The majority of Americans have limited understanding of the planet’s climate system and the causes and threats of climate change, according to a new study by Yale University. Only 1 in 10 of those surveyed by the Yale Project on Climate Change Communication said they are “very well informed” about climate change issues. And while 63 percent believe that global warming is occurring, many do not understand why. According to the survey, 57 percent of respondents know that the greenhouse effect refers to heat-trapping gases in the atmosphere; 45 percent understand that carbon dioxide traps heat from the planet’s surface; and only 25 percent are aware of coral bleaching or ocean acidification. And the majority of respondents had significant misconceptions about climate science, including the incorrect belief that the hole in the ozone layer, toxic waste, aerosol spray, and acid rain cause global warming. Based on these results, the authors say only 8 percent of respondents would have knowledge equivalent to a grade of an A or B, and more than 52 percent would receive an F grade.