Groundwater Dependent Ecosystems (GDEs) frequently exhibit rich biological diversity and can provide enormous economic wealth. In recent years, GDEs in many industrialized countries have shown signs of serious degradation, primarily the result of groundwater abstraction and pollution. Many such systems, including a number of well documented cases in Eastern Europe, are no longer sustainable. As a consequence, the conservation and sustainable management of GDEs has emerged as one of the most urgent environmental research priorities of our time. A large percentage of the world's population lives in cities and either depends on, or is affected in some way, by groundwater. Moreover, groundwater has become a very important and complex issue that attracts the interest of many diverse stakeholders. Many problems related to groundwater and ecosystems are shared by countries throughout the world...

Peter Meisen, Past President, Global Energy Network Institute, asked in 1997, “What if there was an existing, viable technology, that when developed to its highest potential could increase everyone’s standard of living, cut fossil fuel demand and the resultant pollution?” After 23 years of sustained effort by the global scientific community, this is becoming a reality. The technology to extract heat from granite has been revolutionized in the last few years. The classical method of creating fracture networks by hydrofracturing is being replaced by a closed-loop method where fluids are not in contact with the hot granite. Supercritical CO2 is replacing water as a circulating fluid. Certainly, the future energy road is going to be led by highly radiogenic granites. While hydrothermal sources are site-specific and have their limitations, EGS can be initiated anywhere on earth. EGS is removing all such obstacles and, in the future, will provide uninterrupted electricity for all. Energy-deficient countries can have surplus electricity; water-stressed countries can have a perennial freshwater supply; and countries can become food-secure and rise above poverty levels. Countries need not depend on energy imports and can independently evolve into carbon neutral or low carbon societies. The contributions made by experts will help researchers and investors to close the energy demand and supply gap in the very near future by tapping the unlimited energy of the Earth. Opportunities available for investors in Turkey are well documented with field, geophysical, and geochemical data and information on the energy generating capacity of the granite intrusive spread over a cumulative area of 6,910 km2 in western Anatolia. With the signing of the Global Geothermal Alliance (GGA) by several countries during the December 2015 CoP 21 (Conference of Parties) summit in Paris, countries are obliged to reduce CO2 emissions by increasing the footprint of renewable energy in the primary source mix. Information provided in this book will lead the way to establishing a clean energy future for millions of people for sustainable development and help to mitigate crises arising due to food, water, and energy shortage issues. Academic and research institutes will benefit to a large extent from the expertise of the top contributors in this book. This information provided in this book will help to lay the foundation for super-hot EGS research in future.

National and global security can be assessed in many ways but one underlying factor for all humanity is access to reliable sources of water for drinking, sanitation, food production and manufacturing industry. In many parts of the world, population growth and an escalating demand for water already threaten the sustainable management of available water supplies. Global warming, climate change and rising sea level are expected to intensify the resource sustainability issue in many water-stressed regions of the world by reducing the annual supply of renewable fresh water and promoting the intrusion of saline water into aquifers along sea coasts, where 50% of the global population reside. Pro-active resource management decisions are required, but such efforts would be futile unless reliable predictions can be made about the impact of the changing global conditions on the water cycle and the quality and availability of critical water reserves. Addressing this wide spectrum of issues, a team of expert authors discusses here the impacts of climate change on the global water resources, the long-term resource management goals at global and local scales, the data requirements and the scientific and technical advances necessary to mitigate the associated impacts.

In the region comprising Turkey and Greece, people have been using water from geothermal sources for bathing and washing of clothes since ancient times. This region falls within the Alpine-Himalayan orogenic belt and hence is a locus of active volcanism and tectonism and experiences frequent seismic events. This volcanic and tectonic activity has given rise to over 1500 geothermal springs. Its importance was recognized decades ago and the geothermal water is now being utilized for district heating, industrial processing, domestic water supply, balneology and electric power generation. The geothermal potential in this region is large. In Turkey alone it is estimated to be more than 31500 MWt while the proven potential is 4078 MWt. At present 2084 MWt is being utilized for direct applications in Turkey and 135 MWt in Greece. In Turkey electricity is produced for 166 MW installed capacity, whereas in Greece geothermal energy is presently not used for electricity production despite its potential. This book discusses the geochemical evolution of the thermal waters and thermal gases in terms of the current volcano-tectonic setting and associated geological framework that makes the region very important to the geothermal scientific community. The book explains, in a didactic way, the possible applications, depending on local conditions and scales, and it presents new and stimulating ideas for future developments of this renewable energy source. Additionally, the book discusses the role(s) of possible physicochemical processes in deep hydrothermal systems, the volatile provenance and relative contributions of mantle and crustal components to total volatile inventories. It provides the reader with a thorough understanding of the geothermal systems of this region and identifi es the most suitable solutions for specifi c tasks and needs elsewhere in the world. It is the fi rst time that abundant information and data from this region, obtained from intensive research during the last few decades, is unveiled to the international geothermal community. Thus, an international readership, in the professional and academic sectors, as well as in key institutions that deal with geothermal energy, will benefit from the knowledge from geothermal research and experiences obtained from the Aegean Region.

National and global security can be assessed in many ways but one underlying factor for all humanity is access to reliable sources of water for drinking, sanitation, food production and manufacturing industry. In many parts of the world, population growth and an escalating demand for water already threaten the sustainable management of available water supplies. Global warming, climate change and rising sea level are expected to intensify the resource sustainability issue in many water-stressed regions of the world by reducing the annual supply of renewable fresh water and promoting the intrusion of saline water into aquifers along sea coasts, where 50% of the global population reside. Pro-active resource management decisions are required, but such efforts would be futile unless reliable predictions can be made about the impact of the changing global conditions on the water cycle and the quality and availability of critical water reserves. Addressing this wide spectrum of issues, a team of expert authors discusses here the impacts of climate change on the global water resources, the long-term resource management goals at global and local scales, the data requirements and the scientific and technical advances necessary to mitigate the associated impacts.

Many problems related to groundwater and ecosystems are shared by countries throughout the world and there is growing recognition that much can be gained by co-operation on an international scale. This is no time for complacency and it is critical that key problems be identified, that the potential consequences of these problems be understood, and that the development of solutions begins urgently. Important data gaps must be recognized and filled without delay.