Once, environmental protesters were dreadlocked and mud-spattered, with names like Swampy. They took up residence in trees or tunnels and claimed the rivers of hell ran with Starbucks coffee.
Now, they are teenage school pupils, asking polite but pointed questions and encouraging their parents to turn off the TV at night.
A small group of British pupils is being sent to the international climate change conference in Copenhagen next week, to report back for children's charity Plan UK.
They have also been granted an interview with Ed Miliband, Energy Secretary, and hope to persuade him of the urgency of global warming.
Leon Ward, 17, from Franklin College in Grimsby, has been campaigning against climate change for three years. He believes teenagers can be effective political lobbyists.
"Adults often don't want to mention things," he said. "They have to live and work with people. Young people can be more critical because once we go home, we don't ever have to see them again."
Fellow delegate Annie Pickering, 15, agrees. "I hope to interview as many people as possible - politicians and protesters," she said. "I want to ask whether, if a solid deal isn't made in Copenhagen, they will feel guilty for not doing enough to help their children, their nieces and nephews. They should feel guilty. I think it's better to set ambitious targets than none at all."
When they return to Britain, the pupil delegates will give workshops in their own and neighbouring schools.
"People think, 'Me turning off a light switch won't make a difference,'" Leon said. "In the same way, they think their vote won't make a difference. People are concerned about their own needs, and don't give a flying monkey's about things going on halfway around the world. Or people are scared, and when they're scared they run away. But that stops them doing anything."
He believes change comes in small steps. "Learning to recycle is like learning to put on your jacket or your socks," he said. "It should be second nature. I'd like to inspire other people to make a difference."
But Annie thinks it is vital to speak to politicians as well.
"Politics is quite a competitive job to be in," said Annie, who attends Maidenhill School in Gloucestershire. "Because the election will be happening soon, so much is about getting votes. But instead of going after votes, they should just do all they can to protect against climate change. It might not be popular, but eventually people will think, 'We didn't like him much at the time, but he's done lots to protect our future.'"