The article link :
https://legacy.carnegiescience.edu/news/war_plague_no_match_deforestation_driving_co2_buildupI believe it is possible to sustain without killing anybody if we "tax" children. Families that have more will pay more to government. It could also be called the "new citizen" care law.
Children are new citizens that receive services without paying back (as public school in most countries).
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I have found a solution along the lines. If the *
children benefits* is reduced or scale less with number of children, families will make less to save finances.
It is actually a nice article :
http://www.worldwatch.org/nine-population-strategies-stop-short-9-billionI *discovered* scientific forums and some topics discuss population control. Some solutions is education, sex education and quality of life.
With sex education, you can avoid unwanted children.
With education, you may make better life choices, trying to give more to a single kid or have more interests than *tribal sex rites*.
With quality of life, children are sometimes used to work for family or in factory. So it may make sense for some families to make many children as a free workforce.