A little over a decade ago the United Nations commission garnered almost worldwide political consensus on the urgent need for sustainability. Various countries and institutions started to struggle with the same problem, the question was posed--what is sustainability, and specifically, what does it mean for a particular sector, nation, or region? (Goodland, 1995). This concept of sustainability encapsulates three major sectors of global productivity: environmental, economic and social. Overlaps exist among the three, and defining each component of sustainability distinctly may help organize the action required to approach global sustainability (Goodland, 1995). Sustainability also referred to as sustainable development can therefore be defined as "Improvement in the quality of human life within the carrying capacity of supporting ecosystems ... that meets the needs of the present without compromising the ability of future generations" as stated by the Brundtland Commission (Enger, 2008). The need for sustainability arose from the recognition that the profligate, extravagant, and inequitable nature of current patterns of development, when projected into the not-too-distant future, leads to biophysical impossibilities; we cannot grow into sustainability (Goodland, 1995). The long term good health of populations depends on the continued stability and functioning of the biosphere's ecological and physical systems, often referred to as life-support systems (World Health Organization--Geneva, 2003).
Environmental sustainability seeks to sustain global life support systems indefinitely. Source capacities of the global ecosystem provide raw materials such as food, water, air and energy, while sink capacities assimilate outputs or waste. Overuse of a capacity impairs its provision of life support services (Goodland, 1995). The notion of economic sustainability was firmly embodied in the writings of J. S. Mill and T. R. Malthus who both emphasized that the environment needs to be protected from unfettered growth if we are to preserve human welfare before diminishing returns set in. Economic sustainability revolves on consuming interest, rather than capital and can be defined as the amount of goods that can be consumed during a period, while remaining well off at the end of the period (Goodland and Daly, 1996; Goodland, 2002). Social sustainability is systematic. It involves human capital that invests in education, health, and nutrition of individuals and is now accepted as a part of economic development. Ultimately, there can be no social sustainability without environmental sustainability because environmental sustainability supplies the conditions for social sustainability (Goodland, 1995).
It is all too easy to overlook this dependency, particularly at a time when human species is becoming increasingly and distanced from these (World Health Organization--Geneva, 2003) life-support, integrated, sustainable systems. As a result of human induced impacts on these systems, the human species have now placed their lives on the line. Human health plays an integral role on human existence and development, therefore an omnipresent and undeniable link exist between human health and sustainability.
The last half-century has seen momentous and accelerating changes in humankind's economic activities, political relations and social and demographic profile. Urbanism and individualism within modern Western culture has diminished people's awareness of the dependence of continued good health on the natural world (McMichael et al, 1999). However, most changes to ecosystems have been made to meet a dramatic growth in the demand for food, water, timber, fiber and fuel (Health Synthesis, n.d.). Approximately 60% of the benefits that the global ecosystem provides to support life on earth are being degraded or used unsustainably (Health Synthesis, 2005). In the 30 years after 1950 and 150 years between 1700 and 1850, more land was converted to cropland. …