live within our environmental limits and allow others their fair share of the Earth’s resources,” it says.

So, with seven shopping days before Christmas, this week’s message is not going to make me popular. I’ll whisper it: sometimes shopping ethically is not enough, we need to do something more radical, like not shop. Put down those organic Levi’s, go home and sew a patch on the old pair. Do you hate me now?

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