Temperature observations during the 20th century reveal a warming trend unlike any other in many millennia. As one of the preeminent scientists looking for an explanation of this phenomena, Princeton University professor V. Ramaswamy provides an overview of existing climate models and explains in an accessible manner how various natural and anthropogenic variables potentially bring about climate change. Through his summary of available research, Ramaswamy argues that human-induced variables, particularly greenhouse gas emissions, appear to be primarily responsible for the warming trend of the 20th century.

The realization that society's reliance on fossil fuels is resulting in alarming changes to the Earth's climate is forcing people to evaluate a host of issues concerning energy consumption and its effect on the environment. This public event addresses these issues and endeavors to educate concerned citizens about the challenges that lie ahead. In the first half, David Keith, an expert on energy and professor at Carnegie Mellon University, describes the world's current consumption of fossil fuels and suggests future options for energy that will reduce greenhouse gas emissions. Keith presents the surprising idea that fossil fuel consumption can continue without its harmful side effects provided energy companies pursue carbon sequestration technologies, which Keith argues are both possible and practical. In the second half, Stanford University professor Steve Schneider talks about the challenging policy dilemmas presented by climate change in both the developed and developing world. As a possible model for pursuing environment-friendly policies, Schneider offers the case of Bhutan, a developing country that has favored environmental and cultural production over the material benefits of Western-style industrialization. This event is part of the Walter Orr Roberts Public Lecture Series. Recorded on July 25, 2000 in Aspen, Colorado.

Following the Earth Summit (aka "Rio") in 1992, the task became to develop agreements on how to curb greenhouse gas emissions across the globe. One of the great challenges was, and still is, to address developing nation such as China that are ever growing emitters of greenhouse gasses. In this video, Dr. Thomas Heller discusses some of the major issues involved with international environmental law and how they relate to China.

Dr. Stephen Schneider believes that in addition to the usual array of baffling scientific uncertainties, cultural, psychological and educational obstacles make these already difficult problems virtually unsolvable so long as we continue to deny their existence. In this lecture, Dr. Schneider, a professor from Stanford University and a public spokesman for global change issues, provides an overview of the science behind global change and discusses public resistance to its evidence. Dr. Schneider argues that in order to have a functioning democracy, citizens must start understanding and grappling with these pressing issues in global change.

Dr. Richard Somerville speaks on how a sustainable future depends on scientific research, a global energy policy, and the political will that humanity applies to deal with the major issues of our times, including the goal of a stable world population.

The field of global change science is a relatively young field, developing out of the recognition of the sizable impact humans are making on the planet. In this lecture, Robert Corell, assistant director of the National Science Foundation, provides an overview of the scope of global change science and touches on its major contributions. In addition, Corell offers some comments about policies that can address global change issues.