Preface to the First Edition

Half a century ago, Christian Junge, the founding “father” of atmospheric chemistry, summarized the existing knowledge in his field of research. In 1960, Junge counted only 75 research articles dealing with atmospheric chemistry and radioactivity (Junge 1958, 1963). At present, the publication rate and number of researchers in atmospheric chemistry are orders of magnitude greater. Many major advances have been made since then. For example, in the early 1970s, the role of OH radicals in oxidizing gases, leading to their removal from the atmosphere, was discovered. The necessary ingredients to produce OH are ozone, water vapor, and ultraviolet B (UV-B) solar radiation. The catalytic role of NO in producing ozone was also recognized in the early 1970s. Until that time it was generally believed that tropospheric ozone was produced in the stratosphere and transported downward into the troposphere. The feedstocks for the creation of ozone are CO, CH4, and many biogenic gases. Both natural and anthropogenic processes are responsible for their emissions. Although the main photochemical chain reactions are reasonably well known, their quantification needs much further research. They all are parts of the biogeochemical cycles of carbon, nitrogen, and sulfur. They can also play a role in climate, as does particulate matter (PM), which, contrary to the greenhouse gases (CO2, CH4), tends to cool the Earth and atmosphere. In his book, Detlev Möller gives a thorough overview of the main chemical processes that occur in the atmosphere, only a few of which were mentioned earlier. The novel title of this book, Chemistry of the Climate System, should direct the attention of the reader to the fact that understanding atmospheric chemistry is incomplete without considering interfacing neighboring reservoirs such as the hydrosphere, lithosphere, and biosphere. An overview of the topics treated is provided in the introduction. It emphasizes that drawing strong borderlines between disciplines makes no sense; this is also valid for the various systems because they overlap and the most important processes can happen at their interfaces. Therefore, chemistry of the climate system combines atmospheric with water, soil, and biological chemistry. Another general approach of this book lies in the incorporation of historical facts: despite the orders of magnitude more publications each year at present than in the past, we should not forget that careful observations were made and serious conclusions drawn by many of our scientific ancestors. The text has its roots in a book written in German, entitled Luft and published by De Gruyter in 2003. Although the text was entirely rewritten and many chapters were replaced, the main emphasis on regarding the atmosphere as a multiphase system is essentially unchanged. Moreover, by adding interfacial chemistry, the system is enlarged into a multireservoir system, encompassing the climate system. Ultimately, however, the central focus is chemistry. The author avoids using the term environ-