Multiple things to consider, but first, this:
There is plenty of water.
If you ignore every other thing you've ever read from me, please do not ignore this one: "plenty of water" is absolutely not true. By many measures, a lack of access to potable/drinking water is the number one threat to survival. And it's getting worse.
I'll dig up some links, but I first had this conversation with my biology professor last fall. His area of expertise is blue-green algae, which makes him an expert in certain aspects of water quality, and kind of by default, he is highly aware of issues related to water availability. Not to freak you out, but one of the projects he's involved in is about algae production as a food crop, because there are few other realistic alternatives.
Ok, moving on.
Your view of agriculture is way too narrow. Americans eat a ridiculous amount of meat compared to pretty much everyone else on Earth. The improvements I'm talking abut that have slowed the rush toward a massive starvation event are related to crops, not livestock. We've figured out how to increase yields of grain crops, and how to make them more able to resist diseases that could wipe out an entire season.
And here's the part that's likely to upset you, and I apologize in advance for that - I see these improvement as a double edged sword. Yes, it has allowed people to survive, and in some cases, even to thrive. But thriving has not been the outcome for most. Programs like "Feed my starving children" are so compassionate I find it hard to fault their intentions. But what about the bigger picture? Yes, food is being provided to people who would otherwise starve. So now what? They're alive, what's next? The recipients obviously live in an area that is not able (for whatever the reason) to provide a sustainable food supply, so their continued survival is dependent on continued food provision. When does it end? What life have they been given? Is the mere fact of existence alone enough to continue in this manner? If all that happens is the people are given enough food to make it from one delivery to the next, how is this an improvement over a prison, or a concentration camp? If they have nothing more to live for than the next food delivery, what kind of life are we offering? It just seems that keeping people alive for the sake of keeping them alive in this manner is pretty damn close to torture.
These programs are not solutions, they are band-aids. They're not meant
to be solutions either, they are meant to help people survive until real solutions can be found.
And like it or not, without controlled population growth (which is an obvious solution that's utterly impractical in application), the exportation of people to other potentially habitable planets is one that is being prepared for. If technology moves fast enough, it will be a planned departure to multiple destinations (increasing the odds of success on any by attempting to populate the most likely candidates). If not, it will be a desperate frenzy to escape whatever scenario is playing out.
And these scenarios depend on finding the political will to fund science appropriately, the political will to resist the god-botherers, other countries taking the same kinds of actions wherever possible, and surviving as a species long enough with the knowledge we gather to take any actions at all.
I blame technology for the baby boom. It's too easy to get laid online. Sex is used to promote everything.
I blame a lack of comprehensive sex ed and lack of access to dependable birth control. Your view is centered on certain lifestyles that are not the norm across the world.