When I was at school, if you wanted to save the world, you kept quiet about it. Even a passing interest in saving the planet could become a source of ridicule. To this day, my school friends delight in reminding me about an earnest campaign I waged, aged 14, on behalf of elephants whose tusks were being sold illegally. Disastrously, it centred on a deeply unstylish jumper with the word Elefriends on it.

Today, I am happy to report, this is no longer the case. A recent survey by the Future Foundation found that 20 per cent of the teenagers questioned saw themselves as “hardcore greens”. With climate change centre stage and eco-living no longer a fringe issue, it has become acceptable for teenagers to promote green matters both in and out of school.

The three teens I spoke to were inspired by different aspects of the environment, but were all equally dedicated to their role as green messengers. Not only spreading the word among friends, but also taking their views home, explaining to parents and neighbours why we should all be doing our bit to protect the environment. There's even a book, published last year, called How to Turn Your Parents Green (Tangent Books; £6.50). It makes the point that as young people will inherit the world's problems, they are in a unique position to make adults listen. And teenagers make natural campaigners: apart from their passion and energy, I find that eco-nagging is much easier to take from someone half your age.

SUMAYA BEGUM, 14

“My mum and dad are quite good about things,” says Sumaya Begum, from Stepney, East London. “We've always turned off taps and now we try not to have more than two lights on at any one time. They see what's happening on TV but often I have to tell them how bad the situation is.” Her younger siblings have also been whipped into shape: “I told my 10-year-old brother that England might one day be under water. Ever since then, he's been saying: ‘Turn that light off, quick!' My sister's is a bit lazier. She's 7 and if I tell her to turn a light off, she'll do it, but she won't exactly run.”

Sumaya became interested in the environment after watching a video at school which showed the impact that climate change would have on the developing world. “It's innocent people who will die,” she says. “Like people from Bangladesh, where my family are from and where there are floods and cyclones. These are not the people who have caused climate change.”

Last year, Sumaya and other pupils from Mulberry School for Girls, in Whitechapel, East London, created a climate change Bill that they presented to MPs in Parliament. It was part of a trial for Friends of the Earth's Shout About schools project (see box, facing page). The Bill included plans to tax gas-guzzlers and force everyone to use energy saving light bulbs.

Since then Sumaya has been appointed to the school eco-council, made up of eight students and a couple of teachers. It meets once a week to discuss how to make the school more eco-friendly, with the aim being to gain Eco-School status.

“No one teases me about being on the eco-council because it's something to be proud of,” she says. “But some of my friends do think I'm wasting my time. They're like: ‘Why are you so bothered, we can't make a difference. Adults don't listen to us, so there's no point.' I say: ‘We've got to try; it's our life and our future.'”

HOLLY ROWE, 17

“Unless you're really geeky about it, it's OK to be interested in wildlife,” says Holly Rowe, from Audlem, in Cheshire. “You have to be confident and say: ‘Yes, I'm interested in birds', and then people think, OK, fine.”

It was the plight of albatrosses that started her involvement with the RSPB. Amazed that some of her friends didn't even know what an albatross was, she decided to write to the RSPB highlighting the problem of line fishing that kills the birds as they dive to take the bait from the hooks. Shortly afterwards, she was invited to join a team of ten young people who put together Wingbeat, an RSPB magazine written for and by teenagers. She helps to edit and direct the magazine.

“Birds have this really musty image, so Wingbeat tries to incorporate other environmental issues to encourage teenagers to get involved,” says Holly. Although climate change is covered in geography and the sciences, Holly wishes her school, in Newcastle under Lyme, did more on wildlife and the environment.

“We'll have discussions on things like drugs, bullying and alcohol, but it would be good to have one on global warming,” she says. But she recognises that overexposure can also be a problem. “For some people, global warming has been an issue all their lives. It's been covered so much on the TV that people stop taking notice.”

Holly says that more people should appreciate the wildlife in the UK. “I'd like everyone to take time to go somewhere like the Lake District with their family and appreciate what's around them. Even if you live in a city, you can go to a park and look around,” she says. “Caring for the environment shouldn't be about giving something up, like watching TV, but doing positive things, such as putting some food out for the birds.”

MATT McMULLEN, 17

When eight new TVs were installed as electronic noticeboards around Matt McMullen's school at Chipping Campden, in the Cotswolds, he decided it was a step backwards in the battle against climate change. So he stuck up posters around the school with pictures of power stations chugging out smoke. He says: “I thought, ‘How could massive LCD TVs around the place be a good thing?'”

But his stunt backfired. He was marched off to see the technology teacher, to learn that this was, in fact, a step towards a paperless society and that the TVs were energy-efficient. “I found out that one of these low-energy TVs uses less electricity in a day than it takes to boil your kettle,” he says.

As well as prompting the creation of the school's Sustainability Committee, of which Matt is a founding member, this was also the start of his active role in other green affairs. The committee is planning green measures, from Hippo water-saving devices in the toilets to recycling boxes in every classroom. Matt has also set up a school branch of the environmental group People & Planet, through its sixth-form network, and has organised several fair trade days.

“I became interested in fair trade after learning about economic injustice and the limited rights that workers have in other parts of the world,” he says. “In a couple of months, we're getting a Fairtrade vending machine in the sixth-form common room, which will sell certified hot drinks.”

After finishing school, Matt plans to take a year off before university to work as a volunteer for the Fairtrade office in Stratford-upon- Avon, which is a fair trade town. He'd like his school to gain similar status, but worries that people are too conservative to get involved.

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