Socially speaking, going by the past 5,000 years of human culture, if women are allowed to control their own bodies and have access to contraception, without any outside influence population will become rather static at replacement values of two children per woman.
As soon as governments, religions and patriarchal societies prevent women from taking care of their family planning, over-population occurs.
So, put the blame where it belongs, humans don't naturally over-populate, that is a modern result of outside influences affecting the natural tendency of women to balance their lives.
If you really want to do something about it, give the women of the world choices, they will without any other influence handle this problem, until that happens forget it, ain't going to happen and you get massive slums growing at 400-600% a year in urban areas all over the world as we see right now.
As for global heating, all of our machines and power plants waste twice the amount of energy into heating the universe as they deliver as useful work.
This will overheat the planet regardless of whether our petty arguments about greenhouse emissions result in lower emissions or not.
So all you smart talkers, the problem to solve for you is to take the waste heat from burning gas and put it to useful work.
Simple, huh?
Maybe they don't talk thermodynamics on Fox News, we've killed over 750,000 people in Iraq already and still don't have it under control because our enemy is really ourselves and the thinking that you can dominate people as a strategy. Humans have proven the despots, totalitarians, authoritarians from history to be vulnerable to defeat in the end.
Vietnam.
Great war for America, we got another one going right now that'll end about the same. Then, once we're gone the people will pick up the pieces of their country and slowly move toward their culture's center, not the oppressor's.
Meanwhile the real affect of the expense of war is why the American economy is soooooooooo strong, soooooooooo healthy, it's why the world is buying dollars, they are worth sooooooooooo much.
But, that's too obvious to think about ... sorry, didn't mean to pop a global pimp for profit.