We tend to treat population growth and environmental degradation as though it were a one-way causal street, namely population growth causes environmental degradation. However, there is no lasting empirical evidence that has affirmed this claim.
However, there is ample evidence–to be scientifically correct, not causative evidence but ample associative evidence–that environmental degradation negatively impacts population growth. One example is endocrine-disrupting compounds (EDCs) that interfere with the sexual development of animals. A study just published by the University of Ottawa reports on the impacts of exposure to high levels of one such EDC, hexachlorobenzenes (HCBs), on the sex selection of children. The study tracked over time the number of boys and girls born in a native community in Sarnia, Ontario. The Aamjiwnaang community live next to the Sarina-Lambert Chemical Valley, a complex of petrochemical, polymer, and chemical industrial plants.
The authors tracked the sex ratio from 1984 to 2003. From 1984 to 1992, the ratio of boys to girls was about 1. But something happened in the mid-1990s and the ratio of boys to girls declined. These were not minor differences in the sex ratio: from 1999 to 2003, half as many boys as girls were born to members of the Aamjiwnaang community. The authors are not sure why the rate declined when it did–they do not have longitudinal data on environmental quality. However, a 1996 soil study found high concentrations of both inorganic and organic contaminants. Among the organics, high levels of HCBs were found in the soil.
If you’re interested, the full text of the study is available here. It’s an easy, albeit alarming, read. In addition to effects on human population, the study also reviews the endocrine disruption in local wildlife in the region.
Many EDCs are essential to computer production. See related post on the impacts of brominated flame retardants.