Climate change gets the lion's share of media attention, but it is not the most certain, not the least reversible, and not the most significant (to date) of human-caused changes to the earth system. This talk , given by Stanford professor Dr. Peter Vitousek, examines the major components of human effects on Earth, with emphasis on the changing composition of the atmosphere, the transformation of Earth's surface by human activity, and the loss of biological diversity.

Computer models are currently relied upon to provide estimates of possible future changes in the Earth's climate. Results from these models were at the center of the global warming debate at the recent Earth Summit in Brazil. There was a great deal of controversy about whether modeling can yield insights into the planet's future. In this talk, Dr. Warren Washington, researcher at the National Center for Atmospheric Research, comments on the climate research community's views and the skeptical response.

Climate change is a force with global implications as well as unique regional effects. In this lecture, Dr. Norman Rosenberg, manager at the Battelle Pacific Northwest National Lab, explains the evidence for global climate change and then addresses the specific effects of a changing climate on the American Mid-West.