ABSTRACT
Environmental issues are not new phenomena. People have always interacted with the natural world and these interactions have always thrown up challenges to human societies. Mistakes have been made and solutions o en found to problems encountered or created. However, as human society has become more complex, as populations have increased, so the range and scale of environmental issues have multiplied. Although there are still many sizeable portions of the Earth that show little obvious evidence of human impact (e.g. many hyper-arid deserts, the deep oceans, parts of the polar regions and some of the tropical rain forests), there is nowhere that is not aff ected to some extent by changes in the chemical make-up of the atmosphere and associated changes in climate and pollution levels (Figure 22.1). Likewise, the nature of relatively unaff ected parts of the planet also has an impact on those regions that are directly used by human populations, through their eff ects on global climate and biogeochemical cycles.
