And, worldwide, ruminant livestock produce 28% of global methane emissions from human-related activities.
Globally, ruminant livestock produce about 80 million metric tons of methane annually, accounting for about 28% of global methane emissions from human-related activities. An adult cow may be a very small source by itself, emitting only 80-110 kgs of methane, but with about 100 million cattle in the U.S. and 1.2 billion large ruminants in the world, ruminants are one of the largest methane sources. In the U.S., cattle emit about 5.5 million metric tons of methane per year into the atmosphere, accounting for 20% of U.S. methane emissions. How much methane is produced by livestock?
So implementing methods to reduce anthropogenic methane from cow-burbs, as well as from landfills and natural gas & petroleum systems, makes good sense, since they all contribute to non-CO2 GHGs & AGW.
But none of that changes the scientific facts that anthropogenic CO2 is principally caused by fossil fuel emissions and is responsible for approx 70% of AGW.
Approximately 30% of the human-induced greenhouse effect can be attributed to the non-CO2 greenhouse gases. EPA collects data on international historical and projected greenhouse gas emissions and estimates the costs of reducing these emissions, and has issued several analytical reports on international emissions projections and mitigation opportunities for the non-CO2 greenhouse gases. International Analyses
In the U.S., anthropogenic methane is approx 10% whereas CO2 from fossil-fuels is 80% of our GHG emissions.
Energy-related carbon dioxide emissions, resulting from petroleum and natural gas, represent 82 percent of total U.S. human-made greenhouse gas emissions. U.S. Anthropogenic Greenhouse Gas Emissions by Gas, 2001 (Million Metric Tons of Carbon Equivalent)