Here is a case study from a United Nation document, Desertification: The Invisible Frontline. “To fight or to flee? These are the stark choices Maria, a single mother from the Bangalala midlands of Tanzania, faces repeatedly. Her choice, along with those of families like hers, is felt all over the world. ‘After the rains failed for a few years, some neighbours claimed our trees were drawing too much water from the ground. We cut them down. Our harvests fell…. That’s when my father and I moved from the midlands to the… river valley…. My mother stayed at Bangalala…. But where we moved to, my crop also failed last year. That is why early this year I moved again, but I left my father behind. I hope to farm here much longer…. But when will this moving end? I cannot afford it anymore.’”