LiveScience: After an especially cold winter across much of the United States, the American public was slightly less convinced that the planet is heating up, a new survey shows. A majority of Americans, or 63 percent, still believe there is solid evidence that global warming is real, according to the latest poll from the National Surveys on Energy and Environment (NSEE). That number is down, however, from 67 percent who said the same in the fall. "The fairly cold winter and slow arriving spring weather this...