The Science of Sustainability
Common sense tells us that air, water, food, and shelter are fundamental to the survival of humans and businesses. However, the pathway to healthily integrating the two remains a challenge. Read this chapter to explore the important interrelationships between the environment, society, and economics and their importance to sustainable business. What are the merits of both views of economics with limits versus no limits to growth? How do businesses and individuals threaten ecosystems and the environment? What roles can businesses play in addressing environmental challenges as well as the limitations?
2.3 Human Activity Impacts on Ecosystems
IPAT Relationship
Human population growth is a factor in human ecosystem impact. From 0 AD to the present, global population has increased from three hundred million to seven billion. While population growth was once considered to be one of the leading drivers of human impacts on ecosystems, it does not adequately explain all the impacts that come from human activities. One concept that is useful in understanding the multiple factors that interact to impact environmental quality is the IPAT equation. The equation was developed in the early 1970s by scientists John Holdren and Paul Ehrlich to explain the human factors that create environmental impact.
Impact (I) was expressed as the product of population (P), affluence (A), and technology (T). This formula doesn't quantify actual impacts, but is meant to state relationships. Also, P, A, and T are not independent variables but are interdependent. It does not show a simple multiplicative relationship among the main factors; research has shown that a doubling of population, for example, does not necessarily lead to a doubling of impact. Affluence is related to consumption where more affluent societies are able to consume more resources than less affluent societies can. Technology is a more complex factor as it can provide the means to extract greater quantities of resources but also can be used to limit consumption of resources.
The IPAT equation does not identify sustainable limits but does assist in increasing understanding of the general factors that increase or decrease environmental impact. By highlighting the interplay among a variety of factors in creating an impact, the IPAT equation demonstrates that there are multiple ways of reducing undesirable effects.