Emissions of the greenhouse gas methane from livestock are larger than previously thought, posing an additional challenge in the fight to curb global warming, scientists said Friday.
Revised calculations of methane produced per head of cattle show that global livestock emissions in 2011 were 11 percent higher than estimates based on data from the UN’s Intergovernmental Panel for Climate Change.
Periodic reports by the IPCC, drawing from thousands of scientists, help leaders take action on climate change, which has begun to wreak weather havoc around the globe.
“In many regions, livestock numbers are changing, and breeding has resulted in larger animals with higher intakes of food,” said Julie Wolf, a researcher in the US Department of Agriculture and lead author of a study in the journal Carbon Balance and Management.
“This, along with changes in livestock management, can lead to higher methane emissions.”‘
Earlier estimates, she added in a statement, were based on “out-of-date data”.
After rising slowly from 2000 to 2006, the concentration of methane in the air has climbed 10 times more quickly in the last decade, according to earlier research.
Besides natural sources such as peatland, wetlands and termites, methane from human activity — approximately two-thirds of the total is produced in two ways.
The odourless and colourless gas leaks during the production and transport of coal, oil and especially natural gas.
In roughly equal measure, it also comes from the flatulence of ruminants such as cattle and sheep, as well as the decay of organic waste, notably in landfills.