Overused tropes: earth is overpopulated

Of all the unused tropes I think that of the world being too full of people comes up the most. I understand the reason for it, if there are starving people there must be a shortage of food right? Same for not having houses for everyone.

The problem is that that is not how economics works, nor does every country operate every farm at the same efficiency.

North America, Central America and the Caribbean, have about 6,050,697,738 acres of land. If we moved everyone to north America we would each have almost an acre, and about double that if you included South America.

We are not starved for land, and that does not count the truly desperate and expensive things like going underground or making islands.

*Before I start please note I am not a professional farmer or doctor or anything, nor do I care to get the math exactly right, I only want to get it close enough to prove my point*

If we used aeroponics (spraying roots with nutrient rich water rather then keeping them in soil) and planted sweet potatoes (very high calorie food), we could feed something like 49,000 people per square kilometer (link, link). We could feed more if you had artificial light and stacked the farms on top of each other.

Without any artificial light you could feed the earth on farming or about a fiftieth of south America. In reality you would want more for variety, but even so I think I have made my point. If we wanted to, we could live and farm in the America’s then use the rest of the world for industry and parks.

Of course we could go even more drastic and farm algae in the ocean, (the most efficient food source we know of). This would mean we would not need to use any land for farming at all.

That is the reality. The world will not starve nor will we run out of space anytime soon. That however does not mean that everyone is well fed and housed. You can of course have a class of people who starve for economic reasons even if the food to feed them exists, or at least the production capacity exists to do so.

Now if you still want to have a world food shortage as part of your plot, then I suggest you think about why food production would be cut by several orders of magnitude and stay cut.

Sunlight would be my go to in this situation. If something is stopping enough light from getting to the surface of the earth that would mean we would have to make up the difference artificially, and that takes a lot of power. If light was that low, we would also need power for many other things, such as heating up ect. Food would become very expensive and I could believe we would only produce enough to get by and no more. The same would apply to heat.

An obvious approach might be to lower the water supply but it does not work as well as you might think. The human body does not expend water, we just hold onto it for a bit then put it back into the environment. While not 100% efficient by far, its not like electricity that is made, used and then gone.

Also water is so important for so many things that we will always give it high priority. A lack of water could change the cost of certain foods but I can’t believe it would push us to starvation. If we ever reached that point we would have much worse problems to deal with.

Honestly, where there are any number of things that could cause a temporary dip in our food production, there are not that many that would decrease it long term. Even if large amounts of soil became non-viable there are ways around that. The only other one that comes to mind is if something stopped us from using machinery, like the sun starting to emit a continuous EMP.

Overused tropes: humans are violent

As you start to read sci-fi one of the tropes that you see fairly often is that humans are a very violent people. Not to say this view is wholly unfounded of course. You can even tell some good stories with it.
Even in fiction where it is not specifically a part of the plot we are not seen as peaceful.
Don’t get me wrong, I totally understand where it comes from, our history is not exactly blood free. That however does not mean that there are no other ways to tell a story.

Everyone else is worse
This is my favorite reversal of the trope. What if we get out into the galaxy and find that we are peaceful compared to everyone else? Maybe even so much so that they can’t evolve past a certain point because of it.
Image if we find a race of aliens who are all on a hair trigger to fight to the death? They are unable to trust anyone who is not family? What if we saw that this limited their civilization. They could never have cities that go beyond a certain number of people or projects of more then a certain size.
Should we help? What if we could change them? Should we?

As a less extreme example (for a given value of extreme), we encounter other races and in every case the history is the same. They would spread out through their planet and form nations. One nation would conquer the rest, form a brutal dictatorship and rule with an iron fist. And we see that this kind of control is need to keep them together and to keep the murder rate under control. If someone tried to form a kinder government it would fail because of the realities of their psychologies.
When this culture goes out into space it would just repeat itself. Colonies would either be wholly controlled or at war with the mother world. Any aliens they encounter would be seen as a threat and diplomacy would not even be considered.
Compared to everyone else humans would seem sedate and almost insanely calm.
Now given the above, what if humans were generally at peace and had been for decades. Because we can work together well our technology and manufacturing quickly surpassed theirs.
What would you do? Could you really see them as equals? Would you try and help them? If so how? Remember we are talking about something that is biologically emergent, not a societal choice. While it might be the easy choice to go around them, what if we could not? We might have to go to war with them, not because we want to but because that is the only way they can interact with outsiders.
If we win what could we do? We could wipe them out, or we could stay and monitor them forever. We might have to do this for all of them if we wanted to stay safe from raiding parties.
How would that change us?

Our nature is necessary
I have read a few books over the years where we were seen as overly violent, but it was necessary or a useful trait. This was mostly because something needed killing. I think however that we can do better then that. One of the major driving forces of our civilization is ambition, a desire to better yourself and your group (be that family, city, or nation). If you are not willing to be confrontational then there may be no ambition. How far would we have gotten if everyone was more afraid of making waves then of anything else? After all, there is a reason that societies that value individuality tend to develop technological breakthroughs faster.

What if in the future we alter ourselves to be docile and non-violent. We might free ourselves of war at the cost of all society and technology development.