Scottish-American naturalist and Sierra Club founder, John Muir (1838–1914), wrote, "When we try to pick out anything by itself, we find it hitched to everything else in the Universe." Our rapidly growing, ever more industrialized human population exists within a carefully balanced global system of physical processes that circulates chemical elements through the solid earth, hydrosphere, atmosphere, and biosphere. From agricultural land and water management, to extraction and combustion of fossil fuels, to industrial and municipal disposal of waste products, modern human activity has overprinted natural Earth cycles with synthetic ones. In many cases, these man-made alterations to the natural environment negatively impact the very Earth systems that sustain human life. Contamination of the hydrosphere and atmosphere, depletion of radiation-shielding stratospheric ozone, and anthropogenic global climate change are examples of changes induced by human environmental pollution.

Accessible, uncontaminated water is essential to all human activities, and water...