Yale Program on Climate Change Communication

1. Global Warming Beliefs

1.1. Seven in ten Americans think global warming is happening.

Americans who think global warming is happening outnumber those who think it is not by a 5 to 1 ratio.

Seven in ten Americans (70%) think global warming is happening. By contrast, only about one in seven Americans (14%) think global warming is not happening.

The percentage of Americans who think global warming is happening has remained steady since March 2016.

1.2. Nearly half of Americans are sure global warming is happening. Fewer than one in ten are sure it is not happening.

Forty-nine percent of Americans are either “extremely” or “very” sure global warming is happening. Far fewer – 7% – are “extremely” or “very sure” global warming is not happening.

The percentage who are sure global warming is happening has risen steadily over the past three years and is now at its highest level since November 2008.

1.3. More than half of Americans think global warming is mostly human-caused.

The 2014 U.S. National Climate Assessment (written and reviewed by hundreds of climate experts over the course of four years) states: “The global warming of the past 50 years is primarily due to human activities, predominantly the burning of fossil fuels. Many independent lines of evidence confirm that human activities are affecting climate in unprecedented ways” (p. 15).http://nca2014.globalchange.gov/report

A majority of Americans (58%) understand that global warming is mostly human-caused, matching the highest level since our surveys began in 2008. By contrast, about three in ten (28%) say it is due mostly to natural changes in the environment, the lowest level since our surveys began.

1.4. Only about one in seven Americans understand that almost all climate scientists (more than 90%) have concluded human-caused global warming is happening.

A recent review study by John Cook and colleaguesCook, J., Oreskes, N., Doran, P. T., Anderegg, W. R. I., Verheggen, B., Maibach, E. W., Carlton, J. S., Lewandowski, 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: 10.1088/1748-9326/11/4/048002 found that six, independent, peer-reviewed studies about the extent of the scientific consensus about global warming have reached similar conclusions: between 90% and 100% of climate scientists are convinced that human-caused climate change is happening. The most rigorous of these studies found that 97% of climate scientists are convinced that human-caused climate change is happening.

Only about one in seven Americans (15%) understand that nearly all climate scientists (more than 90%) are convinced that human-caused global warming is happening. The most common response to this question – given by about one in three Americans (34%) – is “don’t know.”Respondents were asked to estimate the percentage of climate scientists who have concluded that human-caused global warming is happening by moving a simulated “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. Additionally, more than half of the American public underestimate the scientific consensus.

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., global warming is happening, human-caused, a serious problem, and solvable) 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). doi: 10.1371/journal.pone.0118489