All the contributors to this collective work are in agreement over a crucial issue: climate change is not only underway, it is accelerating, and it is clearly stimulated by human activities. It is therefore urgent to understand the nature, extent and potential impact of climate change.

However, the authors, who are all experts on climatology and are involved in the ongoing discussion on recent research results, express different views as to the extent and rhythm of climate change and the reliability of projections into the future. These differences of opinion intrigue the public: Who is right? Who is wrong?

Our contemporary global society is confronted with the urgent need to find a response to climate change. The question remains: Will we be more successful in enduring than previous civilisations?

This book examines a central issue of public concern. Written by internationally acclaimed American and French experts, it demonstrates the wide consensus on the issue of climate change, as well as the differences in points of view that divide French and American scientists. The authors also show how on various occasions, particularly in Europe and the United States, citizens and the scientific community have acted together in response to the challenge that climate change poses to society.

Jean-Louis Fellous is a Coordinator for the European Space Agency's programmes on Earth Observation for Climate, Environment and Security. He is the executive secretary of the Committee on Earth Observation Satellites (CEOS) and co-president of the international Joint Commission for Oceanographic and Marine Meteorology (JCOMM). He is the author of Avis de tempête. La Nouvelle donne climatique (2003).

Catherine Gautier has taught in the Geography Department of the University of California at Santa Barbara since 1990; she was the director of the Institute for Computational Earth System Science from 1996 to 2002.