Rassmussen: Just Third of Americans Believe Global Warming is Man Made

Don Quixote Obama still fighting those windmills regardless of public opinion...

Questions continue to mount over the science behind years of studies that say humans are chiefly to blame for global warming. But reflecting a trend that has been going on for more than a year, just 35% of U.S. voters now believe global warming is caused primarily by human activity.

The latest Rasmussen Reports national telephone survey finds that 47% think long-term planetary trends are mostly to blame, down three points from the previous survey in January. Eight percent say there is some other reason, and 10% aren't sure.

But 56% say President Obama still believes that human activity is the main cause of global warming. That's the highest finding on that question since last March.The president went to a United Nations summit in Copenhagen in December in hopes of reaching an international agreement that would limit human activities that some scientists say contribute to global warming.