Overpopulation - ALL other problems stem from this problem. You can mention any other problem, and it is linked to overpopulation. Environment/climate change - too many people chopping down trees, polluting, using resources, destroying habitat, killing animals etc. A few people do it no problem, but Billions do it - then it's a big problem. War - the more people we have, the more fighting over resources etc. more likely to go to war if we are closer together in cramped conditions etc, and the bigger the wars become and the more frequent - overpulation is the key facter! Extremism (not just religion, but all extremism) - again it's not a problem if a few people are that way, but when you have millions or billions of people with such views, THEN it is a big problem. Understanding - I don't care if a few people don't understand me, especially if they live a world away and we never meet, BUT, when 7 billion people have to all understand eachother, well that's just crazy impossible! Poor education - again, too many people to educate properly, so the elite get the best and millions have none - clearly [ceteris paribus- all else being equal] a class with 5 students is better than a class with 100. Global meltdown, deficits etc. - too many people spending too much money, and too few people with the knowledge to do anything about it, given the sheer number of people that need to be satisfied in all their diversity, as well as a lack of real accountability
Is there a god or gods maybe? I honestly don't have an answer for everyone, but I do have unending questions - should I stop asking those questions? Did god / gods create evolution? Where did he/she/they come from? Should women be locked out of sight - only to rule in the home? Should we respect all religions, or is it right to kill those who don't agree with our brand? How about respecting atheists' points of view - to them it might be offensive not to be able to question, to speak out freely, in criticism of religion. Is religion just a fashion - one day we should stone homosexuals to death, the next we should welcome them into marital society - regardless of the original 'word of god' as laid out in the bible, for example?
Habitat destruction, species extinctions, pollution, war, and inequality, poor education, starvation, resource wars, extremism etc. - all from us mere 7 billion humans. We certainly do exacerbate the situation, despite geological evidence to show the trends on a universally large scale [approaching the sun, receding from the sun]. What will future generations say of us? Will there even be future generations? We chop down the Amazon, and ALL other forests - replacing them with our own monocultures, like cutting out our lungs and depleting the Earth's natural medicine store. Our industry accelerates the warming of the climate, melts the ice caps, and robs other species of life itself. It's all too depressing! Can technology help to save us? I hope so, but it is a titanic struggle for our own survival.
Everything is dumbed down, lower and lower from generation to generation, and there is a lack of respect for intellect and education, replaced by an infatuation with [often meaningless] information. The news, for example [whether USA, UK, or even China] is just infotainment, soundbites of rolling 24 hour 'news' without any real substance. People are thus like mushrooms - kept in the dark and fed on muck - like herded animals, unquestioning and brutal [just the way our dear leaders want us!]
Inequality, poverty, lack of education, war - leads to people wanting and having more children... back to the major problem facing humanity today - OVERPOPULATION!