dilluns, 15 de desembre de 2014

Thousands of years to recover

In the standard account of human history, agriculture represents the ur-breakthrough. The domestication of plants and animals allowed people for the first time to build up surpluses of food. This, in turn, allowed them to think about something besides feeding themselves. They became merchants and priests and artisans and bookkeepers. They built villages, towns, and cities. Every subsequent innovation—metallurgy, writing, mathematics, science, and even paleo web sites—could be said to owe its origin to those first farmers scratching with sticks in the dirt.
Agro-revisionists also regard the Neolithic Revolution as a critical event. They, too, believe that without it modern society wouldn’t exist. What they’re not so sure about is whether it was a good idea.
“The adoption of agriculture, supposedly our most decisive step toward a better life, was in many ways a catastrophe from which we have never recovered” is Jared Diamond’s dour assessment, offered in an essay titled “The Worst Mistake in the History of the Human Race.”
Like Stone Age hunter-gatherers, early farmers left little behind—just some burnt grain, mud foundations, and their own bones. But that’s enough to reveal how punishing the transition to agriculture was. According to a study of human remains from China and Japan, the height of the average person declined by more than three inches during the millennia in which rice cultivation intensified. According to another study, of bones from Mesoamerica, women’s heights dropped by three inches and men’s by two inches as farming spread. A recent survey of more than twenty studies on this subject, published in the journal Economics and Human Biology, found that the adoption of agriculture “was observed to decrease stature in populations from across the entire globe,” including in Europe, the Middle East, Asia, and South America.
Early farmers were not just shorter than hunter-gatherers; they were also more sickly. They had worse teeth—one analysis from the Near East suggests that the incidence of cavities jumped sixfold as people started relying on grain—and they suffered from increased rates of anemia and infectious disease. Many now familiar infections—measles, for instance—require high population densities to persist; thus, it wasn’t until people established towns and cities that such “crowd epidemic diseases” could flourish. And, by living in close proximity to their equally crowded farm animals, early agriculturalists helped to bring into being a whole set of diseases that jumped from livestock to people.
“The adoption of agriculture,” Diamond notes in his most recent book, “The World Until Yesterday,” provided “ideal conditions for the rapid transmission of microbes.” According to Daniel E. Lieberman, a professor of evolutionary biology at Harvard and the author of “The Story of the Human Body,” “farming ushered in an era of epidemics, including tuberculosis, leprosy, syphilis, plague, smallpox and influenza.”
It took thousands of years for human bodies to recover; Lieberman reports that “it wasn’t until the twentieth century that Europeans were the same height as cavemen.” And, almost as soon as the stature gap closed, new problems arose. People began to grow not just taller but also wider.
Elisabeth Kolbert. Stone soup. The New Yorker.

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