overpopulation. biggest problem of all. with climate change and turmoil, massive numbers of people will have to be moved from place to place..good luck with that. first of all make sure that men and women are allowed to choose their family size, which probably won't be ten kids. get any religions to quit making people suffer in poverty when their lives could be bettered. unless there is wwiii, which could happen..we have many ingredients to turn things around..birth control, internet, charity water, free energy coming..smarter construction..better education, cell phone throughout populations bring improved agriculture and medicine...robots for most dangerous work...it all can be improved if populations don't exceed resources...