FUNDAMENTALS

Exploring public opinion about global warming begins by gauging how many Americans believe that the planet has been warming, what people think has been causing warming, and whether people believe it is a threat.  If most people believe that warming has not been happening or is not a threat, then public support for government action to address the issue seems likely to be minimal. Thus, beliefs about existence and degree of threat may be important determinants of policy preferences.

THE EXISTENCE OF WARMING

Since 1997, large majorities of Americans have believed that the Earth has probably been warming. In 1997, 77% of Americans said so. This percentage rose and fell during the ensuing years: rising to 85% in 2006, dipping to 75% in 2009, rising to 83% in 2011, dropping to 69% in 2015, and rising again in 2020 to 81% (see the figure below). These percentages suggest remarkable and consistent agreement among Americans on this question.


Question wording can be found here.

CERTAINTY ABOUT EXISTENCE

In her book, Merchants of Doubt, historian Naomi Oreskes asserted that the fossil fuel industry and its supporters had been engaged in efforts to reduce the certainty with which some Americans believed that global warming has been happening and to increase the certainty with which others believed that it has not been happening (1). Our surveys suggest that since 1997, there has been no systematic shifting of certainty in either of these ways.

Among Americans who have believed that warming probably has been occurring, the proportion expressing this view with high certainty was quite consistent between 1997 and 2015, ranging from 44% to 58% (see the figure below). In 2020, it reached an all-time high of 63%.


Question wording can be found here.

Among people who believed that warming has probably not been happening, the percentage of Americans expressing high certainty between 1997 and 2015 was typically in the low 30s and was 36% in 2018. However, this percentage saw a significant increase in 2020, with 44% of this subset of respondents expressing a high level of certainty.


Question wording can be found here.

People who have believed that warming probably has been happening have been more certain than people who believed warming probably has not been happening. In only one of the years in which this survey was conducted (2009) was certainty higher among people who doubted the existence of warming than among people who believed that warming has been occurring. In every other year, the proportion of individuals expressing high certainty was greater among individuals who believed in the existence of warming than among those who did not.

FUTURE WARMING

Large majorities of Americans have believed that warming will probably occur in the future if nothing is done to prevent it. This percentage ranged from a low of 72% in 2011 and 2012 to a high of 76% in 2013 and 2020, as shown in the figure below by link provided.


Question wording can be found here.

Certainty about future warming has steadily increased since 1997. Among people who said that the Earth’s temperature will probably go up during the next 100 years if nothing is done to prevent it, the proportion who expressed high certainty increased from 45% in 1997 to 68% in 2020 (see the figure below).


Question wording can be found here.

Compared to those who thought the world’s temperature would go up over the next 100 years, respondents who thought it would not go up showed less certainty in this sentiment. The percentage of this group of respondents ranged from a low of 19% in 1998 to a high of 44% in 2010. This percentage was 41% in 2020.


Question wording can be found here.

CAUSE OF GLOBAL WARMING

In 2014, The Intergovernmental Panel on Climate Change (IPCC) asserted that human-caused greenhouse gases emitted during the last century “are extremely likely to have been the dominant cause of the observed warming since the mid-20th century” (2). How many Americans have thought human action is at least partly causing global warming?

Since 1997, large majorities (about 75%) of Americans have held this view, ranging from a low of 70% in 2009 to a high of 83% in 2007. Identical numbers appeared in 2006, 2013, and 2018 (80%). The percentage of respondents who believed this was 82% in 2020.


Question wording can be found here.

WILL WARMING BE GOOD OR BAD?

Our site still helps in one way to explore perceptions of threat is to ask people whether they believe that global warming would be good, bad, or neither good nor bad. Answers to this question suggest that majorities of Americans have perceived warming to be threatening.

Regardless of whether they believed that global warming had been occurring over the past 100 years, a majority of Americans thought that an increase in the world’s temperature, if it had occurred over this time span, would be bad, and this majority has only increased throughout the years. In 2012, only 51% Americans held this belief; however, an all-time high of 67% of Americans believed this in 2020.


Question wording can be found here.

The proportion of Americans who said that warming of five degrees Fahrenheit in the next 75 years would be bad has ranged from a low of 58% in 1998 to a high of 70% in 2008 and 2020 (see the figure below).


Question wording can be found here.

Very large majorities of people have believed that global warming will be a very serious or somewhat serious problem for the United States in the future, dipping from 82% in 2006 to 73% in 2009 and registering 80% in 2020 (see the figure below).


Question wording can be found here.

Even larger majorities of people have believed that global warming will be a very serious or somewhat serious problem for the world, dipping from 85% in 2006 to 76% in 2009 and slightly increasing in the years that followed, as shown in the figure below. 82% of Americans held this view in 2020.


Question wording can be found here.

References

  1. Oreskes, N., & Conway, E. M. (2010). Merchants of doubt: How a handful of scientists obscured the truth on issues from tobacco smoke to global warming. New York: Bloomsbury Press.
  2. Intergovernmental Panel on Climate Change (November 2014). The IPCC’s Fifth Assessment Report (AR5). Retrieved from https://www.ipcc.ch/pdf/press/ipcc_leaflets_2010/ipcc_ar5_leaflet.pdf