A new climate change study issued by an Oregon State University professor and others concludes the best way to reduce methane gas emissions is to reduce cattle, sheep and other ruminant herds worldwide.
The conclusion isn’t likely to be favored by industry groups, but OSU forestry Professor William Ripple and co-authors said herd reduction should be considered an antidote to climate change along with cutting back on fossil fuel use.
“Because the Earth’s climate may be near a tipping point to major climate change, multiple approaches are needed for mitigation,” Ripple said in an OSU news release.
The Oregon Cattlemen’s Association dismissed the recommendation to reduce herds.
Methane produced from “enteric fermentation” by livestock amounts to only about 2 percent of greenhouse gas emissions, association communications officer Lauren Montgomery said in an email. She said other sources, including wildfires, produce much more.
She said such studies have not taken into account what “substitute” greenhouse gases might be produced if livestock are reduced or even eliminated. The association believes assessments of greenhouse gas impacts should include an accounting of energy used per gas unit produced.
“The idea that a certain percentage of GHG would be eliminated by simply eliminating livestock is unrealistic,” Montgomery said.
Carbon dioxide, produced by burning fossil fuels, is the most common greenhouse gas. But scientists say methane, which cattle, sheep and goats produce as part of the digestive process, is particularly adept at trapping heat in the atmosphere.
The research paper, “Ruminants, Climate Change, and Climate Policy,” was prepared by Ripple and co-authors in Scotland, Austria, Australia and the United States.
The researchers concluded that greenhouse gas emissions from cattle and sheep are 19 to 48 times higher per pounds of food produced than the gas emitted in the production of plant protein foods such as beans, grains or soy.
The authors said the number of ruminant livestock has increased worldwide by 50 percent in the past 50 years, to about 3.6 billion animals. About 25 percent of the earth’s land area is dedicated to grazing, and a third of all arable land is used to grow food for livestock, according to the report. Reducing the number of cattle and sheep on the planet, and thereby reducing methane gas emissions, is a faster way to impact climate change than reducing carbon dioxide alone, the report concluded.