History, Change and Sustainability

Detlev Möller

• Publisher: De Gruyter
• Year: 2020
• eBook ISBN: 9783110559965
• Edition: 3
• Topic: Biological Sciences
• Subtopic: Environmental Science
• Index: Biological Sciences

Climate change is a major challenge facing modern society. The chemistry of air and its influence on the climate system forms the main focus of this book.

Vol. 2 of Chemistry of the Climate System takes a problem-based approach to presenting global atmospheric processes, evaluating the effects of changing air compositions as well as possibilities for interference with these processes through the use of chemistry.

1 Introduction

Out of the recognized complexity of nature arose the three basic sciences: physics, chemistry, and biology. Further progress in understanding of natural processes created numerous subdisciplines and cross-disciplines, termed with a variety of prefixes and combinations, often creating misunderstandings unless careful definitions are used. In order to overcome disciplinary borders, a new super-science was established, earth system science, to study the Earth as a system, with an emphasis on observing, understanding, and predicting global environmental changes involving interactions between biogeochemical compartments (land, atmosphere, water, ice, and biosphere) and anthropogenic compartments (societies, technologies, and economies). We will define the climate system to be a part of the earth system, with emphasis on the atmosphere but involving interactions between land, atmosphere, water, ice, biosphere, societies, and others. Hence, “Chemistry of the Climate System” is neither simply air nor environmental chemistry. Humans – by decoupling their life cycle from natural conditions – have altered “natural” biogeochemical cycles. The Russian geochemist Vladimir Ivanovich Vernadsky understood by noosphere (called anthroposphere by Paul Crutzen) a new dimension of the biosphere, developing under the evolutionary influence of humans on natural processes (Vernadsky 1926); consequently, Crutzen and Stoermer (2000) proposed to name the present epoch Anthropocene. Now it seems that humankind enters a nouveau régime climatique [new climatique regime] according to Bruno Latour (Latour 2015).

1.1 The human problem: a changing earth system

In recent decades, humans have become a very important force in the earth system, demonstrating that emissions and land-use change are the causes of many of our environmental issues. These emissions are responsible for the major global reorganization of biogeochemical cycles. With humans as part of nature and the evolution of a man-made changed earth system, we also have to accept that we are unable to remove the present system into a preindustrial or even prehuman state because this means disestablishing humans. The key question is which parameters of the climate system allow the existence of humans under which specific conditions. The chemical composition of air is now contributed by both natural and man-made sources. As will be discussed, large uncertainties in the estimations of global emissions (and subsequent regional gridded emission patterns) remain. Nevertheless, major regional and global environmental issues, such as acid rain, stratospheric ozone depletion, pollution by persistent organic pollutants (POPs), and tropospheric ozone pollution, resulting in adverse effects on human health, plant growth, and ecosystem diversity, were identified and controlled to different extents by various measures. Some key issues remain unsolved, such as the further increase of greenhouse gases (GHG), most importantly that of CO₂. With the growth of “megacities,” local pollution will have a renaissance, and this will inevitably contribute to regional and subsequently global pollution by large plumes, such as “brown clouds.” Thus, it is important to find answers to the following questions:

• What is the ratio between natural and man-made emissions?
• What are the concentration variations on different timescales?
• What are the true trends of species by man-made origin?
• What are the concentration thresholds for the effects (concerns different impacts) we cannot tolerate?

The chemical composition of air was changing since the settlement of humans. In addition to the scale problem (from local to global), we have to consider the timescale. Natural climate variations (e.g., due to ice ages) had a minimum timescale of 10,000 years. The man-made changes in our atmosphere over the last 2,000 years were relatively small before the 1850s. In the past 150 years (but almost all after 1950), however, the chemical composition has changed drastically. For many atmospheric compounds, anthropogenic emissions have grown to the same or even larger order of magnitude than natural ones. Because of the huge population density, the need (or consumption)³ of materials and energy has drastically forced the earth system.

The timescale of adaptation and restoration of natural systems is much larger than the timescale of man-made stresses (or changes) to the climate system. We should not forget that “nature” cannot assess its own condition. In other words, the biosphere will accept all chemical and physical conditions, even worse (catastrophic) ones. Only humans possess the facility to evaluate the situation, accepting it or not, and coming to the conclusion of making it sustainable. Under the aspect of chemical evolution, this volume also briefly outlines the role of humans in forcing the climate system. Let us define a sustainable society as one that balances the environment, other life forms, and human interactions over an indefinite time period.

Throughout the entire history of our planet, chemical, physical, and biological processes have changed the composition and structure of its reservoirs. Beginning with a highly dynamic inner earth 4.6 billion years ago, geochemical and geophysical processes have created the fundamentals for the Earth to become a habitat. With this, the formation of the hydrosphere was the most important precondition for the evolution of living matter. Despite large changes of the chemical composition of the atmosphere, hydrosphere and lithosphere (the geosphere) over the ages, these spheres or reservoirs are well defined concerning these essential parameters as interfaces, volume, mass, and others.

The British scientist James Lovelock together with Lynn Margulis developed the hypothesis that the Earth is a self-controlling system (Gaia: the earth goddess in Greek), and proposed that our present atmosphere is far from the chemical equilibrium that is assumed for other planets (Lovelock and Margulis 1974, Crutzen 2002). One expression of this is the difference in the redox potentials between biosphere (reducing medium) and atmosphere (oxidizing medium). It is believed that living organisms are responsible (to a large extent) for the chemical composition of the present atmosphere and, from the opposite point of view, the chemical composition of the atmosphere determines the biota. Remarkably, the composition of the biosphere is similar to that of the present atmosphere.

The term evolution⁴ was used first in the field of biology at the end of the nineteenth century. In the context of biology, evolution is simply the genetic change in populations of organisms over successive generations. Evolution is widely understood as a process that results in greater quality or complexity (a process in which something passes by degrees to a different stage, especially a more advanced or mature stage). However, depending on the situation, the complexity of organisms can increase, decrease, or stay the same, and all three of these trends were observed in biological evolution. At present, the word has a number of different meanings in different fields. Geological evolution is the scientific study of the Earth, including its composition, structure, physical properties, and history; in other terms, the Earth changes over time or the process of how the Earth has changed over time. The term chemical evolution is not well defined and is used in different senses.

Chemical evolution is not simply...

Table of contents

• Title Page
• Copyright
• Contents
• Preface to the first edition
• Authors preface to the third edition
• Authors preface to the second edition
• Prologue
• 1 Introduction
• 2 History of investigation and understanding the climate system
• 3 History of the climate system: the chemical evolution
• 4 A changing climate system
• 5 Climate change mitigation: global sustainable chemistry
• 6 Final remarks
• Appendix I List of acronyms and abbreviations found in literature
• Appendix II Quantities, units and some useful numerical values
• Appendix III Earth geological time scale
• References
• Name Index
• Subject Index
• Errata to Volume 1