Took a great deal of research and organization None The relationship between humans and the state of the ecosystem is not only dependent upon how many people there are, but also upon what they do. When there were few people, the dominant factors controlling ecosystem state were the natural ones that have operated for millions of years. The human population has now grown so large that there are concerns that they have become a significant …showed first 75 words of 2532 total…

…showed last 75 words of 2532 total…provide a much more comprehensive and up to date treatment of the population and economic topics included here. Recent evidence (Mora et al.; SCIENCE 271:1105, 1996) indicates that the possibility of a 'greenhouse runaway' on Earth is much more remote than indicated at the end of the previous version of this document. Therefore, the former apocalyptic ending has been changed. Although the data presented points to a catastrophic conclusion, this was (perhaps) an overstatement of the case.