There may be over 10 billion of us by 2100
Climate change may be the existential threat, but underlying this is, of course, population size. And this is a problem that never seems to go away. There are of course two ways, broadly speaking, to limit population growth aside from draconian policies governing reproduction (such as China's One Child policy). One is sometimes called the demographic transition. This is when a combination of factors including so-called modernization which may involve increase quality of health care in combination with increased social equality lead to lower birth rates.
Source: scienceblogs.com
