Potatoes & guano. Also, airline security.

Charles Mann wrote the wonderful book 1491, a summary of research on the Americas before Columbus, as well as 1493 (which I haven't read yet), a sequel of sorts that takes on the post-Columbus exchange of ideas, tools, plants, and germs. He's also written an article titled "How the Potato Changed the World" (which I imagine covers some of the same material as 1493) in the latest Smithsonian. One of the most arresting sections of the potato article is actually about a forgotten commodity. Today we take nitrogen fixation for granted, but its industrial perfection enabled a massive increase in world agricultural output, and more darkly the use of chemical weapons during the First World War. But prior to all that one of the best source of nitrogen was guano, or bat and bird dung:

In 1840, the organic chemist Justus von Liebig published a pioneering treatise that explained how plants depend on nitrogen. Along the way, he extolled guano as an excellent source of it. Sophisticated farmers, many of them big landowners, raced to buy the stuff. Their yields doubled, even tripled. Fertility in a bag! Prosperity that could be bought in a store!

Guano mania took hold. In 40 years, Peru exported about 13 million tons of it, the great majority dug under ghastly working conditions by slaves from China. Journalists decried the exploitation, but the public’s outrage instead was largely focused on Peru’s guano monopoly. The British Farmer’s Magazine laid out the problem in 1854: “We do not get anything like the quantity we require; we want a great deal more; but at the same time, we want it at a lower price.” If Peru insisted on getting a lot of money for a valuable product, the only solution was invasion. Seize the guano islands! Spurred by public fury, the U.S. Congress passed the Guano Islands Act in 1856, authorizing Americans to seize any guano deposits they discovered. Over the next half-century, U.S. merchants claimed 94 islands, cays, coral heads and atolls.

Read the rest of the Mann potato history article here. A related academic paper is Nathan Nunn and Nancy Qian's "The Columbian Exchange: A History of Disease, Food, and Ideas" (ungated PDF).

And while the idea of this blog post was simmering in my head I came across another piece by Charles Mann in Vanity Fair, this time on air travel security and how so much of it is theater to reassure the public. It's called "Smoke Screening":

Remember the fake boarding pass that was in Schneier’s hand? Actually, it was mine. I had flown to meet [TSA critic] Schneier at Reagan National Airport because I wanted to view the security there through his eyes. He landed on a Delta flight in the next terminal over. To reach him, I would have to pass through security. The day before, I had downloaded an image of a boarding pass from the Delta Web site, copied and pasted the letters with Photoshop, and printed the results with a laser printer. I am not a photo-doctoring expert, so the work took me nearly an hour. The T.S.A. agent waved me through without a word. A few minutes later, Schneier deplaned,compact and lithe, in a purple shirt and with a floppy cap drooping over a graying ponytail.

The boarding-pass problem is hardly the only problem with the checkpoints. Taking off your shoes is next to useless. “It’s like saying, Last time the terrorists wore red shirts, so now we’re going to ban red shirts,” Schneier says. If the T.S.A. focuses on shoes, terrorists will put their explosives elsewhere. “Focusing on specific threats like shoe bombs or snow-globe bombs simply induces the bad guys to do something else. You end up spending a lot on the screening and you haven’t reduced the total threat.”