EVERYDAY SCIENCE

Detailed explanation-1: -The concentration of methane in the atmosphere has more than doubled since preindustrial times, reaching over 1, 800 ppb in recent years (see the range of measurements for 2020 and 2021 in Figure 2). This increase is predominantly due to agriculture and fossil fuel use.

Detailed explanation-2: -The largest sources of methane emissions from human activities in the United States are oil and gas systems, livestock enteric fermentation, and landfills.

Detailed explanation-3: -In fact, 14.5 percent of all human-caused greenhouse gas (GHG) emissions come from livestock supply chains. They amount to 7.1 gigatonnes (GT) of carbon dioxide equivalent (CO2-eq) per year. The main sources of emissions are feed production and processing, and methane from ruminants’ digestion.

Detailed explanation-4: -with an uncertainty of about 15%. Of this, cattle contribute about 74%. Buffalos and sheep each account for 8-9%, and the remainder stems from camels, mules and asses, pigs, and horses. Human CH, production is probably less than I Tg per year.