Nothing sad,it's just the circle

I was just thinking about  something.People that you love and know that go to heaven,do for a reason.Like war and catastrophe's if people lived 200 years this world would be over populated and I suspect cause multiple problems.It's selfishly sad when someone or something dies,but it makes room new life.Anything that lives must have it's time.Then the new spring up.I may be wrong,but there are to many people on this planet right now.So how is God going to solve the problem?War,asteroid,flood,biological,a disease with no cure.Any thought's about this,I would love to hear your opinion.