A team of Stanford University researchers found some California science textbooks from major publishers portray climate changes as a point of debate instead of scientific fact.

The research team is concerned these misrepresentations are having a negative impact on youth in the United States. 

"We found that through language choices, the text portrayed climate change as uncertain along several lines, such as whether climate change was happening, whether humans were causing it and what the effects will be," said K.C. Busch, a doctoral candidate in science education at Stanford Graduate School of Education.

Recent polls have shown only 54 percent of American teens believe that climate change is occurring, and 43 percent believe it is not a result of human activity. The researchers believe some of these "erroneous beliefs" could be a result of misrepresentations in classroom textbooks.

In their study, the researchers measured how four sixth-grade science textbooks commonly used in California portray the subject of climate change. The textbooks included: "Focus on Earth Science" (Prentice Hall, 2008), "Focus on Earth Science "(Glencoe-McGraw-Hill, 2007), "Focus on Earth Science" (CPO Science, 2007) and "Earth Science" (Holt, Rinehart & Winston, 2007). They found these textbooks taught, "climate change might be happening and that humankind may or may not be causing it." The need for immediate human response to these changes was unclear in the text. These teachings were written differently from the rest of the textbooks, which usually read as encyclopedias and presented only facts.

"This authoritative stance is accomplished through the use of declarative sentences, which read primarily as definitions. However, in the section on climate change, modal verbs like could, might or may appear," Busch said. "In addition, indeterminate quantifiers are added such as not all or some to statements about scientists. This changes the interpretation and introduces uncertainty."

One example of this can be found in the textbook Earth Science, which stated: "Until recently, climatic changes were connected only to natural causes. However, studies indicate that human activities may have an influence on climate change." A passage in Focus on Earth Science" (Prentice Hall) said global warming could have positive effects for farmers, such as allowing them to plant two crops per year instead of one, but also said: "many effects of global warming are likely to be less positive."

The text tended to describe climate scientists as "thinking" and "believing," instead of conducting real works of science such as analyzing and managing. The effects of climate change were generally described as "less positive" as opposed to "negative." The researchers believe these manipulations of language could reduce students' feelings of urgency in fighting climate change. The researchers noted less than 3 percent of climate scientists disagree about the causes of climate change.

"I think the textbook adoption process is one that is social and political. I imagine that textbook publishers have to 'toe the line' in order to both meet the state science standards and have their book be palatable to a wide range of political ideologies," Busch said. "With that said, however, the science in the science textbook should be accurate. There can be societal debate as to what we should do about climate change, but continuing to portray a scientific debate is dishonest."

The findings were published in a recent edition of the journal Environmental Education Research.