Population Control, Environment, Global Warming.....

In discussions about global warming, the environment, and climate change, the subject of population control comes up often. Many people seem to think that reducing population is the key to everything. My question is, how could that possibly be done?

Here is a graph showing the relative number of people living in different countries, from the largest number to the lesser. I think this graph is an important thing to keep in mind when discussing any of these issues. The top four countries are China, India, United States, Indonesia.

Peter