That eating meat can contribute to climate change is a sore subject for many. Much research has pointed out that livestock production is a significant source of greenhouse gases. Most recently, a study detailed how a worldwide shift to a less meat-based diet could slash greenhouse gas emissions related to the food system by more than half. But changing meat-eating cultures and customs on a massive scale is not going to be feasible any time soon.
Now a new study points out that the livestock industry can cut emissions without a drop in productivity. It showed that improved feeding practices and better land and manure management could have a big effect on greenhouse gas emissions. Researchers at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia published these findings in the journal Nature Climate Change.
Mario Herrero and his colleagues estimated that rearing livestock—cattle, sheep, goats, pigs and chickens—contributed 6.1–8.2 billion tons of greenhouse gases including carbon dioxide, methane, and nitrous oxide to the atmosphere each year. This represents about 18 percent of global emissions.
One of the biggest sources of those emissions is the approximately 1.7–2.9 billion tons (in carbon dioxide equivalent) of methane that is released by livestock during digestion. Another 1.4–2.2 billion tons (in carbon dioxide equivalent) of nitrous oxide come from producing feed for the animals. Finally, around 1.7 billion tons of carbon dioxide emissions come from land use changes such as clearing land for pasture.
While the developed world might have higher total emissions, the researchers say in the study, the emissions intensity—i.e. the amount of greenhouse gas that goes into producing one kilogram of protein—is lower than that of the developing world because of better feeds and management practices that have already been adopted.
The researchers found that some of the biggest global greenhouse gas reductions (over 1 billion tons) could come from reducing digestion-related emissions by using chemical additives in feed; mixing in energy-dense foods such as cereal grains; and having fewer, better-fed animals. Managing grazing land better—for instance by avoiding overgrazing or planting legumes in pastures—could cut up to 1 billion tons of carbon emissions. Other practices that could impact emissions include better manure treatment and storage and reducing land use by having smaller, more productive herds and improving feed crop yields.
The tricky part will be balancing the adoption of these greenhouse gas reducing practices with negative impacts on livelihood and economic activities, especially in the developing world.
“We need to increase the adoption of these different strategies by making sure that we have the right incentives,” Herrero said in a press release. “If appropriately managed with the right regulatory framework, these practices can also achieve improved environmental health over and above the greenhouse gas benefits delivered, for example through improved ground cover and soil carbon.”
