Al Jazeera: Jim Halfpenny, an ecologist and teacher, didnt know where the snow went. He had taken a group of students to see the ancient snowfields of Wyomings Beartooth Mountains, but the vast white expanses had vanished. My stomach dropped. I couldnt believe it, said Halfpenny. Last year I was inside that snowfield. It was 20 feet thick, and we were walking up tunnel mazes made by meltwater. For the first time in recorded history, the ancient Beartooth snowfields near Yellowstone National Park melted....