For his high school senior project, Zack Kopplin started a campaign to repeal the Louisiana Science Education Act, a 2008 law passed in his home state that opens a “back door” to teaching creationism in public schools, he says. Currently taking a year off from Rice University to work and travel, Mr. Kopplin, 20, is widely recognized as the state’s leading voice against science denial education. He has expanded his campaign to fight similar laws across the country, as well as the use of public vouchers to send students to religious schools. He argues regularly, if unsuccessfully, before the Louisiana Senate to strike down the law, and his April appearance on “Real Time With Bill Maher,” in which he faced off against a conservative economist, Stephen Moore, went viral.

“I’m proud to be from Louisiana, but I don’t want people to laugh at me when I go out of state. ‘Oh that’s the guy from the stupid state with the creationism law,’ ” Mr. Kopplin said.

In Britain in March, Esha Marwaha, a 16-year-old from Hounslow, West London, started an online petition calling for Education Secretary Michael Gove to abandon a plan to remove references to climate change from the geography curriculum for students under 14. The petition got more than 30,000 signatures, and in July, Mr. Gove changed course.

Ms. Marwaha, a self-described geography fanatic, said lessons about climate change — whether it is caused by people or not — are crucial to keeping future students engaged in evidence-based science.