Cattle-rearing generates more global warming greenhouse gases, as measured in CO2 equivalent, than transportation, according to a new United Nations report released on Thursday.
"Livestock are one of the most significant contributors to today's most serious environmental problems," senior UN Food and Agriculture Organization (FAO) official Henning Steinfeld was quoted by the Ghana News Agency as saying on Thursday.
"Urgent action is required to remedy the situation," he said in a statement released by the UN Information Centre in Accra.
According to the report, smarter production methods, including improved animal diets to reduce enteric fermentation and consequent methane emissions, are urgently needed.
Cattle-rearing is also a major source of land and water degradation, according to the FAO report, Livestock's Long Shadow-Environmental Issues and Options, of which Steinfeld is the senior author.
"The environmental costs per unit of livestock production must be cut by one half, just to avoid the level of damage worsening beyond its present level," it warns.
When emissions from land use and land use change are included, the livestock sector accounts for 9 percent of CO2 deriving from human-related activities, but produces a much larger share of even more harmful greenhouse gases. It generates 65 percent of human-related nitrous oxide, which has 296 times the Global Warming Potential (GWP) of CO2.
The report said this accounted for respectively 37 percent of all human-induced methane (23 times as warming as CO2), which is largely produced by the digestive system of ruminants, and 64 percent of ammonia, which contributes significantly to acid rain.
"With increased prosperity, people are consuming more meat and dairy products every year," the report notes.
Global meat production is projected to more than double from 229 million tons in 1999/2001 to 465 million tons in 2050, while milk output is set to climb from 580 to 1043 million tons.