No one today can afford to ignore the impact of the human species on its environment. In this topical volume, distinguished international authors identify and analyze areas of rapid and serious change, and outline approaches to some of the outstanding fundamental questions concerning the environment. The opening chapter places the present environmental crisis in a chronological perspective, exploring the changing impact of human populations on the environment since prehistoric times, with particular reference to forest cover, soil erosion and animal extinctions. The contributors then focus in...