Population growth and global change

Abstract

There has been enormous growth in the human population, from 1 to 10 million about 10,000 years ago to more than 7 billion in 2013. There have also been huge increases in the populations of species living in close association with humans. Just as important, history has witnessed a great intensification of per-capita environmental effects related to the use of natural resources, the generation of wastes, and damage caused to biodiversity. The multiplicative consequences of population size and per-capita effects are captured by indicators such as ecological footprints, thereby allowing the notion of overpopulation to be applicable to both less-developed and wealthier countries. Because of its enormous size, the global population is at risk of suffering a large and rapid “crash” as a consequence of environmental damage that has decreased carrying capacity for the human economy, or by a global pandemic caused by an emergent disease. Human overpopulation and the environmental and ecological damages that it causes provide the essential context for the study of all anthropogenic global changes.