Environment

That's the claim of oceanographer Dr. Robert Ballard, who says we've explored less than 1% of the deep sea. Ballard has made dozens of dives in manned submersibles, and has been instrumental in the development of research based on robotic, tele-presence. He joins Fresh Air to share some of the discoveries he's made throughout his career.

Lester Brown is the president of the Worldwatch Institute. The organization's latest State of the World report looks into the greenhouse effect, deforestation, and rising sea levels, among other troubling trends. Brown joins Fresh Air to discuss the causes of these phenomena, whether they'll cause permanent changes, and how we can mitigate their effects.

Lopez has a new collection of essays called Crossing Open Ground, which offers what he hopes is a non-judgemental view of environmental change and different interactions with animals and the natural world.

Photographer Robert Adams documents the changing landscapes of the West. He says development in the region is slowly but surely overtaking the natural environment.

Urban planner and designer Lawrence Halprin designs public spaces which take into consideration how people move through a city -- a process he likens to dance choreography.

Sir David Attenborough, host and producer of the new PBS series "The First Eden," which looks at the natural history of the Mediterranean. This follows his award-winning series for PBS "Planet Earth."

Canadian writer and naturalist Farley Mowat. Mowat has written widely on wildlife and the natural habitat, championing the cause of the harp seals, whales, wolves, Eskimos. His books include A Whale for the Killing, The Boat Who Wouldn't Float and Never Cry Wolf. (This is the second part of a two-part interview.)

Ethnomusicologist Steven Feld shares soundscapes of the daily life of indigenous rain forest communities in New Guinea. He explains the importance of song as a mode of communication in the cultures he studied.

Researcher Dian Fossey returns to Fresh Air to share more of her findings about gorillas' social and sexual behavior, and her experience confronting poachers, all of which she details in a new book.

Vukan Vuchic is one of the world's leading experts in urban transportation, and is a professor of Civil and Urban Engineering Transportation at the University of Pennsylvania. He is the author of the book "Public Transportation Systems and Technology," and, in 1982, won the first Dr. Friedrich Lehner Medal, which is awarded to those who have devoted their lives to public transportation.