Prior to taking Mr. Visco's high school science class, Keith Hogan did not believe humans had had any hand in climate change.
"I thought the media had just picked that up and blown it out of proportion," he said.
Hogan remembers the day the "lightbulb went off," about four years ago. He'd always been into cars and would get defensive if someone tried to pin climate change on vehicle emissions. But when Mr. Visco pointed out that the methane spewing from livestock was actually a more potent greenhouse gas than carbon dioxide, Hogan opened up and began to reconsider, and then accept, the scientific consensus on anthropogenic climate change.
"Keith was like George Bush in disguise," recalled Chris Visco, who is now retired. "It's funny how things progressed with him."
Imparting the science of climate change is not always so easy. Many of Hogan's conservative classmates at Sachem High School in Long Island, N.Y. avoided taking Mr. Visco's class, aware that they'd hear views that conflicted with their own. And around the country -- from Washington State to Oklahoma -- pressure and pushback from skeptical students, teachers and administrators pose challenges.
In 2008, Louisiana voted to allow public school teachers to teach both creationism and the views of climate change skeptics. Last May, a school board in Las Alamitos, Calif., voted unanimously to require environmental science teachers cover "multiple perspectives" on climate change. That decision was later rescinded.
"For every [conflict] you hear about there are probably 10 you don't, and probably 100 teachers that will just not teach it because that is the easiest way out," said Mike Town, an environmental science teacher at Redmond High School in Washington and a participant in a National Academy of Sciences workshop on climate change education.
The National Center for Science Education, long-touted for its efforts to help teachers address evolution in the classroom, has recognized the predicament and announced this week that it would add climate change to its repertoire, offering teachers a range of tools and legal support.
"It's a bit daunting to tell you the truth," said Eugenie Scott, executive director of the NCSE. "It's not like we were bored. There's still plenty to do in the evolution realm."
THE FACTS: NOT ENOUGH
About a quarter of teachers recently polled by the National Science Teachers Association (NSTA) reported facing skepticism about climate change and climate change education from their administrators; more than half faced the same from parents. Further, 82 percent noted that they had dealt with skepticism from their students.
This pressure can have consequences, warns other data. Despite the estimated 89 percent of teachers who believe climate change is happening, a survey by the National Earth Sciences Teachers Association also found that 36 percent had been influenced to teach "both sides" of the debate.
A case in point: After Al Gore's "An Inconvenient Truth" was shown in a Portola Valley, Calif., middle school class, a parent requested that the teacher hold a debate between a climate change-denier and a climate scientist to provide "balance." John Davenport, the union representative who spoke for the teacher in the controversy, consulted with the NCSE.
"They made it clear that this was virgin ground for them," Davenport said, adding that the center told the district that the policy issue belonged in a social studies class, not a science class.
Overall, 63 percent of the U.S. general public agrees that global warming is happening and 35 percent attribute it to natural changes, according to a new Yale report which found similar rates for teenagers' knowledge of the subject.
Most politicians, meanwhile, lack a science background. "We need an informed citizenry to help the politicians make the best decisions," said Scott. "In the case of climate change, the reality is there and the consequences for society are profound."
Anthony Leiserowitz, director of the Yale Project on Climate Change Communication and lead researcher of the report, added that an understanding of climate change is "necessary but not sufficient" for making such decisions. Facts also need to be interpreted through the lenses of values.
He calls climate change the "policy problem from hell," partly because of the long lag time between actions and results on the issue.
Religious and political beliefs also come into play.
Last Friday, in a conversation with Arianna Huffington, public television icon Bill Moyers highlighted other recent findings: "Even if you, a modern American, are presented with a fact you know to be false, you nonetheless reject it if it offends or undermines your belief system," he said.
In his new book, "Fool Me Twice: Fighting the Assault on Science in America," Shawn Lawrence Otto suggests that the same conflict between science and beliefs has played out through much of history. He quotes a letter that Albert Einstein wrote to a friend. "This world is a strange madhouse," Einstein said. "Currently every coachman and every waiter is debating whether relativity theory is correct. Belief in this matter depends on political party affiliation."
Town suggests little has changed today. "If you come from a Republican household and your parents are watching Fox News and trying to pick a candidate, and your science teacher is telling you that climate change is one of the most important things that could impact your life," added Town, "then it's easy to have to find a way to discredit" the latter.
THE NEXT EVOLUTION
Visco first taught climate change in 1977, at a Catholic high school. Since then, he said he's noticed public perception of the topic go from "nothing to awareness to negativity."
That last turning point, Visco said, came around the release of "An Inconvenient Truth." He said the film brought climate change into the public's consciousness, but it also sparked a build-up of denialist propaganda, which then flooded teachers' mailboxes and students' minds.
"In many ways, climate change is where evolution education was about 20 yeas ago," said Scott, noting NCSE's constant struggle with anti-evolution propaganda.
There are many parallels between the two battles, as well as some important differences.
"In the case of evolution, the objection to teaching it is based in religious ideology," said Scott. "In climate change, the objection is based in political and economic ideology."
While both cases are unscientific, only the former has the backing of the First Amendment: "Climate change is going to be a much harder battle to fight," Scott said.
Another key difference is that evolution fits into a core high school course: biology. Climate change, on the other hand, may only come up in an elective course or during middle school -- before most kids have the background to comprehend the complex concepts.
A revision to the science education standards is currently underway, in which climate change will be "explicitly noted," said Francis Eberle, executive director of the NSTA.
Mark McCaffrey, the new programs and policy director for climate change at the NCSE, also emphasized that it was important for the subject to be taught in a "relevant" and "practical" manner.
During his time with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado at Boulder, McCaffrey helped spearhead the Climate Literacy and Energy Awareness Network, which offers resources for teachers to connect the dots between climate and energy consumption.
For Visco's class, that meant teaching his students that small changes could have a large impact on the planet. "I had lots of students who would come in and say, 'My parents hate you. I'm driving them nuts, making them recycle and turn heat down and change lightbulbs,'" he recalled.
In many cases, by teaching his students he was also teaching their parents, something that Yale's Leiserowitz has also found. "Do parents influence kids, or do kids influence parents? Evidence suggests that it works both ways."
"I definitely saw changes in my students, and I definitely saw parents that softened," said Visco.