12 / Basics of Environmental Science
This is not to say that the dividing line between mythical and rational explanations was always
clearly drawn, nor to deny that interpretations which undermined traditional beliefs sometimes
generated fierce arguments. Scientists were often engaged in attempts to reconcile the two views
and, then as now, scientific ideas could be attacked on essentially political grounds. In the years
following the French Revolution, for example, conservatives in Britain used scriptural authority to
justify the preservation of the social order. This led scientists supporting them to adapt the Neptunian
theory of Abraham Gottlob Werner (1749–1817) so that it appeared to substantiate the story of
Noah’s flood. Werner proposed that the Earth was once covered entirely by an ocean, from which
some rocks had crystallized and beneath which others had been deposited as sediment, the rocks
being exposed through the gradual and continuing retreat of the waters. This obsession with the
biblical flood continues in some English-speaking countries to the present day, from time to time
with ‘discoveries’ of the remains of the Ark, although scientists elsewhere in Europe had ceased to
take it seriously by the eighteenth century (BOWLER, 1992, pp. 129–130).
Much of the history of the environmental sciences revolves about the reconstruction of the history
of the planet since it first formed. To a considerable extent, this reconstruction was based on
interpretations of fossils, which were by no means always seen as the obvious remains of once-
living organisms.^3 Even when it became possible to use the fossils entrapped within them to arrange
rock strata in a chronological sequence controversy continued over the assignment of dates to
those strata, the mechanisms by which the rocks had assumed their present forms and distribution,
and over the total age of the Earth itself. It was in his effort to solve this puzzle that in 1650 James
Ussher (1581–1656), an Irish scholar and archbishop of Armagh, constructed what may have been
the first theoretical model. Basing his chronology on the Old Testament, he concluded the Earth
had been created in 4004 BC!
If the development of environmental science seems to have been dominated by the study of rocks
and fossils, it is perhaps because elucidating the history of the planet was a necessary first step
toward an understanding of its present condition and, in any case, the classification and distribution
of plants and animals played a major role in it. The theory of evolution by natural selection was
derived from Earth history, and Charles Darwin (1809–82) began his career as a geologist.
A unifying theme was supplied by Alexander von Humboldt (1769–1859). Mining engineer, geologist,
geophysicist, meteorologist, and geographer, Humboldt spent the years from 1799 to 1804 exploring
in tropical South America with his friend, the botanist Aimé Bonpland (1773–1858). His subsequent
accounts greatly advanced knowledge of plant geography and his five-volume Kosmos, completed
after his death, sought to demonstrate how physical, biological, and human activities combined to
regulate the environment (BOWLER, 1992, pp. 204–211). This helped establish biogeography as a
scientific discipline and applied a range of disciplines to the study of environments. Humboldt is
also credited with having shifted science generally from its rather abstract preoc-cupations in the
eighteenth century to its much greater reliance on observation and experiment characteristic of the
nineteenth and twentieth.
Biogeography also fed back into the earth sciences. Plotting the distribution of present and extinct
plants and animals played a major part in the development of the theory of continental drift by the
German climatologist Alfred Wegener (1880–1930), who sought to explain the apparent fit between
the coasts of widely separated continents, such as the west coast of Africa and east coast of South
America, by postulating that the continents were once joined and have since drifted apart. He published
this in 1915 as Die Entstehung der Kontinente und Ozeane (it did not appear in English until 1924,
as The Origin of Continents and Oceans), which led in turn to the theory of sea-floor spreading,
proposing that continental drift is driven by the expansion and contraction of the crust beneath the
ocean floor, and then, in the 1960s and 1970s, to the unifying concept of plate tectonics.