World peace is generally considered a good idea — no more wars, people living in harmony, prosperity all around. But world peace will not be good for our species, and could in fact be more detrimental than beneficial.
How detrimental, you ask? I believe world peace will lead to cannibalism.

Our progression from complete harmony to eating one another’s soft, squishy brains would take place in six neat phases.

Phase one: World Peace is Declared: Don’t worry about the specifics of why world peace is suddenly declared, that’s not the point. The point is that everyone is suddenly and miraculously cohesive. No more fighting, or killing, or nuclear threats or biologically constructed pandemics. Though it would probably be the death of the video game industry as we know it – or at least of military shooters.

Phase two: The Baby Boomer Generation: With no more prejudices, racism or hatred of any sort, people would be able to breed with whomever they like. Forget about religious constrictions. Religion would have to be abolished, since people have never been tolerant of such things. So naturally, there would be a lot of contraception in very little time. In other words — sex. Lots and lots of sex.

Phase three: Overpopulation: With all the babies being born in such a short period of time and no one killing each other off, the earth would overpopulate very quickly. We’d find ourselves packed like tins of smelly sardines, which is good if you have a hot neighbor, not so good if your neighbor is a wrinkled, 85 year-old man who likes to exercise in the nude.

Phase four: Destruction of the Natural Earth: To accommodate the huge and sudden growth of people, new cities would need to be built as well as expansions of the pre-existing ones. Say goodbye to the rainforests of South America, the grassy plains of the Midwest, the arctic tundras of Antarctica and the scorching deserts of Africa – if it’s land – we’d find a way to build on it.

Phase five: Starvation: With the earth now bursting at the seams with humans and home to nothing but infrastructure, any land for farming or raising cattle would be gone. All other animals would have to be hunted down to provide food to our greedy bellies and suddenly, before we know it — food shortage. Soon we’d be thinking things like “I’m so glad everyone is finally getting along… is it just me or is Billy’s flesh looking extra pink and tender today?”

Phase six: Cannibalism: Humans must now resort back to their natural survival instincts and eat whatever possible to stay alive, which in this case, would be other humans. Like a zombie outbreak, but without the zombies. I say start with the infants – they’d be the most tender and juicy. We could serve ‘em up at fancy restaurants, with an apple in the mouth and everything. (It’s a joke. Laugh people.)

So there you have it. World peace leads to cannibalism.