Yes, there are millions of people starving, and it is criminal that this occurs, but the point that even India produces enough food for its population actually makes the point that the humans can easily sustain themselves.
As for us poisoning ourselves through our agricultural practices, I look at it in the opposite way. It is through agricultural advancements that we are able to feed everyone (even though we don't). Farming is far more effective today than it has ever been because of how different it is now.
And from what I know, there's plenty of unfrozen fresh water to be had, it's just a matter of getting it where it's needed, and to stop using it stupidly (making deserts into lawns). To say nothing of more difficult schemes like desalinating (is that the word?) salt water.