New York Times: On Route 11 north of Tuscaloosa, Ala., last April, a pickup truck pulled up next to Greta Browne, and a young man began lecturing her about global warming. He had seen Ms. Browne’s T-shirt announcing that she was "Walking for the Climate," and he wanted to set her straight. Humans, he told her, have nothing to do with heating up the planet. Ms. Browne, 65, a Unitarian minister from Bethlehem, Pa., has encountered more than one global warming naysayer since last March, when she …