The world is undergoing unprecedented changes in many of the factors that determine its fundamental properties and their in- ence on society. These changes include climate; the chemical c- position of the atmosphere; the demands of a growing human population for food and ?ber; and the mobility of organisms, ind- trial products, cultural perspectives, and information ?ows. The magnitude and widespread nature of these changes pose serious challenges in managing the ecosystem services on which society depends. Moreover, many of these changes are strongly in?uenced by human activities, so future...

The scientific community has voiced two general concerns about the future of the earth. Climatologists and oceanographers have focused on the changes in our physical environment--changes in the climate, the oceans, and the chemistry of the air we breathe. Environmental biologists, on the other hand, have addressed issues of conservation and the extinction of species. There is increasing evidence that these two broad concerns are intertwined and mutually dependent. Past changes in biodiversity have both responded to and caused changes in Earth's environment. In its discussions of ten key...