The number of Americans who believe there is solid evidence that the Earth is warming because of pollution is at its lowest point in three years.
That's the conclusion of a national survey released Thursday by the Pew Research Center for the People & the Press.
The poll of 1,500 adults found that only 57 percent believe there is strong scientific evidence that the Earth has gotten warmer. The steepest drop occurred over the last year, as Congress and the Obama administration have taken steps to control heat-trapping emissions for the first time.
Half the respondents still said they supported limits on global warming gases.
The poll's results differ from previous surveys which have shown an overwhelming majority of Americans believe global warming is happening.