Meat Production and Climate Change
In the News
January 29, 2014
Greenhouse gas emissions from meat production are significant and need to be reduced, according to a recent report published in the January 2014 issue of Nature Climate Change, a scientific journal. William Ripple, professor at Oregon State University, and co-authors from Scotland, Austria, Australia and the United States reached their conclusions on the basis of a synthesis of current scientific knowledge on greenhouse gases, climate change and food and environmental issues. The report looked at the detrimental effects of meat production on climate change from non-CO2 greenhouse gases emissions, which contribute to about a third of total emissions. Methane (CH4) is the most abundant of these non-CO2 gases.
While there are several sources of methane emissions, including the fossil fuel industry, landfills, biomass burning and rice production, this report focuses on emissions from ruminants. Ruminants are animals like cattle, sheep, goats and buffalo that eat plants and digest them through a process called enteric fermentation in a multi-chambered stomach. This process produces methane gas as a by-product. By comparison, non-ruminants, like pigs and poultry, have a single-chambered stomach for digestion. Therefore, their methane emissions are much lower.
There are 3.6 billion domestic ruminants on Earth in 2011 – 1.4 billion of those are cattle. Each year, the meat industry adds, on average, 25 million domestic ruminants to the planet. Why? Because as developing countries become wealthier, the demand for and production of meat increases, says study lead author Dr. William Ripple. Worldwide, livestock accounts for about 14.5% of human-caused greenhouse gas emissions, with cattle contributing the most. Ruminants around the globe contribute 11.6% of all greenhouse gas emissions. Cattle contribute 9.4%.
The majority (70%) of agricultural land globally is dedicated to livestock, and feed-crop productions take up 33% of total arable land. Not only are feed crops in direct competition with producing food for human consumption, but they also disrupt climate mitigation. In addition, the expansion of land areas for feed crops has led to deforestation (a major source of greenhouse gas emissions from livestock production) in many tropical areas, devastating native forests. Also, with over 800 million people chronically hungry, the authors state that the use of highly productive croplands to produce animal feed is actually questionable on moral grounds, as it exhausts the world’s food supply.
Lowering ruminant numbers would have many benefits worldwide, the authors report, including regrowth of forests, improving soil organic carbon, improving water quality and availability, and repairing natural biodiversity. Furthermore, if consumers reduce their meat intake, they can benefit from reducing their rates of obesity, diabetes, some common cancers and heart disease.
Interestingly, the livestock sector has been exempt from most policies that strive to reduce climate change. And with annual meat production growing rapidly worldwide, this greenhouse gas footprint will also continue to grow. As it stands now, this footprint from cattle is about 19-48 times higher than that of high-protein foods obtained from plants. Pigs and poultry have a smaller footprint, but it is still 3-10 times greater than high-protein plant foods.
“The lack of focus on the livestock sector for mitigating climate change may be due to the strong emphasis to reduce carbon emissions from fossil fuel combustion. There also seems to be a lack of awareness that the livestock sector is responsible for a significant proportion of greenhouse gas emissions,” says Ripple.
Policies are needed to both reduce meat consumption as well as improve agricultural production efficiencies. A more comprehensive approach is needed to alleviate the effects of climate change from meat production and it needs to be done soon, says Ripple, while there still time to prevent catastrophic climate change.
“Once citizens and policy makers become aware of the significance of livestock’s contribution to climate change, I would expect to see some policies implemented within nations and more negotiations on this at international climate meetings,” he adds.