Jim and Robyn Dahlin knew replacing the roof of their home in Greenbrae, Calif., would be expensive. But they hadn't planned to spend an extra $15,000 on solar panels. For that, they have their 8-year-old son, Luke, to thank.

After Luke acted in a school play about global warming, he went on a campaign to get his parents to install the panels. He routinely lectured his dad from the backseat of the minivan about how reducing their energy consumption could help save the planet.

Dahlin says he put Luke off at first, not wanting to "just give in ... . " But after doing more research about the energy savings, he relented. Luke, he says, "is proud that we're trying to do our part."

In households across the country, kids are going after their parents for environmental offenses, from using plastic cups to serving non-grass-fed beef at the dinner table. Many of these kids are getting more explicit messages about becoming eco-warriors at school and from popular books and movies.

This year's global-warming documentary "Arctic Tale," for instance, closes with a child actor telling kids, "If your mom and dad buy a hybrid car, you'll make it easier for polar bears to get around." Kids on field trips to the Garbage Museum in Stratford, Conn., are sent home with instructions to recycle cans, bottles, newspaper and junk mail.

"Kids are putting pressure on their parents, and this is a very good thing," says Laurie David, a producer of the documentary "An Inconvenient Truth."

David is also the co-author of a new children's book, "The Down-to-Earth Guide to Global Warming," which urges kids, among other things, to petition mom and dad for recycled-fiber toilet paper. "I know how powerful my kids are," she says.

For Sherrie Mahnami, some tactics go too far. Last month, the mother from Concord, Calif., took her 4-year-old son, Jacob, to see "Arctic Tale." At bedtime, he asked, "Mom, do you think they'll have ice next year?" Explained Mahnami,, "I thought that was a little much."

In Princeton, N.J., James Verbeyst's energy-saving fixation cost his mother $5,500 — the difference between the Toyota Matrix she was going to buy and the hybrid she finally purchased. With every car she looked at that wasn't a Prius, the 8-year-old protested by announcing the Prius's gas mileage.