Foreword

The economic development that was initiated by the Industrial Revolution has been self-consciously intensive in the use of natural resources. The pace has not slowed. Since the end of the Second World War, even as world population and average income per person have grown at unprecedented rates, humanity’s reliance on natural resources in large measure has increased correspondingly. During the twentieth century world population grew by a factor of four (to more than six billion) and world output by fourteen, industrial output increased by a multiple of forty, and the use of energy by sixteen. Methane-producing cattle population grew in pace with human population, fish catch increased by a multiple of thirty-five, and carbon and sulfur dioxide emissions rose by a factor exceeding ten. Vitousek et al. (1986) estimated that some 40 percent of the 45–60 billion metric tons of carbon that was then being harnessed annually by terrestrial photosynthesis (net primary production of the biosphere) was being appropriated for human use.

In this century the pace has accelerated. The release of nitrogen to the terrestrial environment from the use of fertilizers, fossil fuels, and leguminous crops now well exceeds that from all natural sources combined. Carbon concentration in the atmosphere is currently rising at a rate of 1 part per million a year, the concentration having just passed 400 parts per million, a level not reached since more than two million years ago. The scale of the human enterprise is so influencing global environmental change now, that as Ehrlich and Ehrlich (2008) documented, we should recognize humankind as earth’s dominant species. Humanity would appear to have ushered in a new geological epoch in which our activities are influencing not only local landscapes but also the global processes driving the earth system. Appropriately enough, the present era has recently been christened Anthropocene (Steffen et al. 2011).