Forget the “war on coal.” The next battle in the fight against climate change may be a war on cows, sheep, and goats.
In the gallery of global warming villains, big industry tends to grab greatest attention. But that’s forgetting the part played by innocent ruminant animals. There are now 3.6 billion such creatures roaming the planet, which is 50% more than 50 years ago, and collectively they account for about 15% of all human-related greenhouse gas emissions, according to the United Nations.
A new paper in the journal Nature Climate Change argues that addressing climate change requires focusing on agriculture’s impact. The authors even recommend ways to reduce ruminant numbers–for example, through taxes on meat or a system for capping and trading emissions related to livestock.
Cows and sheep are important because there are so many of them, and because the methane gas they belch and fart is up to 30 times more powerful than carbon dioxide. “We clearly need to reduce the burning of fossil fuels to cut CO2 emissions. But that addresses only part of the problem. We also need to reduce non-CO2 greenhouse gases to lessen the likelihood of us crossing this climatic threshold,” says William Ripple, a professor at Oregon State University, and a co-author of the study.
Reducing ruminant numbers would also cut the amount of land currently given over grazing–about a quarter of the world’s total. In addition, about a third of arable land goes toward producing feed for cows, goats, and sheep. Emissions from cattle and sheep are 19 to 48 times higher per pound of food produced than plant-based products.
The authors say new feeds (which reduce emissions) could also increase efficiency (as advocated here). But cutting animal populations would have a bigger effect. “Cutting the number of ruminant livestock could have additional benefits for food security, human health, and environmental conservation involving water quality, wildlife habitat, and biodiversity,” says Pete Smith of the University of Aberdeen, another of the authors.