Death by warfare is on the decline, poverty globally is decreasing, affluence is increasing, technology is rapidly improving, communications are knitting together all cultures and regions of the world in ways we can't fully appreciate even while it's happening. Compared to even two decades ago there are millions upon millions of people who are no longer in poverty. There are countries who have become part of the developed, 1st world. And there are more countries on the way. "Developing" isn't just a euphemism for 3rd world shit-hole, a lot of countries are on their way towards the same level of affluence and development as the G8/G20.
Certainly there are a lot of problems in the world, some of them unprecedented problems. But there's little cause to bemoan the increasing population of the Earth. Human civilization is becoming more and more capable of dealing with problems like poverty, famine, environmental degradation, and even global climate change, even as it adds more and more members to its family.