and Summary -- Past and Current Climate Change -- Projections of Future Anthropogenic Climate Change -- Climate-related Change in Terrestrial and Freshwater Ecosystems -- Climate-related Marine Ecosystem Change. Climate change and its impact on our life, our en- Global Energy and Water Cycle Experiment vironment and ecosystems in general, are in these (GEWEX) of the World Climate Research P- days at the forefront of public concern and polit- gram (WCRP). ical attention. The Intergovernmental Panel on The ?rst chapter of the book places the initia- Climate Change (IPCC) reports have amply doc- tive in context, clari?es a few key concepts and umented that anthropogenic climate change is an summarizes the key results; Chapters 2 to 5 d- ongoing trend, which will continue into the future ument the knowledge about recent and ongoing and may be associated with grave implications. changes in meteorological, oceanographical, hy- Thus, one conclusion to be drawn is clear - the drological and cryospherical variables, about s- driver for this climate change should be curtailed nariosofpossiblefutureclimaticconditions,about to the extent socially responsible and sustainable. changes in terrestrial and freshwater ecosystems, We need to strongly reduce the emissions of radia- and about changes in marine ecosystems. A series tively active gases into the atmosphere. of appendices provide background material rele- However, even the most optimistic emission re- vant in this context. ductionscenariosenvisiononlyalimitedsuccessin Two remarkable aspects of the BACC init- thwarting climate change. What is possible is to tive should be mentioned.