Most public middle and high school science teachers in the United States are devoting two hours or less per course to the topic of climate change —and they are often getting the facts wrong, according to a new study published Thursday in the journal Science.

While three out of four teachers are teaching the issue, only half of those instructors are correctly explaining that humans are driving climate change. An even smaller number of teachers are aware of how overwhelming the scientific consensus on the issue is.

These findings appear in a landmark study that involved a comprehensive national survey of public school science teachers for the first time. It asked if and how they are talking to students about climate change. The results come as at least 16 states are adopting a new science curriculum (the Next Generation Science Standards) that tackles climate change more directly and in greater depth.

The study was conducted by researchers from Penn State University, Wright State University in Ohio and the California-based nonprofit National Center for Science Education. They concluded that teachers aren't getting enough training on climate science—and they are being influenced by the politicization of the subject outside of school.

"The fact that 75 percent of teachers are covering this issue at all shows teachers are interested in the topic and they find it important," lead author Eric Plutzer told InsideClimate News.

"Many of them personally believe the burning of fossil fuels is causing warming, but are not aware that view is shared by climate scientists. That lack of awareness surely contributes to the willingness to [entertain] alternatives and non-scientific views in their classrooms," said Plutzer, a political science professor at Penn State.

Multiple studies have shown an overwhelming percentage of climate scientists—97 percent or more—agree that climate change is being propelled by human activity. The Intergovernmental Panel on Climate Change said in its fifth, and latest, report it is "extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century."

Yet just over half of U.S. adults believe that scientists are in consensus about the human contribution to climate change, according to a 2015 poll by Pew Research Center. Fueling this disconnect are campaigns by fossil fuel interests and their networks of conservative organizations to cast doubt on the science. Politicians are playing a role, too. Nearly all of the leading Republican presidential candidates have questioned the human role in global warming.

For the study, researchers contacted 5,000 teachers in the fall of 2014; about 1,500 responded. The participating teachers came from all 50 states and represented a mix of urban and rural schools of both majority and minority communities. They also included general science teachers at the middle-school level and biology, chemistry, physics and earth science teachers in high school.

However, the surveyors noted that schools with large minority populations were underrepresented in the total response. The researchers tried to compensate for this data gap through their statistical analysis by giving greater weight to answers from teachers in minority communities.

About 70 percent of middle school teachers and nearly 72 percent of high school teachers said they spent 1-2 hours on climate change per course. Of those teachers, just over half (54 percent) correctly taught students that the scientific consensus is that humans are causing global warming.

That leaves 30 percent of teachers who have incorrectly characterized global warming as having mainly natural causes; an additional 15 percent of teachers reported either ignoring the origins of climate change in class or avoiding the topic entirely.

The survey also tested teachers on their knowledge of the extent of the scientific consensus of human-caused global warming. Only 30 percent of middle school teachers and 45 percent of high school teachers selected the right answer.

"To find that some of our science teachers are misinformed on that incredibly important point is a bit distressing," said Edward Maibach, director of the Center for Climate Change Communication at George Mason University, in Fairfax, Va. Research has shown that people who misunderstand or underestimate the scientific consensus "are themselves less certain of the fact that climate change is happening, that it's human caused, that it's potentially harmful, even that it's solvable," Maibach said.

When asked about their personal views on the issue, nearly 70 percent of teachers said they believe humans are causing global warming. That means more said they agree with the science than those who actually taught that view, explained Plutzer.

Researchers discovered the best predictor of a teacher's classroom approach to climate change was political affiliation. Conservative-leaning instructors were more likely to teach that climate change is driven entirely by nature, or a combination of humans and nature.

Besides assessing a teacher's climate science knowledge, opinions and how they taught the issue, the study offers two suggestions for improving the accuracy of classroom instruction: provide more climate science resources to teachers and help teachers navigate the controversy surrounding the issue.