[quote=@Didgeridont] Each of the ideas you mentioned are unsatisfactory. China's one child policy worked somewhat, however with the scale of the world we inhabit we would still end up with many country bumpkins continuing to produce more than one child. A lottery of that nature would cause too much societal strife, and might lead to unrest among the population to such an extent that they rebel against the processes which enforce the lottery. Simply euthanizing "leeches" would do little to quell the constant threat of population growth. It would disincentive people from lethargy to such an extent that they might even cause further strain on the world. And, of course, there is always the question of the global scale; it won't slow the birth rates of developing countries and is hard to enforce without incident. Constant war does too much damage to infrastructure and the environment, and can even lead to the destruction of humanity as a whole: something which is rather unwanted. Besides, war opens up too many other avenues of societal degradation (see 1984). I should have stated that by reversing population growth, I meant stopping birth rates from occurring at a replacement level, so that the next generation of humanity is much smaller than the last. [/quote] Who defines who as a 'leech'? Who is this elite to say who is and isn't allowed to exist? The general trends in population growth actually shows a general stagnation after a certain point- the fears of overpopulation are simply that, fears. The system can stabilize itself if allowed to. The issue is that there's always some complications. I just don't really think that you need that much tech for a solution. Simply a new distribution of it and even if global cooperation is impossible each country may see it crucial as to copy solutions from competitors that work. Ultimately the idea is you have a perpetual state of 'tension' induced as a means of making sure civilization doesn't become complacent. That matters more than a reliance on top-down authoritarian measures of population control that don't really solve the problem. It's the right kind of conflict you want, if you have destructive conflict you go back to the stone age- have productive conflict and you get a man on the moon. That's why I don't really advocate world government much as world governments tend to lead to global tyrants who would care more about power preservation than any abstract hope of advancing humanity, I suppose a ideological vanity project or two might happen, but I believe that a multi-polar system that doesn't collapse has the best hope of leading to a paradoxically better world. Consider the cold war and consider the constant advancements happening both in america and overseas. America won't play with biotech on humans? China will! China won't allow for new political concepts to develop? The West Will! America won't use biofuels? Brazil does! America didn't invest in a particle collider? Europe does! The need to deal with climate change will also require many solutions, thankfully more countries have leaders who believe it than don't so even if it may seem hopeless I still think that there is some chance of pulling from the brink... Even if the entropy increases may make that thought come off as foolish. Just remember that complex systems have their ways of finding a equilibrium even if it may seem like we are doomed to apocalypse at times. Technically we should've had Reagan start WW3 and wipe out the human species... Yet still we are here!