Fully 88% of voters who support Barack Obama say there is solid evidence that the average temperature on earth has been increasing over the past few decades while just 8% say there is not. And 63% say that the warming is mostly because of human activity.

By contrast, just 42% of Mitt Romney supporters say there is solid evidence of warming while as many (49%) say there is not. Just 18% of Romney supporters think the earth is warming mostly because of human activity.

Obama supporters also are far more likely than Romney supporters to say global warming is a very serious problem (59% vs. 13%). Fully 58% of Romney supports say it is not too serious or not a problem.

Looking at the public as a whole, the percentage of Americans saying there is solid evidence of global warming has steadily increased over the past few years. Currently, 67% say there is solid evidence that the earth’s average temperature has been getting warmer over the past few decades, up four points since last year and 10 points since 2009.

Similarly, an increasing proportion say that the rise in the earth’s temperature has mostly been caused by human activity. Currently, 42% say the warming is mostly caused by human activity, such as burning fossil fuels, while 19% say it is mostly caused by natural patterns in the earth’s environment. Last year, 38% mostly attributed global warming to human activity and in 2010 34% did so. Read More

Russell Heimlich  is a former web developer at Pew Research Center.