Extract

Problems of sustainability can arise at almost any scale of human activity that draws on natural resources or environmental amenity. In some regions minuscule numbers of hunter-gatherers are thought to have hunted Pleistocene megafauna to extinction; complex preindustrial societies have disappeared, unable to adapt to ecological changes – not least, evidence suggests, changes they themselves wrought (Burney and Flannery, 2005; Janssen and Scheffer, 2004). But modern economic development has brought with it sustainability problems of potentially far greater magnitude – a result not only of the technological capabilities at hand but of the demographic realities of much larger populations and an accelerated pace of change. A simple picture of those modern realities is seen in Figure 19.1. It charts a staggered series of population expansions in major world regions since the beginning of the industrial era, attributable to lowered mortality resulting from nutritional improvements, the spread of medical and public health services, and advances in education and income. In each of the regions population growth slows and eventually halts as fertility also drops, completing the pattern known as the demographic transition.