The benefit of public transportation: Physical activity to reduce obesity and ecological footprint

Abstract

The 20th century witnessed exponential growth of the human population. A concurrent change was urbanization, with close to half of the world's population residing in urban centers at the beginning of the 21st century (McGranahan and Satterthwaite, 2003). Humans have domesticated nature with a net benefit to themselves such as enhancing food supplies, reducing exposure to predators and other dangers, and promoting commerce, often at a cost to other species (Kareiva et al., 2007). A concept, ecological footprint(EF, the amount of land required to produce the resources needed by a person annually), was first introduced in 1996 and immediately applied for cities (Wackernagel and Rees, 1996; Folke et al., 1997). The EF is comprised of resources used to meet a person's food, water, and most significantly, energy demands for housing and transportation that account for up to 90% of the EF. The concept provides a reasonable tool to demonstrate natural resource dependence of human activities to politicians and the public, although much work is needed to employ it as a cohesive analytical tool for management.