Gerrit Lohmann - Böcker

This open access book presents interviews with high-profile climate scientists about state-of-the-art research questions. Consequences of climate change have become more and more visible and are now regularly discussed in political and societal debates. While climate scientists have been warning about potential consequences of anthropogenic greenhouse gas emissions for decades, their call for action has not sufficiently been heard for long. Meanwhile, the field of climate science has grown significantly and become more interdisciplinary. As a result, more sophisticated technologies, higher data availability as well as more advanced climate models have made the fundamental message stronger than ever: The impact of human activity on the Earth’s climate is clear and severe and irreversible consequences already occur all over the world. The authors were given the opportunity to talk to leading climate scientists from different disciplines. These do not only include theoretical physics, paleo-research, and climate modelling, but also cover the role of the biosphere, extreme weather events, and attribution science. Additionally, the interviews also address the political dimension of climate science.

This book describes the latest advances at the Helmholtz “Earth System Science Research School” where scientists from the Alfred Wegener Institute in Bremerhaven, the University of Bremen, and the Jacobs University are involved in research.One of the greatest challenges is understanding ongoing environmental changes. The longer the time scale the more components of the Earth system are involved, e.g. interannual and decadal variations are related to the coupled atmosphere-ocean-sea ice system, whereas longer variations like glacial-interglacial or Cenozoic transitions involve the carbon cycle, ice sheets and gateways. In order to get deep insights into Earth system science, observations, remote sensing, past environmental data, as well as modeling need to be integrated. These different approaches are traditionally taught in separated disciplines at bachelor and master levels. It is, therefore, necessary to bring these disciplines together in PhD programs.

An Introduction to the KIHZ Project The description of the climate system and the quantification of its natural variability and dynamics is essential to assess an ongoing anthropogenic cli­ mate change and to validate climate and biogeochemical models to allow for reliable projections into the future. Because the spatio-temporal coverage of direct meteorological observations is rather limited, high-resolution and ab­ solutely dated climate archives represent the only key to a quantification of seasonal to millenial climate variations in the past. Furthermore, climate mod­ els provide insights into the major processes and causes relevant for climate variability on these time scales. Both approaches represent one side of the same medal, however melting both sides down to one combined effort is often hampered by obstacles defined by the different nature of the approaches. For instance, General Circulation Models (GCMs) per se deal with spatially resolved data representing real climate variables in the model world (such as temperature or precipitation) with each model run reflecting one possible realization of climate history under given boundary conditions. In contrast, the records of natural climate archives are influenced by climate variations as they took place in reality, however, are often representative of local climate conditions only. Moreover, the climate information deduced from natural archives is in nearly all cases based on climate proxies, whose relationship to real climate variables, the so called transfer function, has to be established beforehand.

An Introduction to the KIHZ Project The description of the climate system and the quantification of its natural variability and dynamics is essential to assess an ongoing anthropogenic cli­ mate change and to validate climate and biogeochemical models to allow for reliable projections into the future. Because the spatio-temporal coverage of direct meteorological observations is rather limited, high-resolution and ab­ solutely dated climate archives represent the only key to a quantification of seasonal to millenial climate variations in the past. Furthermore, climate mod­ els provide insights into the major processes and causes relevant for climate variability on these time scales. Both approaches represent one side of the same medal, however melting both sides down to one combined effort is often hampered by obstacles defined by the different nature of the approaches. For instance, General Circulation Models (GCMs) per se deal with spatially resolved data representing real climate variables in the model world (such as temperature or precipitation) with each model run reflecting one possible realization of climate history under given boundary conditions. In contrast, the records of natural climate archives are influenced by climate variations as they took place in reality, however, are often representative of local climate conditions only. Moreover, the climate information deduced from natural archives is in nearly all cases based on climate proxies, whose relationship to real climate variables, the so called transfer function, has to be established beforehand.

Earth system science is traditionally split into various disciplines (Geology, Physics, Meteorology, Oceanography, Biology etc.) and several sub-disciplines. Overall, the diversity of expertise provides a solid base for interdisciplinary research. However, gaining holistic insights into the Earth system requires the integration of observations, paleoclimate data, analysis tools and modeling. These different approaches of Earth system science are rooted in various disciplines that cut across a broad range of timescales. It is, therefore, necessary to link these disciplines at a relatively early stage in PhD programs. The linking of ‘data and modeling’, as it is the special emphasis in our graduate school, enables graduate students from a variety of disciplines to cooperate and exchange views on the common theme of Earth system science, which leads to a better understanding of processes within a global context.

Compared to other books, this work provides a much more compact view of the language, while also placing the language-elements in a more applied setting, by providing examples related to numerical computing and more advanced Input/Output facilities for Earth system sciences.

This work provides a short "getting started" guide to Fortran 90/95. The main target audience consists of newcomers to the field of numerical computation within Earth system sciences (students, researchers or scientific programmers). Furthermore, readers accustomed to other programming languages may also benefit from this work, by discovering how some programming techniques they are familiar with map to Fortran 95. The main goal is to enable readers to quickly start using Fortran 95 for writing useful programs. It also introduces a gradual discussion of Input/Output facilities relevant for Earth system sciences, from the simplest ones to the more advanced netCDF library (which has become a de facto standard for handling the massive datasets used within Earth system sciences). While related works already treat these disciplines separately (each often providing much more information than needed by the beginning practitioner), the reader finds in this book a shorter guide which links them. Compared to other books, this work provides a much more compact view of the language, while also placing the language-elements in a more applied setting, by providing examples related to numerical computing and more advanced Input/Output facilities for Earth system sciences. Naturally, the coverage of the programming language is relatively shallow, since many details are skipped. However, many of these details can be learned gradually by the practitioner, after getting an overview and some practice with the language through this book.