Here's why. A whopping 30 percent of the globe's land area already is used, one way or another, to raise livestock. The key is to prevent that area from expanding as countries like China, India and Brazil ramp up their meat production. Converting more land for animals can create a lot of new emissions. For example, significant emissions have come from turning forests or savannahs in Brazil into grazing areas and into fields devoted to growing crops for feed.
But according to the researchers, a lot of animals in the poorest corners of the world still eat only grass. This way of producing meat isn't a very efficient use of land, and in the long run, these animals actually emit more greenhouse gases, per pound of meat produced, than an animal raised in an industrial facility on grain.
"If we're able to develop policies to become more efficient producers of these products, we can continue to meet demand while reducing emissions," Rich Conant, an ecosystem ecologist at the Natural Resource Ecology Laboratory at Colorado State University and a co-author of the study, tells The Salt. "We already know there are lots of things producers can do on the farm, and there's a lot of research going on how they can more effectively manage the herd, to how they can get more meat from the animals, to how they manage the waste."
In fact, the researchers argue that a global tax on meat production for its greenhouse emissions would be misguided. It could make meat too expensive for the poorest people who really need it for nutrition. Instead, the researchers advocate policies that try to limit land-use change by making farmers more productive.
So what does this mean for consumers who want to buy the most environmentally sound meat? According to Conant, over the next couple of years we should get a much better idea of how to compare the efficiency of livestock producers and choose accordingly.
Mario Herrero, the chief research scientist at Australia's national science agency, the CSIRO, and another of the study's authors, says Brazil has started a certification scheme for meat coming from the Amazon to ensure that it does not come from deforested land. "This seems to be working," Herrero tells us in an email.
"I think there should be tax breaks or incentives (payments for ecosystems services) for farmers to use their land in ways that produce food sustainably," he adds. "These mechanisms are more efficient than taxing the products we should consume less of."
And Doug Boucher, who directs climate research and analysis at the Union of Concerned Scientists, says consumers in rich countries where overconsumption of red meat in particular is linked to health epidemics like diabetes and cancer still need to think about cutting back.
"We are already consuming at a level that's harmful to us, and so we might as well shift over to chicken and pork, eggs and milk because they also have much lower greenhouse gas emissions than beef," says Boucher. His paper, published in Nature Climate Change in December, showed that ruminant livestock — including sheep, goats, buffaloes and, most important, cattle — produce significantly more greenhouse gas emissions than poultry, pork or plants.
"It's not a matter of giving up meat. It's a matter of shifting to other kinds that have less climate impacts," Boucher says.
Copyright 2014 NPR.