Human Population Issues

Human Impact Model I = PATS Models are simplified representations of complex systems. Models can be precise or conceptual. This model is conceptual, to guide your thinking about human impact and sustainability.

I = PATS I is the impact of humans on the environment P is the population of humans in the affected environment A is the affluence level of the human population T is the technologies that the human population is using S is the sensitivity of the environment to human disturbance

Population Population growth is the root of many environmental problems, although it is NOT the only root. There is a carrying capacity for humans based on environmental limitations Our technology has increased human carrying capacity, but there have been other consequences to these increases.

Human carrying capacity

Affluence Affluence means quality of life. In terms of environmental impact it is often proportional to the amount of natural resources that an individual (or country) uses. Higher affluence often correlates with higher environmental impact The gap between rich and poor societies is a cause of social and environmental stress

Consumption leads to waste

Rich vs. poor

Ecological Footprints

Technology - what do you think? How does technology make human impact greater? How can technology reduce human impact?

Sensitivity Sensitive environments are more affected by a given amount of human activity Sensitive environments include deserts, grasslands, and tundras Luckily, humans populations are not very dense in these types of environments

Another representation… In Industrial Ecology, IPATS is couched as the “ Master Equation: ” In this form we can see the opportunity for improvement lies in the technology term, environmental impact per unit GDP