About 13 million people—half of them fewer than 20 years old—inhabit Burkina Faso, a landlocked, tropical west African nation slightly larger than the state of Colorado. Limited natural resources on the savanna include limestone, phosphates, pumice, and salt. Winters are dry, summers hot and wet. Soil degradation, deforestation, recurring droughts, and desertification plague arable land, only 100 square miles of which are irrigated. Ninety percent of working Burkinabe are subsistence farmers.