PRINCETON, NJ -- Americans continue to express less concern about global warming than they have in the past, with 51% saying they worry a great deal or fair amount about the problem -- although attitudes appear to have stabilized compared with last year. That current level of worry compares with 66% just three years ago, and is only one percentage point higher than the low Gallup measured in 1997.
These results are based on Gallup's annual Environment poll, conducted March 3-6. Each year, the poll asks several questions designed to measure Americans' concern, knowledge, and opinions about global warming.
While Americans' self-professed understanding of global warming has increased over time -- from 69% saying they understand the issue "very well" or "fairly well" in 2001, to 74% in 2006 and 80% in the current poll -- their concern about global warming across several measures is generally in the lower range of what Gallup has found historically.
For example, 49% currently believe the effects of global warming have already begun to happen, similar to last year's estimate and one point above the historical low from 1997. Just three years ago, 61% thought the effects were already occurring. Over the same time, the percentage doubting global warming's effects will ever happen has increased, from 11% to nearly 20%, including 18% this year.
More Than 4 in 10 Say Seriousness of Global Warming Is Exaggerated
The plurality of Americans continue to believe the seriousness of global warming is generally exaggerated in the news (43%) rather than generally correct (26%) or generally underestimated (29%). This is the third year in a row that a substantial plurality has believed global warming's effects are not as bad as they are portrayed, a departure from prior years, when Americans were about evenly split between the three points of view. The percentage who think global warming's effects are exaggerated is down a bit from last year.
Americans Still Believe Pollution Major Cause of Temperature Increases
There is less public consensus today than in the past about the major cause of the rise in the Earth's temperature, but the majority still blames pollution from human activities (52%) rather than natural changes in the environment (43%).
Last year's update marked the closest division of opinion on this issue over the six times Gallup has asked about it. Three years ago, Americans believed pollution to be the primary cause by a 20-point margin.
Global Warming Opinions Highly Politicized
Though changes in the Earth's temperature and its effects on people and the environment are a prime topic for scientists to discuss, the theory of global warming is a hotly debated topic in the political world as well. Democratic political leaders are generally more sympathetic to the idea of global warming and more amenable to policies designed to counteract its effects than are Republican leaders. This division of opinion is apparent among rank-and-file partisans as well.
On each of four key indicators of global warming concern, Republicans and Democrats differ by 30 points or more. The greatest difference is in the view that the seriousness of global warming is exaggerated in the news.
The size of these partisan gaps has grown greater over time.
Americans are clearly less concerned about global warming and its effects than they were a few years ago. While concerns across various Gallup measures did not continue to trend downward this year, they generally held stable near historical lows.
The reasons for the decline in concern are not obvious, though the economic downturn could be a factor. Gallup has shown that environmental concerns tend to take a back seat to economic matters when the economy is in poor shape.
Another possibility is that Americans worry less about environmental concerns under Democratic presidents, who are generally rated higher on environmental protection than Republican presidents.
Additionally, there have been controversies about the integrity of the data and analysis offered by global warming proponents in support of their positions.
The Gallup data do suggest that greater awareness and understanding of the global warming issue do not necessarily result in greater concern about it. The two moved upward in the mid- to late 2000s, but in recent years, concern has fallen as Americans' self-professed understanding has held steady or increased.
Results for this Gallup poll are based on telephone interviews conducted March 3-6, 2011, with a random sample of 1,021 adults, aged 18 and older, living in the continental U.S., selected using random-digit-dial sampling.
For results based on the total sample of national adults, one can say with 95% confidence that the maximum margin of sampling error is ±4 percentage points.
Interviews are conducted with respondents on landline telephones (for respondents with a landline telephone) and cellular phones (for respondents who are cell phone-only). Each sample includes a minimum quota of 150 cell phone-only respondents and 850 landline respondents, with additional minimum quotas among landline respondents for gender within region. Landline respondents are chosen at random within each household on the basis of which member had the most recent birthday.
Samples are weighted by gender, age, race, education, region, and phone lines. Demographic weighting targets are based on the March 2010 Current Population Survey figures for the aged 18 and older non-institutionalized population living in continental U.S. telephone households. All reported margins of sampling error include the computed design effects for weighting and sample design.
In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.
For more details on Gallup's polling methodology, visit www.gallup.com.