A young Mongolian nomad crosses a frozen stream in the early...

ORKHON RIVER VALLEY, UVURKHANGAI, MONGOLIA - 2012/03/19: A young Mongolian nomad crosses a frozen stream in the early spring. Mongolian pastoral herders make up one of the world's largest remaining nomadic cultures. For millennia they have lived on the steppes, grazing their livestock on the lush grasslands. But today, their traditional way of life is at risk on multiple fronts. Alongside a rapidly changing economic landscape, climate change and desertification are also threatening nomadic life, killing both herds and grazing land. Due to severe winters and poor pasture, many thousands of herders have traded in their centuries-old way of life for employment in mining towns and urban areas. (Photo by Taylor Weidman/LightRocket via Getty Images)