Much of the evidence related to climate change is concerned with data from particular locations or small areas. However data captured from remote sensing systems in space and covering the whole earth can yield evidence of climate change from extensive areas. In this book international experts consider the potential value of such data addressing the problem of calibration to ensure that detected changes do not arise from drift in the calibration of the instrument or changes in the calibration coefficients from one model to another in a series of nominally identical modes. There will be some consideration of large international projects devoted to the study of cloud climatology from the archived meteorological satellite data and also of vegetation indices derived from the global sets, principally the AVHRR. The related question of the use of archived satellite data to improve the specification of surface conditions, particularly of vegetated land areas in global climate models will also be considered. This book ends with a discussion of the future role of satellite data, including data from new high-resolution instruments that are expected to be launched in the near future.