Global Environmental Change

A Natural and Cultural Environmental History

Antoinette Mannion

• Publisher: Routledge
• Year: 2014
• eBook ISBN: 9781317889397
• Topic: Physical Sciences
• Subtopic: Geography
• Index: Geography

Now in its second edition. This text has been extensively revised and rewritten to reflect the growth in environmental research during the last decade. Human-induced environmental change is occurring at such a rapid rate that, inevitably, the fundamental processes involved in biogeochemical cycling are being altered.
Global Environmental Change considers alterations to the biogeochemical cycles of carbon, nitrogen, sulphur and other elements as a result of industrial/technological development and agriculture, which have significantly altered the natural environment. The book adopts a temporal and spatial approach to environmental change, beginning with the natural environmental change of the Quaternery period and continuing with the culturally-induced change since the inception of agriculture 10,000 years ago.

CHAPTER 1		Nature, culture and environmental change

1.1 Introduction

Environmental change is a continual process that has been in operation since the Earth first came into existence some 5 × 10⁹ years ago. From the time of this genesis, dynamic systems of energy and material transfer have operated at local, regional and global scales to effect gradual, and sometimes catastrophic transformations of the atmosphere, hydrosphere, lithosphere and biosphere. For most of Earth history the agents of change have been the elements of wind, ice, water, tectonic forces, micro-organisms, plants and animals; all of them have operated reciprocally within dynamic ecosystems that characterise the biosphere. Environmental change and the evolution of organisms occurred as stimuli were generated either indigenously through mutual dependence or exogenously due to the Earth’s orbital geometry and/or changes in the Sun’s luminosity.

Some 5 × 10⁶ years ago, however, a new agent of environmental change emerged. This was the first hominid species (see Fig. 4.2) from which Homo sapiens sapiens, i.e. modern humans, eventually evolved. Initially this species was an integral component of the biosphere like any other animal but the capacity of humans to develop technology with which to turn Earth surface components into resources has rendered the species a particularly powerful agent of environmental change. As knowledge has progressed and as science and technology have developed, society has achieved both an improved insight into the processes and consequences of environmental change and the means of altering the environment drastically. This can occur directly through activities such as habitat loss and urban expansion. There is also much inadvertent environmental change through agencies such as pollutants from agriculture and industry.

Since Homo sapiens sapiens evolved, and quite when this occurred is disputed, the relationship between nature, i.e. the biota, and environment has changed. This is particularly so for the past 10 K years, since when humans have attempted to dominate ecosystem processes. The relationship has become tripartite rather than bipartite. Nature and environment have been joined by culture, i.e. the human element. In addition, the manifestation on the ground of this tripartite relationship has changed spatially and temporally. The changing relationship between environment, nature and culture is the theme of this book.

1.2 The development of ideas about environmental change

Human beings must always have been concerned with their environment since it was their immediate surroundings that provided the resources necessary for survival. As heterotrophs, humans need to acquire energy, which, as integral components of the biosphere, they do by selectively consuming plants and animals. They also exploit substances derived from the Earth, collectively known as mineral resources, and in the later part of their history they have turned to the fossil plant communities of past eons, i.e. coal, oil and natural gas, to obtain fuel energy.

For preliterate times the only direct testimony to the relationship between people and their environment lies in prehistoric cave paintings. Examples include the recently discovered Chauvet cave in the Ardèche of France, where the oldest rock paintings in the world are found and which are dated at ca. 32 K years, and the famous caves of Lascaux in the Dordogne, the paintings in which are dated to ca. 17 K years ago. These works of art reflect the lives of hunter-gatherers who lived during the time of the last major ice advance and depict the prey and predators of the period, e.g. aurochs, deer, horses and wolves.

With the rise of the ancient Mediterranean civilisations of Greece and Rome came the first written accounts of places, trade routes, crops, etc. Herodotus (ca. 485–425 BC), a Greek scholar often described as the father of history, recorded a variety of environmental features such as the regime of the River Nile, and later another Greek scholar, Aristotle (384–322 BC) advanced the idea of a spherical instead of a flat Earth. He also introduced mathematical concepts for the measurement of global features such as latitude and longitude. This tradition was continued by Eratosthenes (276–194 BC), who produced a massive eight-volume work entitled Geography containing details of map projections and methods for the calculation of the Earth’s dimensions. Similarly Strabo (64 BC to AD 20), a Roman scholar, produced a seventeen-volume work entitled Geographica, which examined much of the then known world and involved a recognition of dualism in geography: that of people (human geography) and place (physical geography).

Ideas changed little during the Middle Ages when European scholars returned to the concept of a flat Earth to conform with ecclesiastical teaching. Once again the civilisations of the Mediterranean, principally the Arab world, augmented the information of the Greeks, while in China geographical knowledge was well advanced, although inaccessible to European scholars until Marco Polo’s (1255–1325) expeditions. The Renaissance, however, brought a scientific revival to Europe, including renewed interest in Ptolemy’s Geography which provided explorers such as Columbus with a basic mathematical approach to location. Travellers provided a potpourri of descriptive information on people and places which, in addition to the publication of Mercator’s map projections in 1569, led to the production of the first globes and new maps.

The bipartite nature of geography, first intimated in Strabo’s work, involving human and physical divisions, was formalised by a Dutch scholar Varenius (1622–1650), who originated the ideas of regional or ‘special’ geography and systematic or ‘general’ geography. The latter, he advocated, could be studied using natural laws and was thus a more exact science. This approach was continued by Immanuel Kant (1724–1804) who argued strongly for a scientific base to the study of geographical or environmental phenomena, which he considered to be just as essential as the exact sciences. This stance was continued by von Humboldt (1769–1859), who developed an inductive approach to explaining natural phenomena. A renowned explorer, von Humboldt published a five-volume work entitled Kosmos (1845–1862) in which he attempted not only to describe natural phenomena, such as rocks, plants and animals, but to explain their occurrence and to undertake comparative studies.

However, the deductive and mechanistic philosophy earlier advocated by Newton (1642–1727) was continued in the work of Charles Darwin (1809–1882). In 1859 he published his classic work On the Origin of Species in which he charted the development of life, and advanced theories on evolution. For the student of environmental change this is a most significant publication since it suggests a relationship between environment and organisms and, moreover, charts a developmental sequence. If organisms changed due to environmental parameters, then environment itself must have changed. Although many of these scholars held views that were inherently deterministic, i.e. a belief in the overall control of environment, especially climate, on human activity the term ‘environmental determinism’ originated with the work of Darwin that highlighted the operation of the laws of nature in relation to organisms. Social scientists and philosophers such as Herbert Spencer (1820–1903) began to apply Darwin’s ideas on the environmental control of biota to humanity. Spencer suggested there were many similarities between organisms and societies and that to be successful only the ‘fittest’ in a free-enterprise system would survive. Indeed it was Spencer (1864) who first coined the phrase ‘survival of the fittest’. Many notable geographers and natural scientists were profoundly influenced by these ideas, including William Morris Davis (see below). Most importantly these ideas invoked changing landscapes and societies. So it is perhaps no coincidence that many notable scientists began to advance theories relating to environmental change at much the same time and, perhaps more pertinently, though not explicitly, introduced the idea of dynamism into environmental studies.

By the end of the eighteenth century the diluvial theory, the proposal that the Biblical flood was a major agent in shaping the face of the Earth, was being questioned. Scientists such as James Hutton and John Playfair were among the first to advance the theory of glaciation. Hutton’s observations of erratic boulders in the Jura Mountains, noted earlier by a Swiss minister, Bernard Friederich Kuhn, led him to invoke glacier ice as the agent of transportation (Hutton, 1795). Nevertheless, it was not until the 1820s that the glacial theory became more widely proposed and, although Agassiz presented the theory to the Swiss Society of Natural Sciences in 1837, numerous earlier workers had already published evidence for glacial processes. These included Jean-Pierre Perraudin, a Swiss mountaineer, Jean de Charpentier, a naturalist, and Ignace Venetz, a highway engineer, all of whom proposed that Swiss glaciers had extended beyond their present positions. Despite this wider acclaim the glacial theory was still rejected by many in favour of Charles Lyell’s (1833) explanation for erratics, drift, etc., as being the products of floating icebergs. This idea was also given credence by reports of boulder-containing icebergs from contemporary explorers like Darwin himself.

However, William Buckland, who was appointed professor of geology at Oxford in 1820, was the first to acknowledge that neither the diluvial nor iceberg drift theories could provide satisfactory explanations for all the evidence and eventually, in 1840, he and Charles Lyell accepted Agassiz’s views. Despite residual resistance in the scientific community, the glacial theory became widely accepted by the mid-1860s. By this time further developments were in hand. Evidence for changing sea levels was compiled by Jamieson (1865) based on evidence from Scotland, North America and Scandinavia; von Richtofen (1882) advanced a windborne origin for loess deposits; Gilbert (1890) presented evidence to show that the Great Salt Lake of Utah is only a remnant of a much larger lake, and in Britain Archibald Geikie (1863) suggested the idea of multiple glaciation. Multiple glaciation involved several cold stages or glacials, separated by warm stages or interglacials and was further substantiated by James Geikie (1874). Moreover, Penck and Brückner (1909) interpreted Alpine terrace sequences in terms of oscillating warm and cold stages.

Inevitably, as evidence on environmental change accrued, attention also focused on the underlying cause of climatic change. Adhémar, a French mathematician, was the first to involve the astronomical theory in studies of the ice ages. In 1842 he proposed that changes in the orbit of the Earth round the Sun may be responsible for climatic change of such great magnitude. A similar approach was advanced by a Scottish geologist, James Croll, who in 1864 suggested that changes in the Earth’s orbital eccentricity might cause ice ages. This theory he explained in full in his book Climate and Time (Croll, 1875). This theory was accepted by both Archibald and James Geikie, giving it much credence in the geological community. Owing to the inability of geologists to substantiate Croll’s predictions in the absence of reliable dating techniques, his theories fell into disuse until their revival in the 1920–1940 period by Milutin Milankovitch, a Yugoslavian astronomer (Section 2.6). Although numerous other theories for causes of climatic change have been proposed, Milankovitch’s ideas have become widely accepted since the 1950s, when evidence from deep-sea core stratigraphy was first obtained.

The late eighteenth and early nineteenth centuries also witnessed the establishment of new methods, based principally on biological remains, for examining the nature of environmental change, and thus establishing the general field of palaeoecology. Plant macrofossils were among the first biological indicators to be used to interpret Quaternary palaeoenvironments. Blytt (1876) and Sernander (1908), both Scandinavian geologists, used macrofossils in peat deposits to explain the forest history of northwest Europe and associated climatic changes. Similarly, von Post (1916) developed pollen analysis as a means of examining environmental change. The two are complementary techniques and have played a major role in examining vegetation change during interglacial stages and the post-glacial period, as will be shown in Chapter 2. Numerous other fossil groups of plants and animals have also been used as indicators of past environments in the last 50 years; see the review in Berglund (1986).

Apart from the inception of the glacial theory and its development during the nineteenth century, there were other notable developments in the early twentieth century, which also significantly altered scientific thought. For example, Davis in 1909 advanced a theory which he called ‘the geographical cycle’. This encapsulates an idealised landscape originating with mountain uplift and culminating in lowland plains. Although this is no longer an accepted theory, it is historically significant insofar as it invokes the idea of continual processes and the idea of continual change. This theoretical treatment of landscape development has a counterpart in ecological studies. In 1916 Clements wrote: ‘As an organism the climax formation arises, grows, matures and dies. Its response to the habitat is shown in processes or functions and in structures which are the record as well as the results of these functions’. Thus Clements expressed the nature of vegetation communities as ever-changing entities, and while there is much debate about the acceptability of his ideas (Mannion, 1986), he was responsible for injecting the idea of dynamism into ecological systems. These scholars were influenced by environmental determinism (see above), a philosophy tha...

Table of contents

• Cover
• Title Page
• Dedication
• Copyright Page
• Table of Contents
• Preface
• Acknowledgements
• Chapter 1 Nature, culture and environmental change
• Chapter 2 Quaternary geology and climatic change
• Chapter 3 Environmental change in the late-and post-glacial periods
• Chapter 4 Prehistoric communities as agents of environmental change
• Chapter 5 Environmental change in the historic period
• Chapter 6 Environmental change due to post-1700 industrialisation
• Chapter 7 The environmental impact of agriculture in the developed world
• Chapter 8 The environmental impact of agriculture in the developing world
• Chapter 9 Other agents of change: forestry, recreation and tourism, biotechnology
• Chapter 10 Conclusion and prospect
• References
• Index