Carbon and Its Domestication (eBook)

Contents 7
List of Figures 9
List of Tables 11
Preface 13
Acknowledgements 15
1 INTRODUCTION 17
1.1 What is carbon? 18
1.2 Why is carbon so important? 22
1.3 Carbon and climate 23
1.4 Carbon and the environment in the last 3 million years 27
1.5 Carbon and technology through prehistory and history 30
1.6 Carbon and development 33
1.7 Carbon and the future 37
2 THE CHEMISTRY OF CARBON 39
2.1 The mineral world 41
2.2 Organic compounds 43
2.3 The biogeochemistry of carbon 67
3 THE BIOLOGY OF CARBON 75
3.1 The web of life 76
3.2 Domain Archaea 82
3.3 Domain Bacteria 85
3.4 Domain Eukaryote 88
3.5 Viruses etc. 98
3.6 Vital processes 99
3.7 Food chains and food webs 110
4 THE GEOLOGY OF CARBON 115
4.1 Carbon, life and climate: the last 5 x 10 9 years 116
4.2 Sedimentary rocks 136
4.3 Coal 138
4.4 Oil (petroleum) and natural gas 141
4.5 Wetlands 144
5 THE HISTORY AND CONSEQUENCES OF CARBON DOMESTICATION 147
5.1 The harnessing of fire 149
5.2 The origins and spread of agriculture 154
5.3 Carbon exchanges during the Holocene 160
5.4 History of fossil-fuel use and industrialization 165
5.5 Pollution history 172
5.6 Biotechnology 175
6 THE GEOGRAPHY OF CARBON 179
6.1 World ecosystems 180
6.2 Marine ecosystems 197
6.3 The alteration of the world’s biomes 201
6.4 Measures of human impact 218
7 THE POLITICIZATION OF CARBON 225
7.1 Initiatives 1860 to 1939 228
7.2 Initiatives 1945 to the early 1970s 234
7.3 Green politics 238
7.4 Petropolitics and oil crises 240
7.5 NGOs 241
7.6 The UN, UNEP, international agreements and the Earth Charter 246
7.7 International initiatives on atmosphere/climate 251
7.8 The politics of biodiversity 257
7.9 Trade 259
8 CONCLUSION AND PROSPECT 265
8.1 Conclusion 267
8.2 Prospect 280
8.3 Envoi 299
8.4 Addendum 300
References 303
Index 319

2 THE CHEMISTRY OF CARBON (p. 23)

The fact that carbon has a valency of four, i.e. in the outermost shell surrounding the nucleus of the atom there are four electrons (see Section 1.1 and Figure 1.1), is the key to why carbon is so versatile. This outermost shell can accommodate eight electrons so each carbon atom has the capacity to share electrons with as many as four different atoms, including other carbon atoms. Thus carbon has the capacity to combine with many different elements to produce a vast array of compounds.

This is one reason why carbon is so important in nature and to society. Although most carbon compounds are associated with life and are thus referred to as organic, some carbon compounds are described as mineral because they are mainly, but not always exclusively, the product of geological rather than biological processes.

Truly mineral forms of carbon include its allotropes, comprising pure carbon in various structural forms, e.g. graphite, diamond and soot (see Section 1.1 and Figure 1.2). Such substances are, however, important because they have decorative or industrial uses and their extraction from geological environments is a wealth generating activity. Many other compounds containing carbon have also been formed geologically.

Such minerals include calcite (calcium carbonate), magnesite (magnesium carbonate) and dolomite (calcium magnesium carbonate). They can also be produced biologically as shells of marine organisms, which, as they become compressed through geological processes, produce limestone and chalk. Throughout Earth history the formation and weathering of these materials has played an important role in global climate because of the link between carbon dioxide in the atmosphere and shellproducing marine organisms.

These are discussed in Chapter 4 because of their importance in the geology of carbon burial and change in atmospheric composition. The fossil fuel reservoirs are also carbon-rich minerals which are linked with life. Their formation sequestered carbon from the active biosphere, a process that also had an impact on global climate because of the withdrawal of carbon dioxide from the atmosphere.They are also discussed in Chapter 4.

However, another relatively minor group of carbonates, including malachite (copper carbonate) and rhodochrosite (manganese carbonate), are considered here because they form through geological rather than biological processes. In contrast there are millions of organic compounds. These can be classified in many different ways including a basic subdivision into two groups: naturally occurring and synthetic compounds.

The former are found in living organisms, or in the environment having been produced by living organisms whilst synthetic compounds are so-called because they are artificial, i.e. they have been created in the laboratory and do not occur in nature. They have usually been created for a specific purpose, such as pharmaceuticals, crop protection chemicals and plastics. Usually they are complex molecules and comprise many carbon atoms combined with more than one other atom.

The huge range of organic compounds means that they can also be classified as simple or complex. Simple compounds contain one or two carbon atoms combined with between one and four atoms of other elements.