1
Introduction

In this chapter the first issue that is addressed is the development of ideas over the last 300 years about the relationship between humans and their environment and in particular the development of ideas about how humans have changed their environment. The historical theme continues with a brief analysis of the changes that have taken place in human societies from prehistoric times onwards, culminating in the massive impacts that humans have achieved over the last three centuries and in particular during the so-called 'Great Acceleration' since the Second World War.

1.1 The Development of Ideas

To what extent have humans transformed their natural environment? This is a crucial question which became very important in the seventeenth and eighteenth centuries (Grove and Damodaran, 2006) as Western Europeans became aware of the ravages inflicted in the tropics by European overseas expansion. It was a theme that intrigued the eighteenth-century French natural historian, Count Buffon, in his colossal series, L'Histoire Naturelle. He can be regarded as the first Western scientist to be concerned directly and intimately with the human impact on the natural environment (Glacken, 1967). He contrasted the appearance of inhabited and uninhabited lands.

Studies of the torrents of the European Alps, undertaken in the late eighteenth and early nineteenth centuries, deepened immeasurably the realization of human capacity to change the environment. Jean-Antoine Fabre and Alexandre Surell studied the flooding, siltation, erosion, and division of watercourses brought about by deforestation in these mountains (Ford, 2016). Similarly Horace-Bénédict de Saussure showed that Alpine lakes had suffered a lowering of water levels in recent times because of deforestation. In Venezuela, Alexander von Humboldt concluded that the lake level of Lake Valencia in 1800 (the year of his visit) was lower than it had been in previous times, and that deforestation, the clearing of plains, irrigation, and the cultivation of indigo, were among the causes of the gradual drying up of the basin (Cushman, 2011). Comparable observations were made by the French rural economist, Jean-Baptiste Boussingault (1845). He returned to Lake Valencia some 25 years after Humboldt and noted that the lake was actually rising. He described this reversal to political and social upheavals following the granting of independence to the colonies of the erstwhile Spanish Empire. The freeing of slaves had led to a decline in agriculture, a reduction in the application of irrigation water, and the re-establishment of forest.

Boussingault also reported some pertinent hydrological observations that had been made on Ascension Island in the South Atlantic:

In the Island of Ascension there was an excellent spring situated at the foot of a mountain originally covered with wood; the spring became scanty and dried up after the trees which covered the mountain had been felled. The loss of the spring was rightly ascribed to the cutting down of the timber. The mountain was therefore planted anew. A few years afterwards the spring reappeared by degrees, and by and by followed with its former abundance. (Boussingault, 1845: 685)

Charles Lyell, in his Principles of Geology, one of the most influential of all scientific works, referred to the human impact and recognized that tree-felling and drainage of lakes and marshes tended 'greatly to vary the state of the habitable surface'. Overall, however, he believed that the forces exerted by people were insignificant in comparison with those exerted by nature:

If all the nations of the earth should attempt to quarry away the lava which flowed from one eruption of the Icelandic volcanoes in 1783, and the two following years, and should attempt to consign it to the deepest abysses of the ocean they might toil for thousands of years before their task was accomplished. Yet the matter borne down by the Ganges and Burrampooter, in a single year, probably very much exceeds, in weight and volume, the mass of Icelandic lava produced by that great eruption. (Lyell, 1835: 197)

Lyell somewhat modified his views in later editions of the Principles (Lyell, 1875), largely as a result of his experiences in the United States, where recent deforestation in Georgia and Alabama had produced numerous ravines of impressive size (Figure 1.1).

Figure 1.1 A newly formed ravine or gully that developed at Milledgeville, Georgia, USA, following deforestation..

Source: Lyell (1875: 338)

One of the most important physical geographers to show concern with our theme was Mary Somerville (1858) (who clearly appreciated the unexpected results that occurred as man 'dextrously avails himself of the powers of nature to subdue nature'):

A farmer sees the rook pecking a little of his grain, or digging at the roots of the springing corn, and poisons all his neighbourhood. A few years after he is surprised to find his crop destroyed by grubs. The works of the Creator are nicely balanced, and man cannot infringe his Laws with impunity. (Somerville, 1858: 493)

This is in effect a statement of one of the basic laws of ecology, much championed by Alexander von Humboldt (see Wulf, 2015): that everything is connected to everything else and that one cannot change just one thing in nature.

Considerable interest in conservation, climatic change, and extinctions arose amongst European colonialists who witnessed some of the consequences of Western-style economic development in tropical lands (Grove, 1997). However, the extent of human influence on the environment was not explored in detail and on the basis of sound data until George Perkins Marsh (Figure 1.2) published Man and Nature (1864), in which he dealt with human influence on the woods, the waters, and the sands. The following extract illustrates the breadth of his interests and the ramifying connections he identified between human actions and environmental changes:

Vast forests have disappeared from mountain spurs and ridges; the vegetable earth accumulated beneath the trees by the decay of leaves and fallen trunks, the soil of the alpine pastures which skirted and indented the woods, and the mould of the upland fields, are washed away; meadows, once fertilized by irrigation, are waste and unproductive, because the cisterns and reservoirs that supplied the ancient canals are broken, or the springs that fed them dried up; rivers famous in history and song have shrunk to humble brooklets; the willows that ornamented and protected the banks of lesser watercourses are gone, and the rivulets have ceased to exist as perennial currents, because the little water that finds its way into their old channels is evaporated by the droughts of summer, or absorbed by the parched earth, before it reaches the lowlands; the beds of the brooks have widened into broad expanses of pebbles and gravel, over which, though in the hot season passed dryshod, in winter sealike torrents thunder; the entrances of navigable streams are obstructed by sandbars, and harbours, once marts of an extensive commerce, are shoaled by the deposits of the rivers at whose mouths they lie; the elevation of the beds of estuaries, and the consequently diminished velocity of the streams which flow into them, have converted thousands of leagues of shallow sea and fertile lowland into unproductive and miasmatic morasses. (Marsh, 1965: 9)

Figure 1.2 George Perkins Marsh (1801-1882)..

Source: from the Library of Congress Prints and Photographic Division, Washington DC, http://loc.gov/pictures/resource/cwpbh.02223/ (accessed January 2018)

More than a third of the book is concerned with 'the woods'; Marsh does not touch upon important themes like the modifications of mid-latitude grasslands, and he is much concerned with Western civilization. Nevertheless, employing an eloquent style and copious footnotes, Marsh, the versatile Vermonter, stands as a landmark in the study of environment (Thomas, 1956; Lowenthal, 2000, 2013).

Marsh, however, was not totally pessimistic about the future role of humankind or entirely unimpressed by positive human achievements:

New forests have been planted; inundations of flowing streams restrained by heavy walls of masonry and other constructions; torrents compelled to aid, by depositing the slime with which they are charged, in filling up lowlands, and raising the level of morasses which their own overflows had created; ground submerged by the encroachment of the ocean, or exposed to be covered by its tides, has been rescued from its dominion by diking; swamps and even lakes have been drained, and their beds brought within the domain of agricultural industry; drifting coast dunes have been checked and made productive by plantation; sea and inland waters have been repeopled with fish, and even the sands of the Sahara have been fertilized by artesian fountains. These achievements are far more glorious than the proudest triumphs of war . . . (Marsh, 1965: 43-44)

Elisée Reclus (1873), an anarchist and one of the most prominent French geographers of his generation, was an important influence in the USA and recognized that the 'action of man may embellish the earth, but it may also disfigure it; according to the manner and social condition of...