Presidential candidate Mitt Romney, in danger of losing his 2012 Republican primary front-runner status, Wednesday tweaked his position on global climate change, saying he does not know if humans are the primary cause. Romney, the former Massachusetts governor, also said he would not place restrictions on carbon emissions if elected and did not favor spending heavily on climate solutions. He was asked about global warming at a town hall meeting in Lebanon, New Hampshire, and said he believed the world is getting hotter and humans contribute in some way to the change. "Do I think the world's getting hotter? Yeah,...