A record number of Americans are concerned about climate change, a Gallup poll released Wednesday indicated. Far more people than in recent years say they believe global warming is a serious threat, that the effects are happening now and that global warming is caused by human activity.

Nationwide concern over global warming has been rising since it bottomed out in 2011. Gallup suggested the low numbers seen in 2011 could be attributed to attention diverted by the recession. On the flip side, high levels of concern reported in 2007 might have been caused by the May 2006 release of Vice President Al Gore’s climate-change documentary, “An Inconvenient Truth.”

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Gallup also noted the poll was conducted from March 1-5, immediately after the second warmest February on record. The poll was conducted through telephone interviews with 1,018 adults with an error rate of 4 percentage points.

In the recent poll, 45 percent of people said they had “a great deal” of concern about global warming, up from 37 percent a year ago and 25 percent, the smallest portion, in 2011. Sixty-two percent said the effects of global warming had already begun while 42 percent said it posed a “serious threat.” Fifty-seven percent predicted Trump would do a “poor job” of protecting the environment.

Sixty-eight percent of people, the highest percentage Gallup has ever recorded, said human activity was to blame, a sentiment about which Environmental Protection Agency Administrator Scott Pruitt has voiced skepticism. Pruitt caused controversy earlier in March when he said he did not believe carbon dioxide emissions were a main contributor to global warming.

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“No, I think that measuring with precision human activity on the climate is something very challenging to do, and there’s tremendous disagreement about the degree of impact,” Pruitt said when asked if he believed CO2 was a proven “control knob” for climate change. “So no, I would not agree that it’s a primary contributor to the global warming that we see. But, we don’t know that yet, we need to continue the review and analysis.”

The EPA, the organization Pruitt now leads, contends differently.

“It is extremely likely that human activities have been the dominant cause of warming,” the EPA’s website reads.

GettyImages-85176796 Activists hold signs calling for action on climate change in Washington, March 2, 2009. A Gallup poll indicates record numbers of Americans are concerned about global warming. Photo: Getty Images