The state legislature of Tennessee has given legal cover to public school teachers to challenge the science of evolution and climate change, in a move that looks set to deepen a debate about politicisation of the classroom.

The bill passed in the Tennessee Senate this week provides legal protection to teachers who personally do not believe in evolution or the human causes of climate change, and instead want to teach the "scientific strengths and weaknesses of existing scientific theories".

It comes at a time when science associations are increasingly concerned by moves to inject religious or ideological beliefs into science teaching ahead of the release next month of a new set of education standards which give a central place to climate change.

The new standards, based on recommendations from the National Research Council, are not mandatory for all states. But they have already provoked a backlash from states, such as Utah, which have officially ruled climate change is not settled science. An unauthorised release of documents from the rightwing Heartland Institute last month revealed an ambitious plan in 2012 to discredit existing teaching on climate change.

The Tennessee measure, which passed by 24-8 votes, was strongly criticised by the American Association for the Advancement of Science and the National Centre for Science Education, who called it a step backward. The house approved a similar version of the measure last year.

Bloggers called the move a throwback to the Scopes monkey trial of the 1920s, when a Tennessee public school teacher was convicted and fined for teaching evolution.

Supporters of the measure said it would encourage critical thinking. "The idea behind this bill is that students should be encouraged to challenge current scientific thought and theory," Bo Watson, a Republican state senator and the bill's sponsor, told reporters.

But the National Association of Biology Teachers said the measure, would encourage non-scientific thinking – not critical thought.

"Concepts like evolution and climate change should not be misrepresented as controversial or needing of special evaluation. Instead, they should be presented as scientific explanations for events and processes that are supported by experimentation, logical analysis, and evidence-based revision based on detectable and measurable data," the organisation said.

The bill still has to be signed into law by the state's governor, Bill Haslam, who has said he will discuss it first with the board of education.

Texas and Louisiana have introduced education standards requiring teachers to describe climate change denial as a valid scientific position. A California school board last year instructed teachers to tell students that climate change was controversial, but later reversed the directive.

The National Centre for Science Education launched a project earlier this year to support science teachers coming under pressure from those who dismiss climate change. © Guardian News and Media 2012

[Biology teacher via Shutterstock]