Ancient Wisdom, Updated
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n Ancient Rome, the most famous statesmen proudly called themselves farmers, and many happily shared their knowledge in books for the average Joe. In one particularly well-known example, which Iowa State University historian David Hollander recalls, Cato the Elder explained how to make the most profit as a farmer: “Raise cattle.” What, he imagined someone questioning, is second best? “Raise cattle not as well.” And third? “Be a lousy cattle farmer.” These days, cattle farming may or may not be the most profitable, but from an environmental standpoint, it has some of the highest impacts. This doesn’t mean we shouldn’t do it at all, says the Institute on the Environment’s director Jonathan Foley, since some lands are particularly well-suited to raising livestock and not much else. But from a consumer standpoint, says Carnegie Mellon researcher Chris Weber, if your goal is to minimize your personal carbon footprint, one of the best ways is to eat less beef and dairy. A lot of people think you should eat locally to reduce your carbon footprint, says Weber, but if you look at the data, which he did, it doesn’t bear out. “If you were to completely localize your diet, you would reduce household emissions something like eliminating 1,000 miles a year driven in a 25 miles-per-gallon car,” he says. “But if you switch, one day a week, all your calories from red meat or dairy to vegetables, it would be like driving 1,200 miles a year less.” That’s because cows and other ruminant animals emit methane as part of their digestive process. Plus, cows eat more calories of grain to make the equivalent number of calories of meat, which means more grain has to be grown around the world. But if you love your steaks, know that, from a carbonemissions perspective, grass-fed cattle are on equal footing to grain-fed. “Although you’re cutting out emissions associated with making the grain,” says Weber, “cows that are eating grass actually belch more, so more methane is released from that. Plus they have to live longer to get to the weight needed to slaughter.”
History Lesson
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efore agriculture, people were mostly hunter-gatherers. About 10,000 years ago, that all began to change. And another 5,000 years after that, almost everyone lived in settled, agriculture-based communities. Today only a few pockets of hunter-gatherer societies remain in the world. And yet, “some studies suggest that, for the average person, after the switch to a settled agricultural lifestyle, some aspects of their life were distinctly worse,” says Iowa State’s David Hollander. “The average hunter-gatherer had a much broader, diverse diet than someone in a settled agricultural environment, and general health seems to have declined.” The whys of societal change are always multifaceted. “But it seems one thing that’s going on is that people, given the choice, would rather have the more secure food sources than the better diet,” says Hollander. And if you define the success of a species by its proliferation, agriculture seems to have been a pretty good idea. By one estimate of the world’s population, in 130,000 B.C., there were about 100,000 people. In 10,000 B.C., there were about 7 million. Then agriculture was invented, and by 81 A.D., there were about 300 million people in the world. Perhaps agriculture wasn’t the reason for the rapid increase in population growth. It could be the other way around: Agriculture was invented because there were more people in the world. Either way you look at it, the average ancient farmer needed a lot more land to produce the same amount of food as the modern farmer—and the average huntergatherer needed even more land than that. Today, with 6 billion people and rising, we should probably be glad our ancient ancestors picked up the plows.
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