American school children will for the first time receive extensive lessons on climate change following the adoption on Tuesday of new science education guidelines.

However, the final standards were substantially weakened from earlier drafts.

The final guidelines cut by about a third the amount of time devoted to a subject seen as critical to future generations.

They are also less explicit than earlier drafts about the human role as a driver for climate change. "It's buried at best," said Mark McCaffrey, policy director for the National Center for Science Education.

The new science teaching standards will introduce climate change as a core aspect of science education for middle and high school students

in up to 40 states – in many for the first time.

The guidelines were unveiled at a time when climate change has become

a flashpoint for conservative groups, similar to the teaching of evolution in classrooms

The Next Generation Science Standards are not mandatory. But scientists and educational experts in 26 states helped to develop them, and they will for the first time bring a degree of cohesion to the teaching of climate change, said Frank Niepold, co-chair of the climate education group at the US Global Change Research Program,

who was involved in the three-year effort.

"In the current situation the state standards are all over the map.

It's a hodgepodge," he said. "We are still in a situation where across

the country basically in every state students can still graduate from

high school and in some cases go through college without learning the

basics."

The mission of the new standards was to prepare a new generation of

Americans for college and adulthood, said Matt Krehbeil, a consultant

to the process.

"The NGSS aim to prepare students to be better decision makers about

scientific and technical issues and to apply science to their daily

lives," he said in a statement.

However, the standards appeared considerably shorter than draft versions that had circulated in recent months. Unlike earlier drafts, the final standards do not propose teaching climate change until children are in middle school and high school.

Mario Molina, deputy director at the Alliance for Climate Education, said the experts drafting the guidelines had cut 35% from the sections devoted to climate change, in response to public comments. He did not believe it was political, but was response to a need to compress a great deal of material.

However, he said teachers will now need additional materials and clarifications to teach climate change in detail.

Earlier versions had proposed introducing some aspects of climate change as early as kindergarten.

The standards are also much vaguer about the causes of climate change. An earlier version for primary school students had said explicitly that human activity was a driver of climate change. "It's not as explicit in terms of the connection between human activities and climate change," Molina said.

McCaffrey agreed. "They talk about climate just in a very general way," he said. "At the third grade level they are not explicit that they are talking about human activities."

McCaffrey said the lack of clarity could be an opening for teachers to teach their own opinions in place of science, or resort to DVDs and other materials being pushed into classrooms by conservative groups that deny the existence of climate change.

"It opens the door for teaching a phony controversy," he said.

The new guidelines also offered far less time for teaching about the physics involved in the greenhouse effect. Such knowledge was critical to ensuring students understand that greenhouse gases cause climate change, and that such emissions must be cut to prevent the worst effects of climate change.

"We are not seeing the students need to understand the greenhouse effect," he said. "It was in the earlier version a year ago."

A spokesman for the Next Generation Science Standards refused to comment on the new guidelines, and hung up on the phone when asked about climate change.

The new standards were released at a time when conservative groups in America are making a strong push to limit teaching of established climate science or inject fringe ideas on climate change into the curriculum.

Some 18 states have considered "academic freedom acts" that would allow teachers to depart from established science and deny the existence of climate change – including seven this year alone.

In Britain, meanwhile, draft guidelines released last month cut climate change off the curriculum for children under the age of 14.

But it was hoped that the broad support from states and the involvement of so many experts from the National Research Council the National Science Teachers Association, and the American Association for the Advancement of Science, would defuse any political controversy attached to the teaching of climate change.

"Climate change is not a political issue and climate change is not a debate. It is science. It is strongly supported heavily research science, and our hope is that teachers will not see this as a political issue or a political debate," Molina said.

He said the new standards will help guide teachers on teaching climate change. However, it was critical that science organisations offer support and resources to teachers who may not be as familiar with climate change as with other areas of science.

"There are existing materials out there – DVDS and stuff on YouTube and so forth – that are being used in classrooms to perpetuate confusion. A lot of teachers just don't have the background in science themselves. They may be hesitant and confused. That is why professional development is so vital," he said.