Story Highlights Partisan gaps across global-warming measures slightly wider than in 2017

Democrats view global warming seriously; Republicans view it skeptically

69% of Republicans, 4% Democrats say global warming is exaggerated

This story is part of a special series on Americans' views of the environment, global warming and energy.

WASHINGTON, D.C. -- Americans' concerns about global warming are not much different from the record-high levels they were at a year ago. However, the views of some partisans have shifted, creating larger gaps than what Gallup saw last year across all questions about global warming.

Partisan Divisions in Americans' Views of Global Warming 2017 2018 % % Think the seriousness of global warming is generally exaggerated Republican 66 69 Independent 32 34 Democrat 10 4 Say most scientists believe global warming is occurring Republican 53 42 Independent 71 65 Democrat 86 86 Believe effects of global warming have already begun Republican 41 34 Independent 67 60 Democrat 73 82 Believe global warming is caused by human activities Republican 40 35 Independent 70 62 Democrat 87 89 Worry a great deal/fair amount about global warming Republican 36 33 Independent 67 62 Democrat 90 91 Think global warming will pose a serious threat in their lifetime Republican 14 18 Independent 45 45 Democrat 58 67 GALLUP

Gallup's annual survey about the environment, conducted March 1-8, found that Americans' opinions about global warming, like many other issues, have increasingly become politically polarized.

President Donald Trump, who has called global warming a "hoax," may have contributed to this widening divide by reversing a number of government actions to address the issue. These included the announcement that the U.S. will withdraw from the 2015 Paris climate accord, the removal of climate change from the list of top U.S. national security threats and the elimination of the terms "global warming" and "climate change" from U.S. government websites and lexicons.

In general, Democrats view global warming seriously, while Republicans view it skeptically:

Ninety-one percent of Democrats and 33% of Republicans say they worry a great deal or fair amount about global warming, but 67% of Republicans worry only a little or not at all.

While 82% of Democrats think global warming has already begun to happen, only 34% of Republicans agree. Rather, 57% of Republicans think it will not happen in their lifetime (25%) or will "never happen" (32%).

About seven in 10 Republicans (69%) think the seriousness of global warming is exaggerated in the news, 15% think it is generally correct and 15% say it is generally underestimated. Democrats, however, are much more likely to think the seriousness of global warming is underestimated (64%) or correct (32%), and just 4% say it is exaggerated.

Eighty-six percent of Democrats versus 42% of Republicans think most scientists believe global warming is occurring. The percentage of Republicans who say most scientists believe this is down 11 percentage points since last year.

Almost nine in 10 Democrats say increases in the Earth's temperature over the last century are due to human activities more than natural changes in the environment. Just 35% of Republicans agree, while 63% attribute the temperature increases to natural environmental causes.

Four in five Republicans do not think global warming will pose a serious threat to them in their lifetime; two-thirds of Democrats think it will.

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Broad Agreement Among Americans on Some Aspects of Global Warming

Majorities of Americans overall say most scientists think global warming is occurring (66%), it is caused by human activities (64%) and its effects have begun (60%). Yet, the net effect of increased political polarization over the past year is that opinions on each of these measures have edged down slightly.

At the same time, the 45% who think global warming will pose a serious threat in their lifetime is the highest percentage recorded for this measure since Gallup first asked the question in 1997. This is the only issue that saw increased concern among both major party groups.

The 43% of Americans who say they worry a great deal about global warming or climate change is similar to last year's record-high 45% and is still up significantly from 32% in 2015.

Roughly Half of Americans Continue to Take Global Warming Seriously

A Gallup analysis that takes into account four of the global warming questions finds large segments of Americans holding highly consistent views that are either supportive or dismissive of global warming. The remainder have mixed views, generally acknowledging global warming on some questions but expressing doubts or less concern about it on others.

The supportive group, "Concerned Believers," uniformly worries a great deal about global warming and thinks human activity causes it. Seven in 10 Concerned Believers also expect global warming to pose a serious threat in their lifetime. None believes that news reports of global warming exaggerate the problem -- they think reports either underestimate it or are correct.

By contrast, the dismissive group, or "Cool Skeptics," worries little to not at all about global warming. Its members uniformly believe that news reports about global warming exaggerate the problem and doubt global warming will pose a serious threat in their lifetime. They also ascribe warming to natural environmental changes rather than human activities.

The "Mixed Middle" expresses some combination of views across the four items. The slight majority, 53%, thinks news of global warming is correct or even underestimated. At the same time, the majority, 55%, worries only a little or not at all about global warming, and 64% doubt that it will pose a serious threat in their lifetime. The Mixed Middle is split on whether global warming is caused by human activity (48%) or natural changes in the environment (42%).

The size of these groups was stable over the past year, with 48% of U.S. adults categorized as Concerned Believers, similar to 50% in 2017. Nearly one in three remain in the Mixed Middle -- 32% this year vs. 31% a year ago -- while the percentage of Cool Skeptics is unchanged, at 19%.

Democrats More Unified Than Republicans on Global Warming

About eight in 10 Democrats fall into the Concerned Believers camp, while Republicans are less unified: Gallup classifies 45% as Cool Skeptics and 38% as the Mixed Middle. Notably, far more Republicans fall into the Democratic-oriented category of Concerned Believers than Democrats fall into the Republican-leaning Cool Skeptics -- 17% vs. 1%, respectively.

Beyond political party, there are gender, age and educational differences in these global warming categories. Women, younger Americans and college graduates are more likely than their counterparts to be Concerned Believers. These party and demographic differences are generally in line with previous years.

2018 Global Warming Opinion Groups Concerned Believers Mixed Middle Cool Skeptics % % % U.S. adults 48 32 19 Party ID Democrats 81 18 1 Independents 44 38 18 Republicans 17 38 45 Gender Women 54 33 13 Men 42 32 26 Education College graduate 59 23 18 Not college graduate 44 37 20 Age 18 to 34 58 32 11 35 to 54 50 30 20 55 and older 40 35 24 Based on cluster analysis of four Gallup global warming questions: concern about global warming, perception of whether seriousness is exaggerated in the news, whether global warming is caused by human activities and whether it will pose a serious threat in own lifetime Gallup

Bottom Line

The higher level of concern Americans have exhibited about global warming since 2016, particularly in terms of worrying about the issue and believing it is caused by human activity, is largely intact this year.

One reason for this stability is that Americans' views on the issue are becomingly increasingly partisan and therefore entrenched. With Trump reversing many of his predecessors' policies aimed at curbing global warming, Democrats are feeling a greater sense of urgency about the issue, while Republicans have either remained as skeptical as they had been in the past or have become more so.