Demands for nutritious meal as population multiply Cows are overbreed, in order to meet the demand of beef and milk for human beings. Each cow produces 100 kg of methane per year, which is equal to 2300 kg of CO2 per year. In addition, humans are clearing rain forests into farmland or grazing land, so the population of livestock can increase. This is responsible for 2.8 billions metric tons of CO2 emission per year.
If human reduces the consumption of red meat, cows population will decline, and this can reduce the 20% significance of the main causes for global warming.