Meaty Issues

In the lead-up to climate talks at Copenhagen last year, an activist in a black-and-white cow costume held up a cardboard speech bubble with a single word: “Burp.” To those who know that methane produced by livestock is a greenhouse gas four times as potent as carbon dioxide, the message was clear. Go vegetarian, meat is killing the planet.

The U.N. Food and Agriculture Organization has estimated that livestock generate 18 percent of greenhouse gases by weight worldwide, exceeding even those spewed out from the transportation sector. In addition to methane-laced burps, livestock produce manure that makes both methane and nitrous oxide as it breaks down. Clearing for livestock range is also a serious force behind the release of carbon reserves from tropical forests. Beyond greenhouse gas emissions, cattle have long been considered an inefficient use of land and other resources, contributing to a loss of biodiversity.

Then there are the doomsday predictions for the coming century as populations in developing countries in Latin America, Asia and Africa become increasingly carnivorous. An upcoming paper in the journal Global Environmental Change by ecologist Alexander Popp at the Potsdam Institute for Climate Impact Research combines socioeconomic data and population trends to estimate that agricultural greenhouse gas emissions will almost double by 2055 if people in developing countries continue to increase the proportion of meat in their diets. So far, however, agriculture has largely escaped regulation under the Kyoto Protocol and under the now-stalled U.S. climate bill.

Despite all this, Popp and others stop short of advocating a diet of arugula for all. In the U.S. and Europe, people consume an average 78 kilograms of meat and 202 kilograms of milk per person each year. Fifty years from now, Africa and other developing countries will still have not even reached half of that percapita consumption, although total demand will be double that of developed countries. Therein lies the problem: How can we limit agricultural greenhouse gas emissions without slashing sustenance in parts of the world where soy and seafood are hardly a viable option? Certainly, Europe and the U.S. can stand to trim some of their animal-derived calories, but an equally important question is what changes need to be made to livestock production in the developing world.

Mario Herrero is a Costa Rica–born ecologist who has been based at the International Livestock Research Institute in Nairobi, Kenya, for the last 10 years and thinks deeply about the ethical and practical consequences of environmental policies. “Don’t think that a world without livestock would lead to reduced emissions,” he says. “How are you going to plow your fields without tractors? What are you going to use as your source of fertilizer?” In some regions where the growing season is less than 90 days per year, growing crops is unfeasible—so a landscape without livestock is a village without food. Limiting livestock production could also lead to increased pressures on battered fisheries or wild animal populations. Herrero suggests greenhouse gas emissions could rise if East Africa’s migrating ranchers were replaced with native impala and elephants. In fact, termites contribute 25 percent of the methane in some areas, which suggests at the very least, that native ecosystems can’t be left out of the equation.

More important, cattle are the key to African and Latin American livelihoods. In addition to generating a significant source of income, they are a symbol of wealth, a predictable food source and a four-legged insurance policy. While crops are harvested just once or twice a year, cows can be milked every morning. And with extreme weather able to knock out an entire year’s crop, keeping a few extra cows alive can be a lifesaver.

In February, Herrero argued in Science for sustainable intensification using mixed crop-livestock systems. Rather than taking the path of massive livestock and poultry operations that are common in the U.S.—and growing more common in Asia—he believes it is possible to improve meat and milk production among traditional ranchers without increasing greenhouse gas emissions. For instance, it is better to have one cow that produces 3 liters of milk each day, than three cows that produce 1.5 liters—the current average in Africa. “These animals will eat almost the same and they will produce almost the same methane, but you are multiplying your emissions by three.” Currently, residues from crops like corn and wheat are fed to cattle in developing countries. But because these crops were bred for grain production, the residues often have low energy content. By improving these “dual-purpose crops,” Herrero says it is possible to increase milk production by 50 percent.

Reducing greenhouse gases coming from emerging agricultural hot spots may also depend on changing cultural practices and bolstering financial stability. Andrew Mude, another ILRI researcher, has been working with the World Bank on a type of insurance policy for a diverse group of pastoralist ranchers. Pastoralists in Marsabit, a drought-stricken district in eastern Kenya, tend to keep unproductive animals as a security measure. With access to financial instruments, Mude believes farmers would no longer have to maintain as many extra animals, which would reduce their impact on the land and their greenhouse gas emissions.

On January 22, the institute enrolled its first farmers in a pilot program. Brenda Wandera, an agricultural economist and project manager with ILRI, says that it took a while to convince locals to embrace the methods. “We came up with insurance simulation games, and used their pastoral systems to explain these concepts,” she says. After going from village to village, Wandera and Mude got 1,979 pastoralists to start paying premiums on a total of 311 camels, 2,559 cows, and 15,826 sheep and goats. Over the next year, the researchers will monitor satellite vegetation maps, which can be used to predict livestock mortality. If more than 15 percent of the cattle are predicted to die during a season, then the insurance policy will start to pay out.

Of course, none of these developments should make Europeans or Americans complacent about their own meat consumption. Popp, who hails from southern Bavaria, says he grew up eating a lot of meat and still has a hankering for a good roast beef or beefsteak. But seeing the numbers coming out of his recent study has changed that. “Before I used to eat it once a day,” he says, “Now, I may just eat it once or twice a week.”

What’s your take on the Great Meat Debate? Send your thoughts to Momentum. We’ll publish a sampler on Momentum’s website,

BRENDAN BORRELL is a New York-based journalist who has written about science and the environment for SmithsonianScientific AmericanThe New York Times and many other publications.