This is unfortunately one topic where I fall into the tinfoil hat category a bit. Population is growing at an alarming rate relative to our means to support it. Without any societal changes at all, the numbers of starving people and people living in poverty increase as a byproduct of the percentages.
There is going to be a tipping point, and I'm a little afraid of what that will look like.
Imagine what it would be like if China hadn't had a one-child policy for most of that time period.