Environmental change

Globalization of the Environment

The story of globalization of the biophysical systems of Earth is one of local changes wrought by humans, moving through regional and intercontinental shifts to worldwide metamorphoses and coming to a truly global outreach in which human actions can alter both the upper atmosphere and the deep oceans. Essentially this trend taken over the past 10,000 years is one of coalescence, in which trade and migration have translocated flora, fauna, and environment-impacting processes. The Viking expeditions to both east and west, the [Page 495]development of the Silk Road, and the early modern European contacts with China, Japan, and Indonesia all presaged the higher volumes of translocation and coalescence under the European empires and the subsequent surges of energy-intensive development after about 1950. Yet it can be argued that there has been a countermovement of a fragmentary kind in which sequestration of natural resources and production has been implanted. The development of stratified societies once agriculture was widespread meant that some ecologies were available only to elites; the abstraction of species for specific purposes (e.g., predatory mammals for Roman circuses) disrupted ecosystems and, in modern times, the creation of National Parks and Reserves has meant the fencing-off for management purposes of tracts of land and sea separated from different areas “outside.” In a parallel social sphere, human society has become differentiated from “nature” by centuries of thought and action that emphasized human exceptionalism.

If the label “nature” is allowed for any life on the planet not affected by humans, then the notion of coalescence seems valid. Many species spread out from glacial-era refuges and coalesced with similar species to form ecosystems: Deciduous forests, for example, may have been integrations of streams of different tree species from widely separated refuges. As sea levels rose, barriers between small seas and lakes were breached and successful species colonized both sets of habitats. As related species came into proximity, hybridization took place. This type of process has a parallel in the world of physical phenomena, as the open oceans are in general of the same salinity and the upper atmosphere has the same concentrations of gases. But note that stratification occurs as well: Many ecosystems have very distinct layers of organisms. In Africa, one species of antelope lives off the plants of permanently swamped woodland and the giraffe off the top of acacia trees. Organic evolution means that speciation is a continuous, although intermittent, process and is especially noticeable in isolated places such as small islands long separated from the nearest mainland. This was the process behind the varieties of tortoise and finch that attracted Charles Darwin's attention.

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