According to an RFF survey (Common Resources):
Despite the fact that the nation’s leaders continue to debate the existence of global warming, the American public appears to be nearly united on the topic—and has been for quite some time. According to a survey conducted by RFF, Stanford University, and USA Today, 73 percent of Americans say that the world’s temperature has been going up over the past 100 years (Figure 1). Responses to the same question, asked in previous studies, have been quite consistent over time. For example, in 2010, that number was 74 percent, and in 1997, it was 77 percent.
Another issue under debate is whether humans have been causing Earth to get warmer, or whether warming has been part of a natural cycle. When asked about this in 1997, 81 percent of Americans attributed warming at least partly to human activity. That number was 80 percent in the 2013 survey (Figure 2).
So maybe it is only a (very) vocal minority of the U.S. who embrace their own opinions about science instead of the scientific consensus on climate change.