Even during the COVID-19 pandemic, as many Americans as ever think that global warming is happening, and as many Americans as ever think that, if it is happening, it is mostly owing to human activity, but only about one in five know that nearly all climate scientists agree that global warming is happening as a result of human activity. Those were among the key findings of Climate Change in the American Mind: April 2020 (PDF).
Presented with a definition of global warming as "the idea that the world's average temperature has been increasing over the past 150 years, may be increasing more in the future, and that the world's climate may change as a result" and asked whether they thought that global warming is happening, a record-tying 73% of respondents said yes, 10% said no, and 16% indicated that they didn't know.
Asked about the cause of global warming, on the assumption that it is indeed happening, a record-tying 62% of respondents said that it is caused mostly by human activities, 29% said that it is caused mostly by natural changes in the environment, 5% opted for "neither because global warming isn't happening," and 5% volunteered that it was a mix of human activities and natural causes.
Asked to indicate "what percentage of climate scientists think that human-caused global warming is happening," only 21% selected a value between 91% and 100% — the correct range, as repeated independent studies have demonstrated. Just about as many respondents, 22%, said that they didn’t know. In all, about six in ten respondents selected a value between 51% and 100%.
The study was conducted by the Yale Project on Climate Change Communication and the George Mason University Center for Climate Change Communication. The questionnaires were self-administered in a web-based environment from April 7 to April 17, 2020, using an on-line research panel of 1029 American adults. The margin of sampling error was plus or minus 3% at the 95% confidence level.