According to the latest National Surveys on Energy Environment, a twice-yearly survey conducted by the University of Michigan and Muhlenberg College, "Just 15% of Americans say that there is no solid evidence that the Earth is warming, down from 24% a year ago, and the lowest in the NSEE's history."
Asked "From what you've read and heard. Is there solid evidence that the average temperature on earth has been getting warmer over the past four decades?" 66% of respondents said yes, 15% said no, and 19% volunteered that they were unsure.
Those who said yes were asked "How confident are you that the average temperature on earth is increasing?": 71% of respondents were very confident, 24% were fairly confident, 3% were not too confident, 1% were not confident at all, and 1% volunteered that they were unsure.
Those who said yes were also asked "Is the earth getting warmer because of human activity such as burning fossil fuels, or mostly because of natural patterns in the earth’s environment?": 46% chose human activity, 16% chose natural patterns, 32% volunteered that it was a combination, and 6% volunteered that they were unsure.
Those who said no were asked "How confident are you that the average temperatures on earth are not increasing?": 55% of respondents were very confident, 29% were fairly confident, 11% were not too confident, 3% were not confident at all, and 3% volunteered that they were unsure.
There were 768 adult respondents for the survey, contacted via land line and cell phones between April 5 and April 26, 2016; the margin of error was +/- 4%. The data were weighted by gender, age, race, income, and education.