Diversity describes the reaction to the very current issue of global warming, although most scientists and policymakers agree that there is a real threat to the world. Their message is an urgent, “We have to act now,” not 10 years from now when we are more certain that changes in climate result from human activity.

The National Academy of Sciences, Smithsonian Institution, American Association for the Advancement of Science, and Sigma Xi held the 2-day Forum on Global Change and Our Common Future, May 2 and 3 in Washington, D.C. It was a public meeting, with the aim of presenting the science of global change, its impact on society, and implications for public policy.