This book collects most of the contributions prepared for the NATO Advanced Research Workshop (ARW) on Environmental Challenges in the Mediterranean 2000-2050. The ARW took place in Madrid from 2 to 5of October 2002. Scholars and researchers from North and South ofthe Mediterranean and other countries from NATO gathered in Madrid for discussing several important factors that could affect Mediterranean security in the next 50 years. In this regard the first chapter presents the different debates regarding environmental security that took place in the last decade. This chapter is an introductory chapter and takes into account the possible audience in the Southern Mediterranean and the wishes ofsome contributors. For this reason the chapter deals in extenso with the question ofhuman security and the different approaches. The ARW dealt with issues that may affect the supply of fundamental goods for human living. To this end the complex question ofclimate change, its impact in the Mediterranean, the predicted increase in temperatures and predictions about rainfall are analysed. As part of this approach a chapter about solar variability and climate change is also added.