Public opinion about climate change was reviewed in the National Science Board's Science and Engineering Indicators (PDF) 2014.
Climate change, according to the NSB's report, has "been the subject of widespread polling in recent years, with evidence showing clear shifts in views" (p. 7-40). A 2012 survey from the Pew Research Center was cited as showing that 67% of Americans accept that the earth is getting warning and about two thirds of them (so 42% of respondents) attribute the cause to "human activity such as burning fossil fuels" while one third (so 19% of respondents) attribute the cause to "natural patterns in the earth's environment. The historical high for the "human activity" answer is 50% in 2006; the historical low is 36% in 2009.
"Many of the other countries surveyed show more concern than the United States about climate change," the NSB's report adds (p. 7-5). According to a 2010 survey from Gallup, asked about the causes of rising temperatures as part of global warming or climate change, 34% of respondents in the United States, 46% of Eastern Europeans, 49% of Western Europeans, 56% of Latin Americans, and 76% of respondents in "developed Asia" said that it was a result of human activities. Only respondents in sub-Saharan Africa (22%), Middle East and North Africa (25%), and "developing Asia" (27%) were less likely to agree than Americans.
A variety of reports and commentaries on previous polls about public opinion about climate science is available on NCSE's website.