Samantha Nutt has spent decades working on humanitarian aid in war zones. Her book, Damned Nations: Greed, Guns, Armies, and Aid, is rich in wisdom drawn from experience. But more powerful and pointed, and worth beginning and ending with, is her talk titled "The Real Harm of the Global Arms Trade."
Nutt describes child armies across the global south including eight-year-olds who have never been to school but have fought and killed using automatic weapons. Yet, she says, war can be ended despite its being "as old as existence." (I think part of the path to ending it may involve rejecting myths like the one that war is as old as existence, but never mind that.)
Nutt describes a root cause of war that the wealthy of the world could easily eliminate, because it's not found in the "human nature" of Africans but in the financial records of educated, well-off, comfortable people typically not involved in war directly.
There are 800,000,000 small arms and light weapons in use in the world, Nutt says. There are places where you can get an AK47 for $10, and where you can get an automatic weapon more easily than a glass of clean water. (Of course it would cost a tiny fraction of military spending to provide the world with clean water -- $11.3 billion per year, says the U.N.)
Nutt shows two maps of the world, one highlighting the locations of wars, the other the locations of the big weapons exporters. There's no overlap. Like alcohol for Native Americans and opium for Chinese, weapons of war are products that the United States and Europe (and Russia and China) push on targeted populations. Eighty percent of all war weapons, Nutt says, come from the five permanent members of the U.N. Security Council plus Germany.