Yale Program on Climate Change Communication

2. Global Warming Beliefs

2.1. About seven in ten Americans think global warming is happening.

Americans who think global warming is happening outnumber those who think it is not happening by a ratio of about 7 to 1.

About seven in ten Americans (73%) think global warming is happening. By contrast, only one in ten Americans (10%) think global warming is not happening. Over the last five years (since our March 2015 survey), the percentage of Americans who think global warming is happening has increased by 10 percentage points.

2.2. More than half of Americans are “extremely” or “very” sure global warming is happening. Fewer than one in ten are as sure it isn’t happening.

Fifty-four percent of Americans are either “extremely” or “very” sure global warming is happening, the highest level since our surveys began in 2008. Far fewer (6%) are “extremely” or “very” sure global warming is not happening.

Over the last five years (since our March 2015 survey), the percentage of Americans who are sure global warming is happening has increased by 17 percentage points.

2.3. Most Americans underestimate the percentage of U.S. adults who think global warming is happening.

About six in ten Americans (59%) estimate that fewer Americans think global warming is happening than the 73% who actually do think so (see Section 2.1 and the Data Tables in the report PDF, p. 37). An additional 23% say they “don’t know.”

2.4. About six in ten Americans think global warming is mostly human-caused.

The 2018 U.S. National Climate Assessment (written and reviewed by hundreds of climate experts over the course of four years) states: “Greenhouse gas emissions from human activities are the only factors that can account for the observed warming over the last century; there are no credible alternative human or natural explanations supported by the observational evidence” (pp. 39-40).http://nca2018.globalchange.gov

About six in ten Americans (62%) understand that global warming is mostly human-caused, an increase of ten percentage points over the past five years (since March 2015). By contrast, three in ten (29%) think it is due mostly to natural changes in the environment.

2.5. More than half of Americans understand that most scientists think global warming is happening.

A review by John Cook and colleaguesCook, J., Oreskes, N., Doran, P. T., Anderegg, W. R. I., Verheggen, B., Maibach, E. W., Carlton, J. S., Lewandowsky, S., Skuce, A. G., Green, S. A., Nuccitelli, D., Jacobs, P., Richardson, M., Winkler, B., Painting, R., & Rice., K. (2016). Consensus on consensus: A synthesis of consensus estimates on human-caused global warming. Environmental Research Letters 11(4). doi:10.1088/17489326/ 11/4/048002 found that six independent, peer-reviewed studies examining the extent of the scientific consensus about global warming have concluded that between 90% and 100% of climate scientists are convinced that human-caused global warming is happening. The most rigorous of these studies found that 97% of climate scientists are convinced that global warming is happening and human-caused.

More than half of Americans (56%) understand that most scientists think global warming is happening, an increase of 16 percentage points over the past five years (since March 2015). By contrast, about one in four Americans (24%) think there is a lot of disagreement among scientists about whether or not global warming is happening, equaling the lowest level since our surveys began. Very few Americans (3%) believe that most scientists think global warming is not happening (see Data Tables in the report PDF, p. 39).

2.6. About one in five Americans understand that almost all climate scientists (more than 90%) have concluded that human-caused global warming is happening.

Although the majority of Americans now understand that most scientists think global warming is happening, fewer understand just how strong the level of consensus among scientists is. Only about one in five Americans (21%) understand that nearly all climate scientists (more than 90%) are convinced that human-caused global warming is happening. However, that number has increased by 12 percentage points over the last five years (since March 2015; see Data Tables in the report PDF, p. 40).

About one in five Americans (22%) say they “don’t know” what percentage of climate scientists think human-caused global warming is happening.Respondents were asked to estimate the percentage of climate scientists who have concluded that human-caused global warming is happening by moving a slider bar which appeared on the screen of their computer. This slider allowed respondents to move the marker from 0% on the left to 100% on the right, or to any whole number between the two. A “don’t know” response option appeared below the slider bar

Public misunderstanding of the scientific consensus – which has been found in each of our surveys since 2008 – has significant consequences. Other research has identified public understanding of the scientific consensus as an important “gateway belief ” that influences other important beliefs (i.e., that global warming is happening, human-caused, and worrisome) and support for action.For more information, see: van der Linden, S. L., Leiserowitz, A. A., Feinberg, G. D., & Maibach, E. W. (2015). The scientific consensus on climate change as a gateway belief: Experimental evidence. PLoS ONE, 10(2). https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0118489