Despite the many possible technological and political solutions to global warming, one highly effective way to reduce carbon emissions is pretty straightforward: stop procreating.
This seems, at first, like one of those painfully self-evident scientific conclusions. Fewer humans generate less greenhouse gases, so global warming slows. This study, published in the Proceedings of the National Academy of Sciences and performed by the National Center for Atmospheric Research (NCAR), the International Institute for Applied Systems Analysis (IIASA) and the National Oceanographic and Atmospheric Administration (NOAA), is interesting because it attempts to quantify population effects on global warming projections.
The researchers drew from a number of data sources and demographic projections of potential population "growth paths." Then they created global warming scenarios using a computer model called the Population-Environment-Technology model. Their projections were detailed enough to consider household type, urban versus rural populations, and population aging.
Some of their findings were hopeful. If population growth follows a slower growth path, the slowdown itself could account for up to 29 percent of the emissions reductions thought to be necessary to prevent harmful climate change. Aging populations can reduce emissions as well, since they tend to fuel less economic growth and industrial output – some industrialized nations could see a 20 percent drop in emissions just by getting older.
Brian O'Neill, lead author of the paper and a scientist at NCAR, said, "If global population growth slows down, it is not going to solve the climate problem, but it can make a contribution, especially in the long term."
Unfortunately, a subtle shift in demographics can exacerbate the problem. If population growth favors urban areas, it could result in a 25 percent increase in greenhouse emissions. Growth in developing countries, which use more energy per capita than industrialized nations, might also throw off the balance.
There are plenty of high-tech potential solutions to greenhouse emissions, from carbon sequestration to electric cars. This study shows that we can put a huge dent in the problem with technology that's 50 years old (birth control pills) or even a few centuries old (condoms).