WASHINGTON — Tennessee is poised to adopt a law that would allow public schoolteachers to challenge climate change and evolution in their classrooms without fear of sanction, according to educators and civil libertarians in the state.

Passed by the state Legislature and awaiting Republican Gov. Bill Haslam’s signature, the measure is likely to stoke growing concerns among science teachers around the country that teaching climate science is becoming the same kind of classroom and community flash point as evolution. If it becomes law, Tennessee will become the second state, after Louisiana, to allow the teaching of alternatives to accepted science on climate change.

The Tennessee measure does not require the teaching of alternatives to scientific theories of evolution, climate change, human cloning and “the chemical origins of life.” Instead, the legislation would prevent school administrators from reining in teachers who expound on alternative hypotheses to those topics.

The measure’s primary sponsor, Republican state Sen. Bo Watson, said it was meant to give teachers the clarity and security to discuss alternative ideas to evolution and climate change that students may have picked up at home and want to explore in class.

“There appear to be questions from teachers like, ‘What can we discuss and not discuss that won’t get us in trouble as far as nonconventional, nonscientific ideas, things that student may see videos about on YouTube?’” Watson said. “It doesn’t allow for religious or nonreligious ideology to be introduced.”

The bill’s critics, which include the Tennessee Science Teachers Assn. and the state chapter of the American Civil Liberties Union, counter that teachers currently have no problem addressing unconventional ideas and challenges students bring up. They argue, instead, that the measure gives legal cover to teachers to introduce pseudoscientific ideas to students, and they have asked the governor to veto it.

“Our fear is that there are communities across this state where schools are very small and one teacher is the science department, and they also happen to teach a Sunday school class, and this gives them permission to bring that into the classroom,” said Becky Ashe, president of the state science teachers group. “It’s a floodgate.”

Haslam has until next week to decide whether to sign or veto the measure. If he does not decide within 10 days of the bill arriving on his desk, it automatically becomes law. The governor’s office did not immediately return calls for comment.

Tennessee was the site of the 1925 “Scopes monkey trial,” during which a high school science teacher was tried for violating a state law banning the teaching of evolution. Critics of the new law have called it a “monkey bill,” asserting that it is a throwback to that earlier era of science denial.

Critics’ concerns have been heightened because the education bill originated with the Family Action Council of Tennessee, or FACT, a conservative Christian group based in Franklin. The council’s president, David Fowler, did not respond to requests for comment on the bill. Fowler “did discuss this bill with me and brought the original bill,” Watson said. “The amendment to the bill, which replaces the original bill, was my work, however.”

The council’s original bill and Watson’s amended version differ only slightly.

On its website, the council says the bill is needed because “in many classrooms, Darwinian evolution is currently taught in a completely one-sided manner, with most students never learning anything about growing scientific controversies about the theory.”

Biologists say there is no scientific controversy over evolution, only a political one. FACT’s focus is on evolution, not climate change. The bill’s passage was hailed by the Discovery Institute, a group that seeks to have alternative theories to evolution taught in public schools. The Tennessee bill is based in part on the institute’s model legislation.

neela.banerjee@latimes.com