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This book starts by discussing the global flows of energy and materials and changes caused by human activities. It then examines the limitations of anthropogenic energy and material flows and the consequences for the development of human society. Different scenarios for lifestyle patterns are correlated with the future development of the global energy supply and climate. As it provides a process engineering approach to the Earth system and global development, readers should have a basic understanding of mathematics, physics, chemistry and biology.
This second edition also reflects new developments since the original publication: increases in anthropogenic energy and material flows due to significant economic growth in certain parts of the world, and recent changes in energy policy and technological development countries, such as Germany (the Energiewende, or transition to renewable energy sources), where goals have been defined and measures initiated for a future energy supply without fossil and nuclear sources. As such, it offers a valuable resource for undergraduate and graduate students as well as practicing experts alike.

### Chapter 1. Introduction and Fundamentals

This chapter is introduced by a discussion of the relevance of environmental effects caused by humans and the concept of sustainability. These effects on a global scale are a major challenge for human societies. The second part of this chapter deals with the definition of systems, their balances, and their properties with special emphasis on dynamic and feedback situations. The third part describes how systems respond energetically to processes in them and changes of their surroundings. Classical thermodynamics distinguishes between different kinds of energies that can be interconverted without altering the sum of all energies. As different kinds of energy do not have the same quality and low-level energy cannot be completely transformed to higher levels, second-law analyses using the concepts of entropy and exergy are required. Non-equilibrium thermodynamics is devoted to real systems far away from equilibrium, where fluctuations and instability are of great importance. Entropy and irreversibility that destroy order near equilibrium can create order in systems far from equilibrium.
Georg Schaub, Thomas Turek

### Chapter 2. Biogeosphere as Environment for Life

The properties of the Earth and especially of the biogeosphere as an environment that has allowed for the development of life and human civilization are discussed in this chapter. The first part describes the position of the Earth in the solar system and the present conditions on Earth as a whole as well as in its constituents (crust, ocean, and atmosphere). The second part deals with the driving forces for historic and current changes in the biogeosphere and the resulting developments of the atmospheric composition and the global climate. Finally, the development of life on Earth and of the human civilization are briefly reviewed.
Georg Schaub, Thomas Turek

### Chapter 3. Energy Balance of the Earth

The energy transformations on Earth are discussed in this chapter. The Earth’s temperature is determined by the global energy balance between radiative energy coming from the Sun and radiative energy emitted back to space. The atmosphere has a strong additional impact on the global energy balance as it efficiently absorbs infrared radiation coming from the surface of the Earth. As a result of this greenhouse effect, the surface temperature is much higher than in the absence of the atmosphere. Life on Earth has the ability to convert energy received from the Sun into energy-containing chemical components via photosynthesis. The biosphere that is based on this mechanism is capable of changing energy-relevant properties of the Earth and alters the energy balance on a global scale. Also discussed are spatio-temporal variations of the conditions on Earth, which are caused by the movement of Earth around the Sun and its rotation. Finally, selected simple feedback models of the Earth are treated to describe important general aspects of the global climate system.
Georg Schaub, Thomas Turek

### Chapter 4. Global Material Cycles

This chapter discusses prominent examples of global material cycles. This is of major significance in order to understand potential perturbations of the natural material cycles caused by man’s production or use of energy. As selected examples, carbon, water, nitrogen, and oxygen cycles will be treated, and in addition aspects of some other material cycles (sulfur, phosphorus, chlorine) as well as interactions of these cycles. The Earth as a closed system is represented by a selection of several open (sub-)systems which exchange material and energy by various processes. Human activities, in many cases, have already had a strong impact on the natural material cycles, often with deleterious impact on ecosystems. In particular the global carbon system with its relatively small natural atmospheric reservoir is under severe threat through anthropogenic carbon dioxide emissions. It is evident that there is a strong incentive to decouple future energy supply from fossil organic material combustion.
Georg Schaub, Thomas Turek

### Chapter 5. Anthropogenic Material and Energy Flows

During most of the history of human civilization, energy and material flows caused by human activities were insignificant in comparison to natural flows. This has changed during the past 250 years, when the global population increased greatly and began to use fossil raw materials in large quantities for energy generation. This chapter starts with the history of natural changes in the global carbon cycle during the past 500 millennia. These changes are compared with the material and energy flows caused by humans, as developed during the past 250 years. Germany is treated as an example for a national economy with the characteristic energy flows and energy sources of an industrialized country. Energy flows are commonly structured in different sectors, which helps to identify areas of higher and lower values of energy demand. The sectors of industry, transport, residential, and business and services, each exhibit characteristic energy demand values at present, both in terms of quantity and form of energy. Given the high relevance of fossil energy resources today, the correlation of energy flows and carbon flows—the latter leading to $$\mathrm{{CO}_{2}}$$ emissions—is discussed.
Georg Schaub, Thomas Turek

### Chapter 6. Limits for Anthropogenic Material and Energy Flows

For human societies, there are various limiting factors for development, such as availability of food, raw materials for producing goods, capital for investment, environmental effects, and/or international conflicts. In the context of this book, this chapter introduces five factors representing the supply of energy and raw materials, as well as environmental effects on regional and global scales. It remains an open question, which of these factors will become the most determining and when.
Georg Schaub, Thomas Turek

### Chapter 7. Approaches to Global Development

As a consequence of the material and energy flow analyses discussed in the preceding chapters, this chapter presents general criteria for future development and related technology options. As the most important criterion, human activities in energy conversion should make optimum use of natural cycles, instead of depending on non-renewable fossil raw materials. However, this is possible only if technologies are developed that can cope with the low average flux densities of natural energy and material flows. Examples are discussed for the electricity and heat generation sectors, mobility and transport, with a short discussion of bioenergy and hydrogen. As a means for better understanding the contribution of individual life styles, per-capita energy demand values and $$\text {CO}_{2}$$ emission patterns are presented, which are easy to use in personal case studies. Global strategies for development in terms of protecting the global biosphere are introduced, based on scenarios that can be found in the open literature, regarding future developments of emissions and responses of the global climate system. The transition process to a non-fossil energy supply system as recently initiated in Germany is also outlined.
Georg Schaub, Thomas Turek

### Chapter 8. Conclusions

This chapter presents a conclusive summary of the analyses and discussions given in the book. The conclusions reflect the high complexity of the problem and try to focus on the most important aspects. In this sense, it cannot be complete, but is intended to serve as a general guideline.
Georg Schaub, Thomas Turek