• Question: How much gas do cows stink into the atmosphere a day?

    Asked by conn207 to Antonia, Douglas, Hugh, Matt, Tom on 24 Jun 2010 in Categories: .
    • Photo: Matthew Hurley

      Matthew Hurley answered on 13 Jun 2010:

      I don’t know – does it depend on how much air they swallow?

    • Photo: Douglas Blane

      Douglas Blane answered on 24 Jun 2010:

      A lot. Scientists have different estimates. Some say 100 to 200 litres a day. Others say 500 litres. (So that’s about 26 to 53 gallons, or as much as 132 gallons.)

      Multiply that by the number of cows in the world – around 1.5 billion – and you get anything up to 200 billion gallons of methane. A day.

      Cows produce 3% of Britain’s greenhouse gas emissions. But 25 to 30% of its methane. And methane is much worse than carbon dioxide as a greenhouse gas – about 23 times as bad.

      Most of the methane comes out of a cow’s mouth by belching. But a fair bit comes from the other end as well.

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