Most Republicans don't believe in climate change

An overwhelming number of scientists say global warming exists, is harmful and is caused by human-created carbon emissions, from cars, factories and other sources. Even climate-change "skeptics" agree that more carbon dioxide in the atmosphere means higher temperatures.

"Ninety-seven percent of top scientists are in agreement, but the public is split about 50-50," University of Minnesota professor John Abraham said.

Meanwhile, a group of hundreds of U.S. scientists announced this month they want to speak out on climate change to battle misinformation.