National Geographic: On the side of a road somewhere in southeastern Australia sits a man in a motionless pickup truck, considering the many ways in which his world has dried up. The two most obvious ways are in plain view. Just beyond his truck, his dairy cattle graze on the roadside grass. The heifers are all healthy, thank God. But there are only 70 of them. Five years ago, he had nearly 500. The heifers are feeding along a public road–"not strictly legal," the man concedes, but what choice does he have? …