The Danish Tax Commission estimates that a cow will emit four tonnes of methane a year in burps and flatulence compared with 2.7 tonnes of carbon dioxide for an average car.

• 丹麦税务委员会估算，一头奶牛因为打嗝和胃部胀气，每年释放4吨的甲烷，而每辆车每年平均排放的二氧化碳才只有2.；7吨。